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source: palm/trunk/SOURCE/multi_agent_system_mod.f90 @ 3159

Last change on this file since 3159 was 3159, checked in by sward, 6 years ago
Added multi agent system
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1	!> @file multi_agent_system_mod.f90
2	!--------------------------------------------------------------------------------!
3	! This file is part of PALM-4U.
4	!
5	! PALM-4U is free software: you can redistribute it and/or modify it under the
6	! terms of the GNU General Public License as published by the Free Software
7	! Foundation, either version 3 of the License, or (at your option) any later
8	! version.
9	!
10	! PALM-4U is distributed in the hope that it will be useful, but WITHOUT ANY
11	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13	!
14	! You should have received a copy of the GNU General Public License along with
15	! PALM. If not, see <http://www.gnu.org/licenses/>.
16	!
17	! Copyright 2016 Leibniz Universitaet Hannover
18	!------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! ------------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: multi_agent_system_mod.f90 3159 2018-07-20 11:20:01Z sward $
27	! Initial revision
28	!
29	!
30	!
31	! Authors:
32	! --------
33	! @author sward
34	!
35	!
36	! Description:
37	! ------------
38	!> Multi Agent System for the simulation of pedestrian movement in urban
39	!> environments
40	!------------------------------------------------------------------------------!
41	MODULE multi_agent_system_mod
42
43	USE, INTRINSIC :: ISO_C_BINDING
44
45	USE constants, &
46	ONLY: pi
47
48	USE control_parameters, &
49	ONLY: dt_3d, message_string, simulated_time, dt_write_agent_data
50
51	USE cpulog, &
52	ONLY: cpu_log, log_point, log_point_s
53
54	USE grid_variables, &
55	ONLY: ddx, ddy, dx, dy
56
57	USE indices, &
58	ONLY: nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
59	wall_flags_0
60
61	USE random_function_mod, &
62	ONLY: random_function
63
64	USE kinds
65
66	USE pegrid
67
68	CHARACTER(LEN=15) :: bc_mas_lr = 'absorb' !< left/right boundary condition
69	CHARACTER(LEN=15) :: bc_mas_ns = 'absorb' !< north/south boundary condition
70
71	INTEGER(iwp) :: deleted_agents = 0 !< number of deleted agents per time step
72	INTEGER(iwp) :: heap_count !< number of items in binary heap (for pathfinding)
73	INTEGER(iwp) :: ibc_mas_lr !< agent left/right boundary condition dummy
74	INTEGER(iwp) :: ibc_mas_ns !< agent north/south boundary condition dummy
75	INTEGER(iwp) :: ind_pm10 = -9 !< chemical species index of PM10
76	INTEGER(iwp) :: ind_pm25 = -9 !< chemical species index of PM2.5
77	INTEGER(iwp) :: iran_agent = -1234567 !< number for random generator
78	INTEGER(iwp) :: min_nr_agent = 2 !< namelist parameter (see documentation)
79	INTEGER(iwp) :: ghla_count_recv !< number of agents in left ghost layer
80	INTEGER(iwp) :: ghna_count_recv !< number of agents in north ghost layer
81	INTEGER(iwp) :: ghra_count_recv !< number of agents in right ghost layer
82	INTEGER(iwp) :: ghsa_count_recv !< number of agents in south ghost layer
83	INTEGER(iwp) :: nr_move_north !< number of agts to move north during exchange_horiz
84	INTEGER(iwp) :: nr_move_south !< number of agts to move south during exchange_horiz
85	INTEGER(iwp) :: number_of_agents = 0 !< number of agents for each grid box (3d array is saved on agt_count)
86	INTEGER(iwp) :: number_of_agent_groups = 1 !< namelist parameter (see documentation)
87	INTEGER(iwp) :: sort_count_mas = 0 !< counter for sorting agents
88	INTEGER(iwp) :: step_dealloc_mas = 100 !< namelist parameter (see documentation)
89	INTEGER(iwp) :: total_number_of_agents !< total number of agents in the whole model domain
90
91	INTEGER(iwp), PARAMETER :: NR_2_direction_move = 10000 !< parameter for agent exchange
92	INTEGER(iwp), PARAMETER :: PHASE_INIT = 1 !< phase parameter
93	INTEGER(iwp), PARAMETER :: PHASE_RELEASE = 2 !< phase parameter
94
95	INTEGER(iwp), PARAMETER :: max_number_of_agent_groups = 100 !< maximum allowed number of agent groups
96
97	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: agt_count !< 3d array of number of agents of every grid box
98	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: s_measure_height !< k-index(s-grid) for measurement
99	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: top_top_s !< k-index of first s-gridpoint above topography
100	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: top_top_w !< k-index of first v-gridpoint above topography
101	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: obstacle_flags !< flags to identify corners and edges of topography that cannot be crossed by agents
102
103	LOGICAL :: deallocate_memory_mas = .TRUE. !< namelist parameter (see documentation)
104	LOGICAL :: dt_3d_reached_mas !< flag: agent timestep has reached model timestep
105	LOGICAL :: dt_3d_reached_l_mas !< flag: agent timestep has reached model timestep
106	LOGICAL :: agents_active = .FALSE. !< flag for agent system
107	LOGICAL :: random_start_position_agents = .TRUE. !< namelist parameter (see documentation)
108	LOGICAL :: read_agents_from_restartfile = .TRUE. !< namelist parameter (see documentation)
109	LOGICAL :: agent_own_timestep = .FALSE. !< namelist parameter (see documentation)
110
111	LOGICAL, DIMENSION(max_number_of_agent_groups) :: a_rand_target = .FALSE. !< namelist parameter (see documentation)
112
113	REAL(wp) :: agent_maximum_age = 9999999.9_wp !< namelist parameter (see documentation)
114	REAL(wp) :: alloc_factor_mas = 20.0_wp !< namelist parameter (see documentation)
115	REAL(wp) :: coll_t_0 = 3. !< namelist parameter (see documentation)
116	REAL(wp) :: corner_gate_start = 0.7_wp !< namelist parameter (see documentation)
117	REAL(wp) :: corner_gate_width = 1.0_wp !< namelist parameter (see documentation)
118	REAL(wp) :: d_sigma_rep_agent !< inverse of sigma_rep_agent
119	REAL(wp) :: d_sigma_rep_wall !< inverse of sigma_rep_wall
120	REAL(wp) :: d_tau_accel_agent !< inverse of tau_accel_agent
121	REAL(wp) :: desired_speed = 1.2_wp !< namelist parameter (see documentation)
122	REAL(wp) :: des_sp_sig = .2_wp !< namelist parameter (see documentation)
123	REAL(wp) :: dist_target_reached = 2.0_wp !< distance at which target counts as reached
124	REAL(wp) :: dist_to_int_target = .75_wp !< namelist parameter (see documentation)
125	REAL(wp) :: d_sqrt_2 = 1.0_wp/SQRT(2.) !< 1/sqrt(2)
126	REAL(wp) :: dt_agent = 0.016_wp !< namelist parameter (see documentation)
127	REAL(wp) :: dt_arel = 9999999.9_wp !< namelist parameter (see documentation)
128	REAL(wp) :: end_time_arel = 9999999.9_wp !< namelist parameter (see documentation)
129	REAL(wp) :: force_x !< dummy value for force on current agent in x-direction
130	REAL(wp) :: force_y !< dummy value for force on current agent in y-direction
131	REAL(wp) :: max_dist_from_path = 1.0_wp !< distance from current path at which a new path is calculated
132	REAL(wp) :: multi_agent_system_start = 0.0_wp !< namelist parameter (see documentation)
133	REAL(wp) :: radius_agent = .2_wp !< namelist parameter (see documentation)
134	REAL(wp) :: repuls_agent = 1.5_wp !< namelist parameter (see documentation)
135	REAL(wp) :: repuls_wall = 7.0_wp !< namelist parameter (see documentation)
136	REAL(wp) :: scan_radius_agent = 3.0_wp !< namelist parameter (see documentation)
137	REAL(wp) :: scan_radius_wall = 2.0_wp !< namelist parameter (see documentation)
138	REAL(wp) :: sigma_rep_agent = 0.3_wp !< namelist parameter (see documentation)
139	REAL(wp) :: sigma_rep_wall = 0.2_wp !< namelist parameter (see documentation)
140	REAL(wp) :: tau_accel_agent = 0.5_wp !< namelist parameter (see documentation)
141	REAL(wp) :: time_arel = 0.0_wp !< time for agent release
142	REAL(wp) :: time_write_agent_data = 0.0_wp !< write agent data at current time on file
143	REAL(wp) :: v_max_agent = 1.3_wp !< namelist parameter (see documentation)
144
145
146	REAL(wp), DIMENSION(max_number_of_agent_groups) :: adx = 9999999.9_wp !< namelist parameter (see documentation)
147	REAL(wp), DIMENSION(max_number_of_agent_groups) :: ady = 9999999.9_wp !< namelist parameter (see documentation)
148	REAL(wp), DIMENSION(max_number_of_agent_groups) :: asl = 9999999.9_wp !< namelist parameter (see documentation)
149	REAL(wp), DIMENSION(max_number_of_agent_groups) :: asn = 9999999.9_wp !< namelist parameter (see documentation)
150	REAL(wp), DIMENSION(max_number_of_agent_groups) :: asr = 9999999.9_wp !< namelist parameter (see documentation)
151	REAL(wp), DIMENSION(max_number_of_agent_groups) :: ass = 9999999.9_wp !< namelist parameter (see documentation)
152	REAL(wp), DIMENSION(max_number_of_agent_groups) :: at_x = 9999999.9_wp !< namelist parameter (see documentation)
153	REAL(wp), DIMENSION(max_number_of_agent_groups) :: at_y = 9999999.9_wp !< namelist parameter (see documentation)
154	!
155	!-- Type for the definition of an agent
156	TYPE agent_type
157	INTEGER(iwp) :: block_nr !< number for sorting
158	INTEGER(iwp) :: group !< number of agent group
159	INTEGER(idp) :: id !< particle ID (64 bit integer)
160	INTEGER(iwp) :: path_counter !< current target along path (path_x/y)
161	LOGICAL :: agent_mask !< if this parameter is set to false the agent will be deleted
162	REAL(wp) :: age !< age of agent
163	REAL(wp) :: age_m !< age of agent
164	REAL(wp) :: dt_sum !< sum of agents subtimesteps
165	REAL(wp) :: clo !< clothing index
166	REAL(wp) :: energy_storage !< energy stored by agent
167	REAL(wp) :: force_x !< force term x-direction
168	REAL(wp) :: force_y !< force term y-direction
169	REAL(wp) :: origin_x !< origin x-position of agent
170	REAL(wp) :: origin_y !< origin y-position of agent
171	REAL(wp) :: pm10 !< PM10 concentration at agent position
172	REAL(wp) :: pm25 !< PM25 concentration at agent position
173	REAL(wp) :: speed_abs !< absolute value of agent speed
174	REAL(wp) :: speed_e_x !< normalized speed of agent in x
175	REAL(wp) :: speed_e_y !< normalized speed of agent in y
176	REAL(wp) :: speed_des !< agent's desired speed
177	REAL(wp) :: speed_x !< speed of agent in x
178	REAL(wp) :: speed_y !< speed of agent in y
179	REAL(wp) :: thermal_index !< the dynamic thermal index
180	REAL(wp) :: windspeed !< absolute value of windspeed at agent position
181	REAL(wp) :: x !< x-position
182	REAL(wp) :: y !< y-position
183	REAL(wp) :: t !< temperature
184	REAL(wp) :: t_x !< x-position
185	REAL(wp) :: t_y !< y-position
186	REAL(wp), DIMENSION(0:15) :: path_x !< agent path to target (x)
187	REAL(wp), DIMENSION(0:15) :: path_y !< agent path to target (y)
188	END TYPE agent_type
189
190	TYPE(agent_type), DIMENSION(:), POINTER :: agents !< Agent array for this grid cell
191	TYPE(agent_type) :: zero_agent !< zero agent to avoid weird thing
192	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: move_also_north !< for agent exchange between PEs
193	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: move_also_south !< for agent exchange between PEs
194	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: agt_gh_l !< ghost layer left of pe domain
195	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: agt_gh_n !< ghost layer north of pe domain
196	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: agt_gh_r !< ghost layer right of pe domain
197	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: agt_gh_s !< ghost layer south of pe domain
198	!
199	!-- Type for 2D grid on which agents are stored
200	TYPE grid_agent_def
201	INTEGER(iwp), DIMENSION(0:3) :: start_index !< start agent index for current block
202	INTEGER(iwp), DIMENSION(0:3) :: end_index !< end agent index for current block
203	INTEGER(iwp) :: id_counter !< agent id counter (removeable?)
204	LOGICAL :: time_loop_done !< timestep loop for agent advection
205	TYPE(agent_type), POINTER, DIMENSION(:) :: agents !< Particle array for this grid cell
206	END TYPE grid_agent_def
207
208	TYPE(grid_agent_def), DIMENSION(:,:), ALLOCATABLE, TARGET :: grid_agents !< 2D grid on which agents are stored
209	!
210	!-- Item in a priority queue (binary heap)
211	TYPE heap_item
212	INTEGER(iwp) :: mesh_id !< id of the submitted mesh point
213	REAL(wp) :: priority !< priority of the mesh point (= distance so far + heuristic to goal)
214	END TYPE heap_item
215
216	TYPE(heap_item), DIMENSION(:), ALLOCATABLE :: queue !< priority queue realized as binary heap
217	!
218	!-- Type for mesh point in visibility graph
219	TYPE mesh_point
220	INTEGER(iwp) :: polygon_id !< Polygon the point belongs to
221	INTEGER(iwp) :: vertex_id !< Vertex in the polygon
222	INTEGER(iwp) :: noc !< number of connections
223	INTEGER(iwp) :: origin_id !< ID of previous mesh point on path (A*)
224	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: connected_vertices !< Index of connected vertices
225	REAL(wp) :: cost_so_far !< Cost to reach this mesh point (A*)
226	REAL(wp) :: x !< x-coordinate
227	REAL(wp) :: y !< y-coordinate
228	REAL(wp) :: x_s !< corner shifted outward from building by 1m (x)
229	REAL(wp) :: y_s !< corner shifted outward from building by 1m (y)
230	REAL(wp), DIMENSION(:), ALLOCATABLE :: distance_to_vertex !< Distance to each vertex
231	END TYPE mesh_point
232
233	TYPE(mesh_point), DIMENSION(:), ALLOCATABLE :: mesh !< navigation mesh
234	TYPE(mesh_point), DIMENSION(:), ALLOCATABLE :: tmp_mesh !< temporary navigation mesh
235	!
236	!-- Vertex of a polygon
237	TYPE vertex_type
238	LOGICAL :: delete !< Flag to mark vertex for deletion
239	REAL(wp) :: x !< x-coordinate
240	REAL(wp) :: y !< y-coordinate
241	END TYPE vertex_type
242	!
243	!-- Polygon containing a number of vertices
244	TYPE polygon_type
245	INTEGER(iwp) :: nov !< Number of vertices in this polygon
246	TYPE(vertex_type), DIMENSION(:), ALLOCATABLE :: vertices !< Array of vertices
247	END TYPE polygon_type
248
249	TYPE(polygon_type), DIMENSION(:), ALLOCATABLE :: polygons !< Building data in polygon form
250
251	SAVE
252
253	PRIVATE
254	!
255	!-- Public functions
256	PUBLIC mas_init, mas_parin, multi_agent_system
257
258	!
259	!-- Public parameters, constants and initial values
260	PUBLIC agents_active, multi_agent_system_start
261
262	INTERFACE mas_parin
263	MODULE PROCEDURE mas_parin
264	END INTERFACE mas_parin
265
266	INTERFACE mas_init
267	MODULE PROCEDURE mas_init
268	END INTERFACE mas_init
269
270	INTERFACE multi_agent_system
271	MODULE PROCEDURE multi_agent_system
272	END INTERFACE multi_agent_system
273
274	CONTAINS
275
276
277	!------------------------------------------------------------------------------!
278	! Description:
279	! ------------
280	!> Multi Agent System:
281	!> executes a number of agents sub-timesteps until the model timestep is reached.
282	!> The agent timestep is usually smaller than the model timestep
283	!------------------------------------------------------------------------------!
284	SUBROUTINE multi_agent_system
285
286	! USE htcm_mod, &
287	! ONLY: htcm_dynamic
288
289	IMPLICIT NONE
290
291	INTEGER(iwp) :: i !< counter
292	INTEGER(iwp) :: ie !< counter
293	INTEGER(iwp) :: is !< counter
294	INTEGER(iwp) :: j !< counter
295	INTEGER(iwp) :: je !< counter
296	INTEGER(iwp) :: js !< counter
297	INTEGER(iwp), SAVE :: mas_count = 0 !< counts the mas-calls
298
299	LOGICAL :: first_loop_stride !< flag for first loop stride of agent sub-timesteps
300	LOGICAL :: first_call = .TRUE. !< first call of mas flag for output
301
302	CALL cpu_log( log_point(9), 'mas', 'start' )
303	!
304	!-- Initialize variables for the next (sub-) timestep, i.e., for marking
305	!-- those agents to be deleted after the timestep
306	deleted_agents = 0
307	!
308	!-- If necessary, release new set of agents
309	IF ( time_arel >= dt_arel .AND. end_time_arel > simulated_time ) THEN
310
311	CALL mas_create_agent(PHASE_RELEASE)
312	!
313	!-- The MOD function allows for changes in the output interval with
314	!-- restart runs.
315	time_arel = MOD( time_arel, MAX( dt_arel, dt_3d ) )
316
317	ENDIF
318
319	first_loop_stride = .TRUE.
320	grid_agents(:,:)%time_loop_done = .TRUE.
321	!
322	!-- Set timestep variable
323	IF ( .NOT. agent_own_timestep ) dt_agent = dt_3d
324	!
325	!-- Timestep loop for agent transport.
326	!-- This loop has to be repeated until the transport time of every agent
327	!-- (within the total domain!) has reached the LES timestep (dt_3d).
328	!-- Timestep scheme is Euler-forward
329	DO
330	!
331	!-- Write agent data at current time on file.
332	time_write_agent_data = time_write_agent_data + dt_agent
333	IF ( time_write_agent_data >= dt_write_agent_data ) THEN
334	#if defined( __netcdf )
335	IF ( first_loop_stride ) CALL mas_get_prognostic_quantities
336	CALL mas_data_output_agents ( first_call )
337	#else
338	WRITE( message_string, * ) 'NetCDF is needed for agent output. ', &
339	'Set __netcdf in compiler options'
340	CALL message( 'multi_agent_system', 'PA0071', 1, 2, 0, 6, 0 )
341	#endif
342	IF(first_call) first_call = .FALSE.
343	time_write_agent_data = time_write_agent_data - dt_write_agent_data
344	ENDIF
345	!
346	!-- Start logging
347	CALL cpu_log( log_point_s(9), 'mas_transport', 'start' )
348	CALL cpu_log( log_point_s(9), 'mas_transport', 'pause' )
349	CALL cpu_log( log_point_s(16), 'mas_other_agents', 'start' )
350	CALL cpu_log( log_point_s(16), 'mas_other_agents', 'pause' )
351	!
352	!-- Flag is true by default, will be set to false if an agent has not yet
353	!-- reached the model timestep
354	grid_agents(:,:)%time_loop_done = .TRUE.
355
356	!
357	!-- First part of agent transport:
358	!-- Evaluate social forces for all agents at current positions
359	DO i = nxl, nxr
360	DO j = nys, nyn
361
362	number_of_agents = agt_count(j,i)
363	!
364	!-- If grid cell is empty, cycle
365	IF ( number_of_agents <= 0 ) CYCLE
366
367	agents => grid_agents(j,i)%agents(1:number_of_agents)
368	!
369	!-- Evaluation of social forces
370	CALL mas_timestep_forces_call(i,j)
371
372	ENDDO
373	ENDDO
374	!
375	!-- Second part of agent transport:
376	!-- timestep
377	DO i = nxl, nxr
378	DO j = nys, nyn
379
380	number_of_agents = agt_count(j,i)
381	!
382	!-- If grid cell is empty, flag must be true
383	IF ( number_of_agents <= 0 ) THEN
384	grid_agents(j,i)%time_loop_done = .TRUE.
385	CYCLE
386	ENDIF
387
388	agents => grid_agents(j,i)%agents(1:number_of_agents)
389
390	agents(1:number_of_agents)%agent_mask = .TRUE.
391	!
392	!-- Initialize the variable storing the total time that an agent
393	!-- has advanced within the timestep procedure
394	IF ( first_loop_stride ) THEN
395	agents(1:number_of_agents)%dt_sum = 0.0_wp
396	ENDIF
397	!
398	!-- Initialize the switch used for the loop exit condition checked
399	!-- at the end of this loop. If at least one agent has failed to
400	!-- reach the LES timestep, this switch will be set false in
401	!-- mas_transport.
402	dt_3d_reached_l_mas = .TRUE.
403	!
404	!-- Timestep
405	CALL mas_timestep
406	!
407	!-- Delete agents that have been simulated longer than allowed
408	CALL mas_boundary_conds( 'max_sim_time' )
409	!
410	!-- Delete agents that have reached target area
411	CALL mas_boundary_conds( 'target_area' )
412	!
413	!--- If not all agents of the actual grid cell have reached the
414	!-- LES timestep, this cell has to to another loop iteration. Due to
415	!-- the fact that agents can move into neighboring grid cell,
416	!-- these neighbor cells also have to perform another loop iteration
417	IF ( .NOT. dt_3d_reached_l_mas ) THEN
418	js = MAX(nys,j-1)
419	je = MIN(nyn,j+1)
420	is = MAX(nxl,i-1)
421	ie = MIN(nxr,i+1)
422	grid_agents(js:je,is:ie)%time_loop_done = .FALSE.
423	ENDIF
424
425	ENDDO
426	ENDDO
427
428	!
429	!-- Find out, if all agents on every PE have completed the LES timestep
430	!-- and set the switch corespondingly
431	dt_3d_reached_l_mas = ALL(grid_agents(:,:)%time_loop_done)
432	#if defined( __parallel )
433	IF ( collective_wait ) CALL MPI_BARRIER( comm2d, ierr )
434	CALL MPI_ALLREDUCE( dt_3d_reached_l_mas, dt_3d_reached_mas, 1, MPI_LOGICAL, &
435	MPI_LAND, comm2d, ierr )
436	#else
437	dt_3d_reached_mas = dt_3d_reached_l_mas
438	#endif
439
440	CALL cpu_log( log_point_s(9), 'mas_transport', 'stop' )
441	CALL cpu_log( log_point_s(16), 'mas_other_agents', 'stop' )
442	!
443	!-- Increment time since last release
444	IF ( dt_3d_reached_mas ) time_arel = time_arel + dt_3d
445
446	!
447	!-- Move Agents local to PE to a different grid cell
448	CALL mas_eh_move_agent
449	!
450	!-- Horizontal boundary conditions including exchange between subdmains
451	CALL mas_eh_exchange_horiz
452	!
453	!-- Pack agents (eliminate those marked for deletion),
454	!-- determine new number of agents
455	CALL mas_ps_sort_in_subboxes
456	!
457	!-- Initialize variables for the next (sub-) timestep, i.e., for marking
458	!-- those agents to be deleted after the timestep
459	deleted_agents = 0
460	!
461	!-- to be included here: call of human thermal comfort mod (and UV exposure)
462	! DO i = nxl, nxr
463	! DO j = nys, nyn
464	!
465	! number_of_agents = agt_count(j,i)
466	! !
467	! !-- If grid cell gets empty, cycle
468	! IF ( number_of_agents <= 0 ) CYCLE
469	!
470	! agents => grid_agents(j,i)%agents(1:number_of_agents)
471	! !
472	! !-- Evaluation of social forces
473	! CALL htcm_dynamic(i,j)
474	!
475	! ENDDO
476	! ENDDO
477
478	IF ( dt_3d_reached_mas ) EXIT
479
480	first_loop_stride = .FALSE.
481	ENDDO ! timestep loop
482
483	!
484	!-- Deallocate unused memory
485	IF ( deallocate_memory_mas .AND. mas_count == step_dealloc_mas ) THEN
486	CALL mas_eh_dealloc_agents_array
487	mas_count = 0
488	ELSEIF ( deallocate_memory_mas ) THEN
489	mas_count = mas_count + 1
490	ENDIF
491
492	CALL cpu_log( log_point(9), 'mas', 'stop' )
493
494	END SUBROUTINE multi_agent_system
495
496	!------------------------------------------------------------------------------!
497	! Description:
498	! ------------
499	!> Calculation of the direction vector from each agent to its current
500	!> intermittent target
501	!------------------------------------------------------------------------------!
502	SUBROUTINE mas_agent_direction
503
504	IMPLICIT NONE
505
506	LOGICAL :: path_flag !< true if new path must be calculated
507
508	INTEGER(iwp) :: n !< loop variable over all agents in a grid box
509	INTEGER(iwp) :: pc !< agent path counter
510
511	REAL(wp) :: abs_dir !< length of direction vector (for normalization)
512	REAL(wp) :: d_curr_target !< rounding influence expressed as x speed component
513	REAL(wp) :: d_prev_target !< rounding influence expressed as x speed component
514	REAL(wp) :: dir_x !< direction of agent (x)
515	REAL(wp) :: dir_y !< direction of agent (y)
516	REAL(wp) :: dist_round = 3. !< distance at which agents start rounding a corner
517	REAL(wp) :: dtit !< distance to intermittent target
518	REAL(wp) :: round_fac = .2 !< factor for rounding influence
519	REAL(wp) :: speed_round_x !< rounding influence expressed as x speed component
520	REAL(wp) :: speed_round_y !< rounding influence expressed as x speed component
521
522	CALL cpu_log( log_point_s(9), 'mas_transport', 'continue' )
523	!
524	!-- loop over all agents in the current grid box
525	DO n = 1, number_of_agents
526	path_flag = .FALSE.
527	pc = agents(n)%path_counter
528	!
529	!-- If no path was calculated for agent yet, do it
530	IF ( pc >= 999 ) THEN
531
532	agents(n)%path_x(0) = agents(n)%origin_x
533	agents(n)%path_y(0) = agents(n)%origin_y
534	CALL mas_nav_find_path(n)
535	pc = agents(n)%path_counter
536	!
537	!-- Check if new path must be calculated and if so, do it
538	ELSE
539	!
540	!-- Case one: Agent has come close enough to intermittent target.
541	!-- -> chose new int target and calculate rest of path if no
542	!-- new intermittent targets are left
543	dtit = SQRT((agents(n)%x - agents(n)%path_x(pc))**2 &
544	+ (agents(n)%y - agents(n)%path_y(pc))**2)
545	IF ( dtit < dist_to_int_target ) THEN
546	agents(n)%path_counter = agents(n)%path_counter + 1
547	pc = agents(n)%path_counter
548	!
549	!-- Path counter out of scope (each agent can store a maximum of 15
550	!-- intermittent targets on the way to her final target); new path
551	!-- must be calculated
552	IF ( pc >= SIZE(agents(n)%path_x) ) THEN
553	path_flag = .TRUE.
554	ENDIF
555	!
556	!-- Case two: Agent too far from path
557	!-- -> set flag for new path to be calculated
558	ELSEIF ( dist_point_to_edge(agents(n)%path_x(pc-1), &
559	agents(n)%path_y(pc-1), &
560	agents(n)%path_x(pc), &
561	agents(n)%path_y(pc), &
562	agents(n)%x, agents(n)%y) &
563	> max_dist_from_path ) &
564	THEN
565	path_flag = .TRUE.
566	ENDIF
567	!
568	!-- If either of the above two cases was true, calculate new path and
569	!-- reset 0th path point. This point (the last target the agent had)
570	!-- is needed for the agents rounding of corners and the calculation
571	!-- of her deviation from her current path
572	IF ( path_flag ) THEN
573	agents(n)%path_x(0) = agents(n)%path_x(pc-1)
574	agents(n)%path_y(0) = agents(n)%path_y(pc-1)
575	CALL mas_nav_find_path(n)
576	pc = agents(n)%path_counter
577	ENDIF
578	ENDIF
579	!
580	!-- Normalize direction vector
581	abs_dir = 1.0d-12
582	dir_x = agents(n)%path_x(pc) - agents(n)%x
583	dir_y = agents(n)%path_y(pc) - agents(n)%y
584	abs_dir = SQRT(dir_x2 + dir_y2)+1.0d-12
585	!-- needed later for corner rounding
586	! dir_x = dir_x/abs_dir
587	! dir_y = dir_y/abs_dir
588	! dir_x = dir_x + speed_round_x
589	! dir_y = dir_y + speed_round_y
590	! abs_dir = SQRT(dir_x2 + dir_y2)+1.0d-12
591	agents(n)%speed_e_x = dir_x/abs_dir
592	agents(n)%speed_e_y = dir_y/abs_dir
593	ENDDO
594
595	CALL cpu_log( log_point_s(9), 'mas_transport', 'pause' )
596	!
597	!-- corner rounding; to be added
598	!
599	!-- Calculate direction change due to rounding of corners
600
601	! speed_round_x = 0.
602	! speed_round_y = 0.
603	!
604	! d_curr_target = SQRT( (agents(n)%path_x(pc) - agents(n)%x)**2 + &
605	! (agents(n)%path_y(pc) - agents(n)%y)**2 )
606	! d_prev_target = SQRT( (agents(n)%path_x(pc-1) - agents(n)%x)**2 + &
607	! (agents(n)%path_y(pc-1) - agents(n)%y)**2 )
608	! !
609	! !-- Agent is close to next target and that target is not the final one
610	! IF ( d_curr_target < dist_round .AND. dist_round < &
611	! SQRT( (agents(n)%path_x(pc) - agents(n)%t_x)**2 + &
612	! (agents(n)%path_y(pc) - agents(n)%t_y)**2 ) ) &
613	! THEN
614	! speed_round_x = (agents(n)%path_x(pc+1) - agents(n)%path_x(pc)) / &
615	! ABS( agents(n)%path_x(pc) &
616	! - agents(n)%path_x(pc+1)) * round_fac * &
617	! SIN( pi/dist_round*d_curr_target )
618	! speed_round_y = (agents(n)%path_y(pc+1) - agents(n)%path_y(pc)) / &
619	! ABS( agents(n)%path_y(pc) &
620	! - agents(n)%path_y(pc+1)) * round_fac * &
621	! SIN( pi/dist_round*d_curr_target )
622	! ENDIF
623	!
624	! IF ( d_prev_target < dist_round ) THEN
625	! IF ( agents(n)%path_x(pc) /= agents(n)%path_x(pc+1) ) THEN
626	! speed_round_x = speed_round_x + &
627	! (agents(n)%path_x(pc) - agents(n)%path_x(pc+1)) / &
628	! ABS( agents(n)%path_x(pc) &
629	! - agents(n)%path_x(pc+1)) * round_fac * &
630	! SIN( pi/dist_round*d_prev_target )
631	! ENDIF
632	!
633	! IF ( agents(n)%path_y(pc) /= agents(n)%path_y(pc+1) ) THEN
634	! speed_round_y = speed_round_y + &
635	! (agents(n)%path_y(pc) - agents(n)%path_y(pc+1)) / &
636	! ABS( agents(n)%path_y(pc) &
637	! - agents(n)%path_y(pc+1)) * round_fac * &
638	! SIN( pi/dist_round*d_prev_target )
639	! ENDIF
640
641	! ENDIF
642
643
644	END SUBROUTINE mas_agent_direction
645
646	!------------------------------------------------------------------------------!
647	! Description:
648	! ------------
649	!> Boundary conditions for maximum time, target reached and out of domain
650	!------------------------------------------------------------------------------!
651	SUBROUTINE mas_boundary_conds( location )
652
653	IMPLICIT NONE
654
655	CHARACTER (LEN=*) :: location !< Identifier
656
657	INTEGER(iwp) :: n !< agent number
658	INTEGER(iwp) :: grp !< agent group
659
660	REAL(wp) :: dist_to_target !< distance to target
661
662	IF ( location == 'max_sim_time' ) THEN
663
664	!
665	!-- Delete agents that have been simulated longer than allowed
666	DO n = 1, number_of_agents
667
668	IF ( agents(n)%age > agent_maximum_age .AND. &
669	agents(n)%agent_mask ) &
670	THEN
671	agents(n)%agent_mask = .FALSE.
672	deleted_agents = deleted_agents + 1
673	ENDIF
674
675	ENDDO
676	ENDIF
677
678	IF ( location == 'target_area' ) THEN
679
680	!
681	!-- Delete agents that entered target region
682	DO n = 1, number_of_agents
683	grp = agents(n)%group
684	dist_to_target = SQRT((agents(n)%x-at_x(grp))**2 &
685	+ (agents(n)%y-at_y(grp))**2)
686	IF ( dist_to_target < dist_target_reached ) THEN
687	agents(n)%agent_mask = .FALSE.
688	deleted_agents = deleted_agents + 1
689	ENDIF
690
691	ENDDO
692	ENDIF
693
694	END SUBROUTINE mas_boundary_conds
695
696	!------------------------------------------------------------------------------!
697	! Description:
698	! ------------
699	!> Release new agents at their respective sources
700	!------------------------------------------------------------------------------!
701	SUBROUTINE mas_create_agent (phase)
702
703	IMPLICIT NONE
704
705	INTEGER(iwp) :: alloc_size !< relative increase of allocated memory for agents
706	INTEGER(iwp) :: i !< loop variable ( agent groups )
707	INTEGER(iwp) :: ip !< index variable along x
708	INTEGER(iwp) :: j !< loop variable ( agents per point )
709	INTEGER(iwp) :: jp !< index variable along y
710	INTEGER(iwp) :: loop_stride !< loop variable for initialization
711	INTEGER(iwp) :: n !< loop variable ( number of agents )
712	INTEGER(iwp) :: new_size !< new size of allocated memory for agents
713	INTEGER(iwp) :: rn_side !< index of agent path
714
715	INTEGER(iwp), INTENT(IN) :: phase !< mode of inititialization
716
717	INTEGER(iwp), DIMENSION(nysg:nyng,nxlg:nxrg) :: local_count !< start address of new agent
718	INTEGER(iwp), DIMENSION(nysg:nyng,nxlg:nxrg) :: local_start !< start address of new agent
719
720	LOGICAL :: first_stride !< flag for initialization
721
722	REAL(wp) :: pos_x !< increment for agent position in x
723	REAL(wp) :: pos_y !< increment for agent position in y
724	REAL(wp) :: rand_contr !< dummy argument for random position
725	REAL(wp) :: rn_side_dum !< index of agent path
726
727	TYPE(agent_type),TARGET :: tmp_agent !< temporary agent used for initialization
728
729	!
730	!-- Calculate agent positions and store agent attributes, if
731	!-- agent is situated on this PE
732	DO loop_stride = 1, 2
733	first_stride = (loop_stride == 1)
734	IF ( first_stride ) THEN
735	local_count = 0 ! count number of agents
736	ELSE
737	local_count = agt_count ! Start address of new agents
738	ENDIF
739
740	DO i = 1, number_of_agent_groups
741
742	pos_y = ass(i)
743
744	DO WHILE ( pos_y <= asn(i) )
745
746	IF ( pos_y >= nys * dy .AND. &
747	pos_y < ( nyn + 1 ) * dy ) &
748	THEN
749
750	pos_x = asl(i)
751
752	xloop: DO WHILE ( pos_x <= asr(i) )
753
754	IF ( pos_x >= nxl * dx .AND. &
755	pos_x < ( nxr + 1) * dx ) &
756	THEN
757
758	tmp_agent%agent_mask = .TRUE.
759	tmp_agent%group = i
760	tmp_agent%id = 0_idp
761	tmp_agent%block_nr = -1
762	tmp_agent%path_counter = 999 !SIZE(tmp_agent%path_x)
763	tmp_agent%age = 0.0_wp
764	tmp_agent%age_m = 0.0_wp
765	tmp_agent%dt_sum = 0.0_wp
766	tmp_agent%clo = 99999.0_wp
767	tmp_agent%energy_storage= 0.0_wp
768	tmp_agent%force_x = 0.0_wp
769	tmp_agent%force_y = 0.0_wp
770	tmp_agent%origin_x = pos_x
771	tmp_agent%origin_y = pos_y
772	tmp_agent%speed_abs = 0.0_wp
773	tmp_agent%speed_e_x = 0.0_wp
774	tmp_agent%speed_e_y = 0.0_wp
775	tmp_agent%speed_des = random_normal(desired_speed,&
776	des_sp_sig)
777	tmp_agent%speed_x = 0.0_wp
778	tmp_agent%speed_y = 0.0_wp
779	tmp_agent%thermal_index = 99999.0_wp
780	tmp_agent%x = pos_x
781	tmp_agent%y = pos_y
782	tmp_agent%path_x = -1.0_wp
783	tmp_agent%path_y = -1.0_wp
784	tmp_agent%t_x = - pi
785	tmp_agent%t_y = - pi
786	!
787	!-- Determine the grid indices of the agent position
788	ip = tmp_agent%x * ddx
789	jp = tmp_agent%y * ddy
790	!
791	!-- Give each agent its target
792	IF ( a_rand_target(i) ) THEN
793	!
794	!-- Agent shall receive random target just outside
795	!-- simulated area
796	rn_side_dum = random_function(iran_agent)
797	rn_side = FLOOR(4.*rn_side_dum)
798	IF ( rn_side < 2 ) THEN
799	IF ( rn_side == 0 ) THEN
800	tmp_agent%t_y = -2*dy
801	ELSE
802	tmp_agent%t_y = (ny+3)*dy
803	ENDIF
804	tmp_agent%t_x = random_function(iran_agent) * &
805	(nx+1)*dx
806	ELSE
807	IF ( rn_side == 2 ) THEN
808	tmp_agent%t_x = -2*dx
809	ELSE
810	tmp_agent%t_x = (nx+3)*dx
811	ENDIF
812	tmp_agent%t_y = random_function(iran_agent) * &
813	(ny+1)*dy
814	ENDIF
815	!
816	!-- Agent gets target of her group
817	ELSE
818	tmp_agent%t_x = at_x(i)
819	tmp_agent%t_y = at_y(i)
820	ENDIF
821
822	local_count(jp,ip) = local_count(jp,ip) + 1
823
824	IF ( .NOT. first_stride ) THEN
825	grid_agents(jp,ip)%agents(local_count(jp,ip)) &
826	= tmp_agent
827	ENDIF
828
829	ENDIF
830
831	pos_x = pos_x + adx(i)
832
833	ENDDO xloop
834
835	ENDIF
836
837	pos_y = pos_y + ady(i)
838
839	ENDDO
840
841	ENDDO
842
843	!
844	!-- Allocate or reallocate agents array to new size
845	IF ( first_stride ) THEN
846	DO ip = nxlg, nxrg
847	DO jp = nysg, nyng
848	IF ( phase == PHASE_INIT ) THEN
849	IF ( local_count(jp,ip) > 0 ) THEN
850	alloc_size = MAX( INT( local_count(jp,ip) * &
851	( 1.0_wp + alloc_factor_mas / 100.0_wp ) ), &
852	min_nr_agent )
853	ELSE
854	alloc_size = min_nr_agent
855	ENDIF
856	ALLOCATE(grid_agents(jp,ip)%agents(1:alloc_size))
857	DO n = 1, alloc_size
858	grid_agents(jp,ip)%agents(n) = zero_agent
859	ENDDO
860	ELSEIF ( phase == PHASE_RELEASE ) THEN
861	IF ( local_count(jp,ip) > 0 ) THEN
862	new_size = local_count(jp,ip) + agt_count(jp,ip)
863	alloc_size = MAX( INT( new_size * ( 1.0_wp + &
864	alloc_factor_mas / 100.0_wp ) ), min_nr_agent )
865	IF( alloc_size > SIZE( grid_agents(jp,ip)%agents) ) &
866	THEN
867	CALL mas_eh_realloc_agents_array(ip,jp,alloc_size)
868	ENDIF
869	ENDIF
870	ENDIF
871	ENDDO
872	ENDDO
873	ENDIF
874
875	ENDDO
876
877	local_start = agt_count+1
878	agt_count = local_count
879
880	!
881	!-- Calculate agent IDs
882	DO ip = nxl, nxr
883	DO jp = nys, nyn
884	number_of_agents = agt_count(jp,ip)
885	IF ( number_of_agents <= 0 ) CYCLE
886	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
887
888	DO n = local_start(jp,ip), number_of_agents !only new agents
889
890	agents(n)%id = 10000_idp*2 grid_agents(jp,ip)%id_counter + &
891	10000_idp * jp + ip
892	!
893	!-- Count the number of agents that have been released before
894	grid_agents(jp,ip)%id_counter = grid_agents(jp,ip)%id_counter &
895	+ 1
896
897	ENDDO
898
899	ENDDO
900	ENDDO
901
902	!
903	!-- Add random fluctuation to agent positions.
904	IF ( random_start_position_agents ) THEN
905	DO ip = nxl, nxr
906	DO jp = nys, nyn
907	number_of_agents = agt_count(jp,ip)
908	IF ( number_of_agents <= 0 ) CYCLE
909	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
910	!
911	!-- Move only new agents. Moreover, limit random fluctuation
912	!-- in order to prevent that agents move more than one grid box,
913	!-- which would lead to problems concerning agent exchange
914	!-- between processors in case adx/ady are larger than dx/dy,
915	!-- respectively.
916	DO n = local_start(jp,ip), number_of_agents
917	IF ( asl(agents(n)%group) /= asr(agents(n)%group) ) THEN
918	rand_contr = ( random_function( iran_agent ) - 0.5_wp ) *&
919	adx(agents(n)%group)
920	agents(n)%x = agents(n)%x + &
921	MERGE( rand_contr, SIGN( dx, rand_contr ), &
922	ABS( rand_contr ) < dx &
923	)
924	ENDIF
925	IF ( ass(agents(n)%group) /= asn(agents(n)%group) ) THEN
926	rand_contr = ( random_function( iran_agent ) - 0.5_wp ) *&
927	ady(agents(n)%group)
928	agents(n)%y = agents(n)%y + &
929	MERGE( rand_contr, SIGN( dy, rand_contr ), &
930	ABS( rand_contr ) < dy )
931	ENDIF
932	ENDDO
933	!
934	!-- Delete agents that have been simulated longer than allowed
935	CALL mas_boundary_conds( 'max_sim_time' )
936	!
937	!-- Delete agents that have reached target area
938	CALL mas_boundary_conds( 'target_area' )
939
940	ENDDO
941	ENDDO
942	!
943	!-- Exchange agents between grid cells and processors
944	CALL mas_eh_move_agent
945	CALL mas_eh_exchange_horiz
946
947	ENDIF
948	!
949	!-- In case of random_start_position_agents, delete agents identified by
950	!-- mas_eh_exchange_horiz and mas_boundary_conds. Then sort agents into
951	!-- blocks, which is needed for a fast interpolation of the LES fields
952	!-- on the agent position.
953	CALL mas_ps_sort_in_subboxes
954
955	!
956	!-- Determine the current number of agents
957	number_of_agents = 0
958	DO ip = nxl, nxr
959	DO jp = nys, nyn
960	number_of_agents = number_of_agents + agt_count(jp,ip)
961	ENDDO
962	ENDDO
963	!
964	!-- Calculate the number of agents of the total domain
965	#if defined( __parallel )
966	IF ( collective_wait ) CALL MPI_BARRIER( comm2d, ierr )
967	CALL MPI_ALLREDUCE( number_of_agents, total_number_of_agents, 1, &
968	MPI_INTEGER, MPI_SUM, comm2d, ierr )
969	#else
970	total_number_of_agents = number_of_agents
971	#endif
972
973	RETURN
974
975	END SUBROUTINE mas_create_agent
976
977	!------------------------------------------------------------------------------!
978	! Description:
979	! ------------
980	!> Creates flags that indicate if a gridbox contains edges or corners. These
981	!> flags are used for agents to check if obstacles are close to them.
982	!------------------------------------------------------------------------------!
983	SUBROUTINE mas_create_obstacle_flags
984
985	USE arrays_3d, &
986	ONLY: zw
987
988	IMPLICIT NONE
989
990	INTEGER(iwp) :: agt_size !< Agent size in bytes
991	INTEGER(iwp) :: dummy !< dummy
992	INTEGER(iwp) :: il
993	INTEGER(iwp) :: jl
994
995	ALLOCATE(obstacle_flags(nysg:nyng,nxlg:nxrg))
996
997	obstacle_flags = 0
998
999	DO il = nxlg, nxrg
1000	DO jl = nysg, nyng
1001	!
1002	!-- North edge
1003	IF ( jl < nyng ) THEN
1004	IF ( ( top_top_s(jl,il) - top_top_s(jl+1,il) ) > 1 .AND. &
1005	( zw( top_top_w(jl,il) ) - &
1006	zw( top_top_w(jl+1,il) ) ) > .51_wp ) &
1007	THEN
1008	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 0 )
1009	ENDIF
1010	ENDIF
1011	!
1012	!-- North right corner
1013	IF ( jl < nyng .AND. il < nxrg ) THEN
1014	IF ( ( top_top_s(jl,il) - top_top_s(jl+1,il) ) > 1 .AND. &
1015	( top_top_s(jl,il) - top_top_s(jl+1,il+1) ) > 1 .AND. &
1016	( top_top_s(jl,il) - top_top_s(jl,il+1) ) > 1 .AND. &
1017	( zw( top_top_w(jl,il) ) - &
1018	zw( top_top_w(jl+1,il+1) ) ) > .51_wp ) &
1019	THEN
1020	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 1 )
1021	ENDIF
1022	ENDIF
1023	!
1024	!-- Right edge
1025	IF ( il < nxrg ) THEN
1026	IF ( ( top_top_s(jl,il) - top_top_s(jl,il+1) ) > 1 .AND. &
1027	( zw( top_top_w(jl,il) ) - &
1028	zw( top_top_w(jl,il+1) ) ) > .51_wp ) &
1029	THEN
1030	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 2 )
1031	ENDIF
1032	ENDIF
1033	!
1034	!-- South right corner
1035	IF ( jl > nysg .AND. il < nxrg ) THEN
1036	IF ( ( top_top_s(jl,il) - top_top_s(jl,il+1) ) > 1 .AND. &
1037	( top_top_s(jl,il) - top_top_s(jl-1,il+1) ) > 1 .AND. &
1038	( top_top_s(jl,il) - top_top_s(jl-1,il) ) > 1 .AND. &
1039	( zw(top_top_w(jl,il)) - &
1040	zw( top_top_w(jl-1,il+1) ) ) > .51_wp ) &
1041	THEN
1042	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 3 )
1043	ENDIF
1044	ENDIF
1045	!
1046	!-- South edge
1047	IF ( jl > nysg ) THEN
1048	IF ( ( top_top_s(jl,il) - top_top_s(jl-1,il) ) > 1 .AND. &
1049	( zw( top_top_w(jl,il) ) - &
1050	zw( top_top_w(jl-1,il) ) ) > .51_wp ) &
1051	THEN
1052	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 4 )
1053	ENDIF
1054	ENDIF
1055	!
1056	!-- South left corner
1057	IF ( jl > nysg .AND. il > nxlg ) THEN
1058	IF ( ( top_top_s(jl,il) - top_top_s(jl-1,il) ) > 1 .AND. &
1059	( top_top_s(jl,il) - top_top_s(jl-1,il-1) ) > 1 .AND. &
1060	( top_top_s(jl,il) - top_top_s(jl,il-1) ) > 1 .AND. &
1061	( zw( top_top_w(jl,il) ) - &
1062	zw(top_top_w(jl-1,il-1) ) ) > .51_wp ) &
1063	THEN
1064	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 5 )
1065	ENDIF
1066	ENDIF
1067	!
1068	!-- Left edge
1069	IF ( il > nxlg ) THEN
1070	IF ( ( top_top_s(jl,il) - top_top_s(jl,il-1) ) > 1 .AND. &
1071	( zw(top_top_w(jl,il) ) - &
1072	zw(top_top_w(jl,il-1) ) ) > .51_wp ) &
1073	THEN
1074	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 6 )
1075	ENDIF
1076	ENDIF
1077	!
1078	!-- North left corner
1079	IF ( jl < nyng .AND. il > nxlg ) THEN
1080	IF ( ( top_top_s(jl,il) - top_top_s(jl,il-1) ) > 1 .AND. &
1081	( top_top_s(jl,il) - top_top_s(jl+1,il-1) ) > 1 .AND. &
1082	( top_top_s(jl,il) - top_top_s(jl+1,il) ) > 1 .AND. &
1083	( zw( top_top_w(jl,il) ) - &
1084	zw( top_top_w(jl+1,il-1) ) ) > .51_wp ) &
1085	THEN
1086	obstacle_flags(jl,il) = IBSET( obstacle_flags(jl,il), 7 )
1087	ENDIF
1088	ENDIF
1089
1090	ENDDO
1091	ENDDO
1092
1093	END SUBROUTINE mas_create_obstacle_flags
1094
1095	!------------------------------------------------------------------------------!
1096	! Description:
1097	! ------------
1098	!> Write agent data in netCDF format
1099	!------------------------------------------------------------------------------!
1100	SUBROUTINE mas_data_output_agents( ftest )
1101
1102	USE control_parameters, &
1103	ONLY: agt_time_count
1104
1105	USE netcdf_interface, &
1106	ONLY: nc_stat, id_set_agt, id_var_time_agt, id_var_rnoa_agt, &
1107	id_var_agt, netcdf_handle_error
1108
1109	USE pegrid
1110
1111	#if defined( __netcdf )
1112	USE NETCDF
1113	#endif
1114
1115	IMPLICIT NONE
1116
1117	INTEGER(iwp) :: agt_size !< Agent size in bytes
1118	INTEGER(iwp) :: dummy !< dummy
1119	INTEGER(iwp) :: ip !< counter (x)
1120	INTEGER(iwp) :: jp !< counter (y)
1121	INTEGER(iwp) :: n !< counter (number of PEs)
1122	INTEGER(iwp) :: noa !< number of agents
1123	INTEGER(iwp) :: noa_rcv !< received number of agents
1124	INTEGER(iwp) :: out_noa !< number of agents for output
1125
1126	INTEGER(iwp), DIMENSION(0:numprocs-1) :: noa_arr !< number of agents on each PE
1127
1128	TYPE(agent_type), DIMENSION(:), ALLOCATABLE, TARGET :: trf_agents !< all agents on current PE
1129	TYPE(agent_type), DIMENSION(:), ALLOCATABLE, TARGET :: out_agents !< all agents in entire domain
1130	LOGICAL, INTENT (INOUT) :: ftest
1131
1132	CALL cpu_log( log_point_s(17), 'mas_data_output', 'start' )
1133	!
1134	!-- Get total number of agents and put all agents on one PE in one array
1135	noa = 0
1136	DO ip = nxl, nxr
1137	DO jp = nys, nyn
1138	noa = noa + agt_count(jp,ip)
1139	ENDDO
1140	ENDDO
1141	IF(noa > 0) THEN
1142	ALLOCATE(trf_agents(1:noa))
1143	dummy = 1
1144	DO ip = nxl, nxr
1145	DO jp = nys, nyn
1146	IF ( agt_count(jp,ip) == 0 ) CYCLE
1147	agents => grid_agents(jp,ip)%agents(1:agt_count(jp,ip))
1148	trf_agents(dummy:(dummy-1+agt_count(jp,ip))) = agents
1149	dummy = dummy + agt_count(jp,ip)
1150	ENDDO
1151	ENDDO
1152	ENDIF
1153	!
1154	!-- Gather all agents on PE0 for output
1155	CALL MPI_BARRIER( comm2d, ierr )
1156	IF ( myid == 0 ) THEN
1157	noa_arr(0) = noa
1158	!
1159	!-- Receive data from all other PEs.
1160	DO n = 1, numprocs-1
1161	CALL MPI_RECV( noa_arr(n), 1, MPI_INTEGER, &
1162	n, 0, comm2d, status, ierr )
1163	ENDDO
1164	ELSE
1165	CALL MPI_SEND( noa, 1, MPI_INTEGER, 0, 0, comm2d, ierr )
1166	ENDIF
1167	CALL MPI_BARRIER( comm2d, ierr )
1168	agt_size = C_SIZEOF(zero_agent)
1169	IF ( myid == 0 ) THEN
1170	!
1171	!-- Receive data from all other PEs.
1172	out_noa = SUM(noa_arr)
1173	IF ( out_noa > 0 ) THEN
1174	ALLOCATE( out_agents(1:out_noa) )
1175	IF ( noa > 0 ) THEN
1176	out_agents(1:noa) = trf_agents
1177	ENDIF
1178	noa_rcv = noa
1179	DO n = 1, numprocs-1
1180	IF ( noa_arr(n) > 0 ) THEN
1181	CALL MPI_RECV( out_agents(noa_rcv+1), noa_arr(n)*agt_size, &
1182	MPI_BYTE, n, 0, comm2d, status, ierr )
1183	noa_rcv = noa_rcv + noa_arr(n)
1184	ENDIF
1185	ENDDO
1186	ELSE
1187	ALLOCATE( out_agents(1:2) )
1188	out_agents = zero_agent
1189	out_noa = 2
1190	ENDIF
1191	ELSE
1192	IF ( noa > 0 ) THEN
1193	CALL MPI_SEND( trf_agents(1), noa*agt_size, MPI_BYTE, 0, 0, &
1194	comm2d, ierr )
1195	ENDIF
1196	ENDIF
1197	!
1198	!-- A barrier has to be set, because otherwise some PEs may
1199	!-- proceed too fast so that PE0 may receive wrong data on
1200	!-- tag 0
1201	CALL MPI_BARRIER( comm2d, ierr )
1202	IF ( myid == 0 ) THEN
1203	agents=>out_agents
1204
1205
1206	#if defined( __netcdf )
1207
1208	!-- Output in netCDF format
1209	IF ( ftest ) CALL check_open( 118 )
1210
1211	!
1212	!-- Update the NetCDF time axis
1213	agt_time_count = agt_time_count + 1
1214
1215	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_time_agt, &
1216	(/ simulated_time /), &
1217	start = (/ agt_time_count /), count = (/ 1 /) )
1218	CALL netcdf_handle_error( 'mas_data_output_agents', 1 )
1219
1220	!
1221	!-- Output all agent attributes
1222	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(1), agents%x, &
1223	start = (/ 1, agt_time_count /), &
1224	count = (/ out_noa /) )
1225	CALL netcdf_handle_error( 'mas_data_output_agents', 3 )
1226
1227	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(2), agents%y, &
1228	start = (/ 1, agt_time_count /), &
1229	count = (/ out_noa /) )
1230	CALL netcdf_handle_error( 'mas_data_output_agents', 4 )
1231
1232	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(3), agents%windspeed, &
1233	start = (/ 1, agt_time_count /), &
1234	count = (/ out_noa /) )
1235	CALL netcdf_handle_error( 'mas_data_output_agents', 5 )
1236
1237	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(4), agents%t, &
1238	start = (/ 1, agt_time_count /), &
1239	count = (/ out_noa /) )
1240	CALL netcdf_handle_error( 'mas_data_output_agents', 6 )
1241
1242	nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(5), agents%group, &
1243	start = (/ 1, agt_time_count /), &
1244	count = (/ out_noa /) )
1245	CALL netcdf_handle_error( 'mas_data_output_agents', 7 )
1246
1247	! nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(6), agents%pm10, &
1248	! start = (/ 1, agt_time_count /), &
1249	! count = (/ out_noa /) )
1250	! CALL netcdf_handle_error( 'mas_data_output_agents', 8 )
1251	!
1252	! nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(7), agents%pm25, &
1253	! start = (/ 1, agt_time_count /), &
1254	! count = (/ out_noa /) )
1255	! CALL netcdf_handle_error( 'mas_data_output_agents', 9 )
1256	!
1257	! nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(8), agents%therm_comf,&
1258	! start = (/ 1, agt_time_count /), &
1259	! count = (/ out_noa /) )
1260	!
1261	! nc_stat = NF90_PUT_VAR( id_set_agt, id_var_agt(9), agents%uv, &
1262	! start = (/ 1, agt_time_count /), &
1263	! count = (/ out_noa /) )
1264	CALL netcdf_handle_error( 'mas_data_output_agents', 10 )
1265
1266	#endif
1267
1268	DEALLOCATE(out_agents)
1269	ENDIF
1270
1271	CALL cpu_log( log_point_s(17), 'mas_data_output', 'stop' )
1272
1273	END SUBROUTINE mas_data_output_agents
1274
1275	!------------------------------------------------------------------------------!
1276	! Description:
1277	! ------------
1278	!> If an agent moves from one processor to another, this subroutine moves
1279	!> the corresponding elements from the agent arrays of the old grid cells
1280	!> to the agent arrays of the new grid cells.
1281	!------------------------------------------------------------------------------!
1282	SUBROUTINE mas_eh_add_agents_to_gridcell (agent_array)
1283
1284	IMPLICIT NONE
1285
1286	INTEGER(iwp) :: aindex !< dummy argument for new number of agents per grid box
1287	INTEGER(iwp) :: ip !< grid index (x) of agent
1288	INTEGER(iwp) :: jp !< grid index (x) of agent
1289	INTEGER(iwp) :: n !< index variable of agent
1290
1291	LOGICAL :: pack_done !< flag to indicate that packing is done
1292
1293	TYPE(agent_type), DIMENSION(:), INTENT(IN) :: agent_array !< new agents in a grid box
1294	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: temp_ns !< temporary agent array for reallocation
1295
1296	pack_done = .FALSE.
1297
1298	DO n = 1, SIZE(agent_array)
1299
1300	IF ( .NOT. agent_array(n)%agent_mask ) CYCLE
1301
1302	ip = agent_array(n)%x * ddx
1303	jp = agent_array(n)%y * ddy
1304
1305	IF ( ip >= nxl .AND. ip <= nxr .AND. &
1306	jp >= nys .AND. jp <= nyn ) &
1307	THEN ! agent stays on processor
1308	number_of_agents = agt_count(jp,ip)
1309	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1310
1311	aindex = agt_count(jp,ip)+1
1312	IF( aindex > SIZE(grid_agents(jp,ip)%agents) ) THEN
1313	IF ( pack_done ) THEN
1314	CALL mas_eh_realloc_agents_array (ip,jp)
1315	ELSE
1316	CALL mas_ps_pack
1317	agt_count(jp,ip) = number_of_agents
1318	aindex = agt_count(jp,ip)+1
1319	IF ( aindex > SIZE(grid_agents(jp,ip)%agents) ) THEN
1320	CALL mas_eh_realloc_agents_array (ip,jp)
1321	ENDIF
1322	pack_done = .TRUE.
1323	ENDIF
1324	ENDIF
1325	grid_agents(jp,ip)%agents(aindex) = agent_array(n)
1326	agt_count(jp,ip) = aindex
1327	ELSE
1328	IF ( jp <= nys - 1 ) THEN
1329	nr_move_south = nr_move_south+1
1330	!
1331	!-- Before agent information is swapped to exchange-array, check
1332	!-- if enough memory is allocated. If required, reallocate exchange
1333	!-- array.
1334	IF ( nr_move_south > SIZE(move_also_south) ) THEN
1335	!
1336	!-- At first, allocate further temporary array to swap agent
1337	!-- information.
1338	ALLOCATE( temp_ns(SIZE(move_also_south)+NR_2_direction_move))
1339	temp_ns(1:nr_move_south-1) = move_also_south &
1340	(1:nr_move_south-1)
1341	DEALLOCATE( move_also_south )
1342	ALLOCATE( move_also_south(SIZE(temp_ns)) )
1343	move_also_south(1:nr_move_south-1) = temp_ns &
1344	(1:nr_move_south-1)
1345	DEALLOCATE( temp_ns )
1346
1347	ENDIF
1348
1349	move_also_south(nr_move_south) = agent_array(n)
1350
1351	IF ( jp == -1 ) THEN
1352	!
1353	!-- Apply boundary condition along y
1354	IF ( ibc_mas_ns == 0 ) THEN
1355	move_also_south(nr_move_south)%y = &
1356	move_also_south(nr_move_south)%y &
1357	+ ( ny + 1 ) * dy
1358	move_also_south(nr_move_south)%origin_y = &
1359	move_also_south(nr_move_south)%origin_y &
1360	+ ( ny + 1 ) * dy
1361	ELSEIF ( ibc_mas_ns == 1 ) THEN
1362	!
1363	!-- Agent absorption
1364	move_also_south(nr_move_south)%agent_mask = .FALSE.
1365	deleted_agents = deleted_agents + 1
1366
1367	ENDIF
1368	ENDIF
1369	ELSEIF ( jp >= nyn+1 ) THEN
1370	nr_move_north = nr_move_north+1
1371	!
1372	!-- Before agent information is swapped to exchange-array, check
1373	!-- if enough memory is allocated. If required, reallocate exchange
1374	!-- array.
1375	IF ( nr_move_north > SIZE(move_also_north) ) THEN
1376	!
1377	!-- At first, allocate further temporary array to swap agent
1378	!-- information.
1379	ALLOCATE( temp_ns(SIZE(move_also_north)+NR_2_direction_move))
1380	temp_ns(1:nr_move_north-1) = &
1381	move_also_south(1:nr_move_north-1)
1382	DEALLOCATE( move_also_north )
1383	ALLOCATE( move_also_north(SIZE(temp_ns)) )
1384	move_also_north(1:nr_move_north-1) = &
1385	temp_ns(1:nr_move_north-1)
1386	DEALLOCATE( temp_ns )
1387
1388	ENDIF
1389
1390	move_also_north(nr_move_north) = agent_array(n)
1391	IF ( jp == ny+1 ) THEN
1392	!
1393	!-- Apply boundary condition along y
1394	IF ( ibc_mas_ns == 0 ) THEN
1395
1396	move_also_north(nr_move_north)%y = &
1397	move_also_north(nr_move_north)%y &
1398	- ( ny + 1 ) * dy
1399	move_also_north(nr_move_north)%origin_y = &
1400	move_also_north(nr_move_north)%origin_y &
1401	- ( ny + 1 ) * dy
1402	ELSEIF ( ibc_mas_ns == 1 ) THEN
1403	!
1404	!-- Agent absorption
1405	move_also_north(nr_move_north)%agent_mask = .FALSE.
1406	deleted_agents = deleted_agents + 1
1407
1408	ENDIF
1409	ENDIF
1410	ENDIF
1411	ENDIF
1412	ENDDO
1413
1414	RETURN
1415
1416	END SUBROUTINE mas_eh_add_agents_to_gridcell
1417
1418	!------------------------------------------------------------------------------!
1419	! Description:
1420	! ------------
1421	!> After ghost layer agents have been received from neighboring PEs, this
1422	!> subroutine sorts them into the corresponding grid cells
1423	!------------------------------------------------------------------------------!
1424	SUBROUTINE mas_eh_add_ghost_agents_to_gridcell (agent_array)
1425
1426	IMPLICIT NONE
1427
1428	INTEGER(iwp) :: ip !< grid index (x) of agent
1429	INTEGER(iwp) :: jp !< grid index (x) of agent
1430	INTEGER(iwp) :: n !< index variable of agent
1431	INTEGER(iwp) :: aindex !< dummy argument for new number of agents per grid box
1432
1433	LOGICAL :: pack_done !< flag to indicate that packing is done
1434
1435	TYPE(agent_type), DIMENSION(:), INTENT(IN) :: agent_array !< new agents in a grid box
1436	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: temp_ns !< temporary agent array for reallocation
1437
1438	pack_done = .FALSE.
1439
1440	DO n = 1, SIZE(agent_array)
1441
1442	IF ( .NOT. agent_array(n)%agent_mask ) CYCLE
1443
1444	ip = agent_array(n)%x * ddx
1445	jp = agent_array(n)%y * ddy
1446
1447	IF ( ip < nxl .OR. ip > nxr .OR. jp < nys .OR. jp > nyn ) THEN
1448	number_of_agents = agt_count(jp,ip)
1449	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1450
1451	aindex = agt_count(jp,ip)+1
1452	IF( aindex > SIZE(grid_agents(jp,ip)%agents) ) THEN
1453	IF ( pack_done ) THEN
1454	CALL mas_eh_realloc_agents_array (ip,jp)
1455	ELSE
1456	CALL mas_ps_pack
1457	agt_count(jp,ip) = number_of_agents
1458	aindex = agt_count(jp,ip)+1
1459	IF ( aindex > SIZE(grid_agents(jp,ip)%agents) ) THEN
1460	CALL mas_eh_realloc_agents_array (ip,jp)
1461	ENDIF
1462	pack_done = .TRUE.
1463	ENDIF
1464	ENDIF
1465	grid_agents(jp,ip)%agents(aindex) = agent_array(n)
1466	agt_count(jp,ip) = aindex
1467	ENDIF
1468	ENDDO
1469	END SUBROUTINE mas_eh_add_ghost_agents_to_gridcell
1470
1471	!------------------------------------------------------------------------------!
1472	! Description:
1473	! ------------
1474	!> Resizing of agent arrays
1475	!------------------------------------------------------------------------------!
1476	SUBROUTINE mas_eh_dealloc_agents_array
1477
1478	IMPLICIT NONE
1479
1480	INTEGER(iwp) :: i !< grid index (x) of agent
1481	INTEGER(iwp) :: j !< grid index (y) of agent
1482	INTEGER(iwp) :: old_size !< old array size
1483	INTEGER(iwp) :: new_size !< new array size
1484	INTEGER(iwp) :: noa !< number of agents
1485
1486	LOGICAL :: dealloc !< flag that indicates if reallocation is necessary
1487
1488	TYPE(agent_type), DIMENSION(10) :: tmp_agents_s !< temporary static agent array
1489
1490	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: tmp_agents_d !< temporary dynamic agent array
1491
1492	DO i = nxlg, nxrg
1493	DO j = nysg, nyng
1494	!
1495	!-- Determine number of active agents
1496	noa = agt_count(j,i)
1497	!
1498	!-- Determine allocated memory size
1499	old_size = SIZE( grid_agents(j,i)%agents )
1500	!
1501	!-- Check for large unused memory
1502	dealloc = ( ( noa < min_nr_agent .AND. old_size > min_nr_agent ) &
1503	.OR. ( noa > min_nr_agent .AND. old_size - noa * &
1504	( 1.0_wp + 0.01_wp * alloc_factor_mas ) > 0.0_wp ) )
1505	!
1506	!-- If large unused memory was found, resize the corresponding array
1507	IF ( dealloc ) THEN
1508	IF ( noa < min_nr_agent ) THEN
1509	new_size = min_nr_agent
1510	ELSE
1511	new_size = INT( noa * ( 1.0_wp + &
1512	0.01_wp * alloc_factor_mas ) )
1513	ENDIF
1514
1515	IF ( noa <= 10 ) THEN
1516
1517	tmp_agents_s(1:noa) = grid_agents(j,i)%agents(1:noa)
1518
1519	DEALLOCATE(grid_agents(j,i)%agents)
1520	ALLOCATE(grid_agents(j,i)%agents(1:new_size))
1521
1522	grid_agents(j,i)%agents(1:noa) = tmp_agents_s(1:noa)
1523	grid_agents(j,i)%agents(noa+1:new_size) = zero_agent
1524
1525	ELSE
1526
1527	ALLOCATE(tmp_agents_d(noa))
1528	tmp_agents_d(1:noa) = grid_agents(j,i)%agents(1:noa)
1529
1530	DEALLOCATE(grid_agents(j,i)%agents)
1531	ALLOCATE(grid_agents(j,i)%agents(new_size))
1532
1533	grid_agents(j,i)%agents(1:noa) = tmp_agents_d(1:noa)
1534	grid_agents(j,i)%agents(noa+1:new_size) = zero_agent
1535
1536	DEALLOCATE(tmp_agents_d)
1537
1538	ENDIF
1539
1540	ENDIF
1541	ENDDO
1542	ENDDO
1543
1544	END SUBROUTINE mas_eh_dealloc_agents_array
1545
1546	!------------------------------------------------------------------------------!
1547	! Description:
1548	! ------------
1549	!> Exchange between subdomains.
1550	!> As soon as one agent has moved beyond the boundary of the domain, it
1551	!> is included in the relevant transfer arrays and marked for subsequent
1552	!> deletion on this PE.
1553	!> First sweep for crossings in x direction. Find out first the number of
1554	!> agents to be transferred and allocate temporary arrays needed to store
1555	!> them.
1556	!> For a one-dimensional decomposition along y, no transfer is necessary,
1557	!> because the agent remains on the PE, but the agent coordinate has to
1558	!> be adjusted.
1559	!------------------------------------------------------------------------------!
1560	SUBROUTINE mas_eh_exchange_horiz
1561
1562	IMPLICIT NONE
1563
1564	INTEGER(iwp) :: i !< grid index (x) of agent positition
1565	INTEGER(iwp) :: ip !< index variable along x
1566	INTEGER(iwp) :: j !< grid index (y) of agent positition
1567	INTEGER(iwp) :: jp !< index variable along y
1568	INTEGER(iwp) :: kp !< index variable along z
1569	INTEGER(iwp) :: n !< agent index variable
1570	INTEGER(iwp) :: par_size !< Agent size in bytes
1571	INTEGER(iwp) :: trla_count !< number of agents send to left PE
1572	INTEGER(iwp) :: trla_count_recv !< number of agents receive from right PE
1573	INTEGER(iwp) :: trna_count !< number of agents send to north PE
1574	INTEGER(iwp) :: trna_count_recv !< number of agents receive from south PE
1575	INTEGER(iwp) :: trra_count !< number of agents send to right PE
1576	INTEGER(iwp) :: trra_count_recv !< number of agents receive from left PE
1577	INTEGER(iwp) :: trsa_count !< number of agents send to south PE
1578	INTEGER(iwp) :: trsa_count_recv !< number of agents receive from north PE
1579
1580	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: rvla !< agents received from right PE
1581	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: rvna !< agents received from south PE
1582	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: rvra !< agents received from left PE
1583	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: rvsa !< agents received from north PE
1584	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: trla !< agents send to left PE
1585	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: trna !< agents send to north PE
1586	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: trra !< agents send to right PE
1587	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: trsa !< agents send to south PE
1588
1589	CALL cpu_log( log_point_s(18), 'mas_eh_exchange_horiz', 'start' )
1590
1591	#if defined( __parallel )
1592
1593	!
1594	!-- Exchange between subdomains.
1595	!-- As soon as one agent has moved beyond the boundary of the domain, it
1596	!-- is included in the relevant transfer arrays and marked for subsequent
1597	!-- deletion on this PE.
1598	!-- First sweep for crossings in x direction. Find out first the number of
1599	!-- agents to be transferred and allocate temporary arrays needed to store
1600	!-- them.
1601	!-- For a one-dimensional decomposition along y, no transfer is necessary,
1602	!-- because the agent remains on the PE, but the agent coordinate has to
1603	!-- be adjusted.
1604	trla_count = 0
1605	trra_count = 0
1606
1607	trla_count_recv = 0
1608	trra_count_recv = 0
1609
1610	IF ( pdims(1) /= 1 ) THEN
1611	!
1612	!-- First calculate the storage necessary for sending and receiving the data.
1613	!-- Compute only first (nxl) and last (nxr) loop iterration.
1614	DO ip = nxl, nxr, nxr - nxl
1615	DO jp = nys, nyn
1616
1617	number_of_agents = agt_count(jp,ip)
1618	IF ( number_of_agents <= 0 ) CYCLE
1619	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1620	DO n = 1, number_of_agents
1621	IF ( agents(n)%agent_mask ) THEN
1622	i = agents(n)%x * ddx
1623	!
1624	!-- Above calculation does not work for indices less than zero
1625	IF ( agents(n)%x < 0.0_wp ) i = -1
1626
1627	IF ( i < nxl ) THEN
1628	trla_count = trla_count + 1
1629	ELSEIF ( i > nxr ) THEN
1630	trra_count = trra_count + 1
1631	ENDIF
1632	ENDIF
1633	ENDDO
1634
1635	ENDDO
1636	ENDDO
1637
1638	IF ( trla_count == 0 ) trla_count = 1
1639	IF ( trra_count == 0 ) trra_count = 1
1640
1641	ALLOCATE( trla(trla_count), trra(trra_count) )
1642
1643	trla = zero_agent
1644	trra = zero_agent
1645
1646	trla_count = 0
1647	trra_count = 0
1648
1649	ENDIF
1650	!
1651	!-- Compute only first (nxl) and last (nxr) loop iterration
1652	DO ip = nxl, nxr, nxr-nxl
1653	DO jp = nys, nyn
1654	number_of_agents = agt_count(jp,ip)
1655	IF ( number_of_agents <= 0 ) CYCLE
1656	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1657	DO n = 1, number_of_agents
1658	!
1659	!-- Only those agents that have not been marked as 'deleted' may
1660	!-- be moved.
1661	IF ( agents(n)%agent_mask ) THEN
1662
1663	i = agents(n)%x * ddx
1664	!
1665	!-- Above calculation does not work for indices less than zero
1666	IF ( agents(n)%x < 0.0_wp ) i = -1
1667
1668	IF ( i < nxl ) THEN
1669	IF ( i < 0 ) THEN
1670	!
1671	!-- Apply boundary condition along x
1672	IF ( ibc_mas_lr == 0 ) THEN
1673	!
1674	!-- Cyclic condition
1675	IF ( pdims(1) == 1 ) THEN
1676	agents(n)%x = ( nx + 1 ) * dx + &
1677	agents(n)%x
1678	agents(n)%origin_x = ( nx + 1 ) * dx + &
1679	agents(n)%origin_x
1680	ELSE
1681	trla_count = trla_count + 1
1682	trla(trla_count) = agents(n)
1683	trla(trla_count)%x = ( nx + 1 ) * dx + &
1684	trla(trla_count)%x
1685	trla(trla_count)%origin_x = &
1686	trla(trla_count)%origin_x + &
1687	( nx + 1 ) * dx
1688	agents(n)%agent_mask = .FALSE.
1689	deleted_agents = deleted_agents + 1
1690
1691	IF ( trla(trla_count)%x >= &
1692	(nx + 1)* dx - 1.0E-12_wp ) &
1693	THEN
1694	trla(trla_count)%x = trla(trla_count)%x - &
1695	1.0E-10_wp
1696	trla(trla_count)%origin_x = &
1697	trla(trla_count)%origin_x - 1
1698	ENDIF
1699
1700	ENDIF
1701
1702	ELSEIF ( ibc_mas_lr == 1 ) THEN
1703	!
1704	!-- Agent absorption
1705	agents(n)%agent_mask = .FALSE.
1706	deleted_agents = deleted_agents + 1
1707
1708	ENDIF
1709	ELSE
1710	!
1711	!-- Store agent data in the transfer array, which will be
1712	!-- send to the neighbouring PE
1713	trla_count = trla_count + 1
1714	trla(trla_count) = agents(n)
1715	agents(n)%agent_mask = .FALSE.
1716	deleted_agents = deleted_agents + 1
1717
1718	ENDIF
1719
1720	ELSEIF ( i > nxr ) THEN
1721	IF ( i > nx ) THEN
1722	!
1723	!-- Apply boundary condition along x
1724	IF ( ibc_mas_lr == 0 ) THEN
1725	!
1726	!-- Cyclic condition
1727	IF ( pdims(1) == 1 ) THEN
1728	agents(n)%x = agents(n)%x - ( nx + 1 ) * dx
1729	agents(n)%origin_x = agents(n)%origin_x - &
1730	( nx + 1 ) * dx
1731	ELSE
1732	trra_count = trra_count + 1
1733	trra(trra_count) = agents(n)
1734	trra(trra_count)%x = trra(trra_count)%x - &
1735	( nx + 1 ) * dx
1736	trra(trra_count)%origin_x = &
1737	trra(trra_count)%origin_x - &
1738	( nx + 1 ) * dx
1739	agents(n)%agent_mask = .FALSE.
1740	deleted_agents = deleted_agents + 1
1741
1742	ENDIF
1743
1744	ELSEIF ( ibc_mas_lr == 1 ) THEN
1745	!
1746	!-- Agent absorption
1747	agents(n)%agent_mask = .FALSE.
1748	deleted_agents = deleted_agents + 1
1749
1750	ENDIF
1751	ELSE
1752	!
1753	!-- Store agent data in the transfer array, which will be send
1754	!-- to the neighbouring PE
1755	trra_count = trra_count + 1
1756	trra(trra_count) = agents(n)
1757	agents(n)%agent_mask = .FALSE.
1758	deleted_agents = deleted_agents + 1
1759
1760	ENDIF
1761
1762	ENDIF
1763	ENDIF
1764
1765	ENDDO
1766	ENDDO
1767	ENDDO
1768
1769	!
1770	!-- Allocate arrays required for north-south exchange, as these
1771	!-- are used directly after agents are exchange along x-direction.
1772	ALLOCATE( move_also_north(1:NR_2_direction_move) )
1773	ALLOCATE( move_also_south(1:NR_2_direction_move) )
1774
1775	nr_move_north = 0
1776	nr_move_south = 0
1777	!
1778	!-- Send left boundary, receive right boundary (but first exchange how many
1779	!-- and chec if agent storage must be extended)
1780	IF ( pdims(1) /= 1 ) THEN
1781
1782	CALL MPI_SENDRECV( trla_count, 1, MPI_INTEGER, pleft, 0, &
1783	trra_count_recv, 1, MPI_INTEGER, pright, 0, &
1784	comm2d, status, ierr )
1785
1786	ALLOCATE(rvra(MAX(1,trra_count_recv)))
1787	!
1788	!-- This MPI_SENDRECV should work even with odd mixture on 32 and 64 Bit
1789	!-- variables in structure agent_type (due to the calculation of par_size)
1790	par_size = C_SIZEOF(trla(1))
1791	CALL MPI_SENDRECV( trla, max(1,trla_count)*par_size, MPI_BYTE, pleft,&
1792	1, rvra, max(1,trra_count_recv)*par_size, MPI_BYTE, pright,&
1793	1, comm2d, status, ierr )
1794
1795	IF ( trra_count_recv > 0 ) THEN
1796	CALL mas_eh_add_agents_to_gridcell(rvra(1:trra_count_recv))
1797	ENDIF
1798
1799	DEALLOCATE(rvra)
1800
1801	!
1802	!-- Send right boundary, receive left boundary
1803	CALL MPI_SENDRECV( trra_count, 1, MPI_INTEGER, pright, 0, &
1804	trla_count_recv, 1, MPI_INTEGER, pleft, 0, &
1805	comm2d, status, ierr )
1806
1807	ALLOCATE(rvla(MAX(1,trla_count_recv)))
1808	!
1809	!-- This MPI_SENDRECV should work even with odd mixture on 32 and 64 Bit
1810	!-- variables in structure agent_type (due to the calculation of par_size)
1811	par_size = C_SIZEOF(trra(1))
1812	CALL MPI_SENDRECV( trra, max(1,trra_count)*par_size, MPI_BYTE, &
1813	pright, 1, rvla, &
1814	max(1,trla_count_recv)*par_size, MPI_BYTE, &
1815	pleft, 1, comm2d, status, ierr )
1816
1817	IF ( trla_count_recv > 0 ) THEN
1818	CALL mas_eh_add_agents_to_gridcell(rvla(1:trla_count_recv))
1819	ENDIF
1820
1821	DEALLOCATE( rvla )
1822	DEALLOCATE( trla, trra )
1823
1824	ENDIF
1825
1826	!
1827	!-- Check whether agents have crossed the boundaries in y direction. Note
1828	!-- that this case can also apply to agents that have just been received
1829	!-- from the adjacent right or left PE.
1830	!-- Find out first the number of agents to be transferred and allocate
1831	!-- temporary arrays needed to store them.
1832	!-- For a one-dimensional decomposition along y, no transfer is necessary,
1833	!-- because the agent remains on the PE.
1834	trsa_count = nr_move_south
1835	trna_count = nr_move_north
1836
1837	trsa_count_recv = 0
1838	trna_count_recv = 0
1839
1840	IF ( pdims(2) /= 1 ) THEN
1841	!
1842	!-- First calculate the storage necessary for sending and receiving the
1843	!-- data
1844	DO ip = nxl, nxr
1845	DO jp = nys, nyn, nyn-nys !compute only first (nys) and last (nyn) loop iterration
1846	number_of_agents = agt_count(jp,ip)
1847	IF ( number_of_agents <= 0 ) CYCLE
1848	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1849	DO n = 1, number_of_agents
1850	IF ( agents(n)%agent_mask ) THEN
1851	j = agents(n)%y * ddy
1852	!
1853	!-- Above calculation does not work for indices less than zero
1854	IF ( agents(n)%y < 0.0_wp ) j = -1
1855
1856	IF ( j < nys ) THEN
1857	trsa_count = trsa_count + 1
1858	ELSEIF ( j > nyn ) THEN
1859	trna_count = trna_count + 1
1860	ENDIF
1861	ENDIF
1862	ENDDO
1863	ENDDO
1864	ENDDO
1865
1866	IF ( trsa_count == 0 ) trsa_count = 1
1867	IF ( trna_count == 0 ) trna_count = 1
1868
1869	ALLOCATE( trsa(trsa_count), trna(trna_count) )
1870
1871	trsa = zero_agent
1872	trna = zero_agent
1873
1874	trsa_count = nr_move_south
1875	trna_count = nr_move_north
1876
1877	trsa(1:nr_move_south) = move_also_south(1:nr_move_south)
1878	trna(1:nr_move_north) = move_also_north(1:nr_move_north)
1879
1880	ENDIF
1881
1882	DO ip = nxl, nxr
1883	DO jp = nys, nyn, nyn-nys ! compute only first (nys) and last (nyn) loop iterration
1884	number_of_agents = agt_count(jp,ip)
1885	IF ( number_of_agents <= 0 ) CYCLE
1886	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
1887	DO n = 1, number_of_agents
1888	!
1889	!-- Only those agents that have not been marked as 'deleted' may
1890	!-- be moved.
1891	IF ( agents(n)%agent_mask ) THEN
1892
1893	j = agents(n)%y * ddy
1894	!
1895	!-- Above calculation does not work for indices less than zero
1896	IF ( agents(n)%y < 0.0_wp * dy ) j = -1
1897
1898	IF ( j < nys ) THEN
1899	IF ( j < 0 ) THEN
1900	!
1901	!-- Apply boundary condition along y
1902	IF ( ibc_mas_ns == 0 ) THEN
1903	!
1904	!-- Cyclic condition
1905	IF ( pdims(2) == 1 ) THEN
1906	agents(n)%y = ( ny + 1 ) * dy + agents(n)%y
1907	agents(n)%origin_y = ( ny + 1 ) * dy + &
1908	agents(n)%origin_y
1909	ELSE
1910	trsa_count = trsa_count + 1
1911	trsa(trsa_count) = agents(n)
1912	trsa(trsa_count)%y = ( ny + 1 ) * dy + &
1913	trsa(trsa_count)%y
1914	trsa(trsa_count)%origin_y = &
1915	trsa(trsa_count)%origin_y &
1916	+ ( ny + 1 ) * dy
1917	agents(n)%agent_mask = .FALSE.
1918	deleted_agents = deleted_agents + 1
1919
1920	IF ( trsa(trsa_count)%y >= &
1921	(ny+1)* dy - 1.0E-12_wp ) &
1922	THEN
1923	trsa(trsa_count)%y = trsa(trsa_count)%y - &
1924	1.0E-10_wp
1925	trsa(trsa_count)%origin_y = &
1926	trsa(trsa_count)%origin_y - 1
1927	ENDIF
1928
1929	ENDIF
1930
1931	ELSEIF ( ibc_mas_ns == 1 ) THEN
1932	!
1933	!-- Agent absorption
1934	agents(n)%agent_mask = .FALSE.
1935	deleted_agents = deleted_agents + 1
1936
1937	ENDIF
1938	ELSE
1939	!
1940	!-- Store agent data in the transfer array, which will
1941	!-- be send to the neighbouring PE
1942	trsa_count = trsa_count + 1
1943	trsa(trsa_count) = agents(n)
1944	agents(n)%agent_mask = .FALSE.
1945	deleted_agents = deleted_agents + 1
1946
1947	ENDIF
1948
1949	ELSEIF ( j > nyn ) THEN
1950	IF ( j > ny ) THEN
1951	!
1952	!-- Apply boundary condition along y
1953	IF ( ibc_mas_ns == 0 ) THEN
1954	!
1955	!-- Cyclic condition
1956	IF ( pdims(2) == 1 ) THEN
1957	agents(n)%y = agents(n)%y - &
1958	( ny + 1 ) * dy
1959	agents(n)%origin_y = agents(n)%origin_y - &
1960	( ny + 1 ) * dy
1961	ELSE
1962	trna_count = trna_count + 1
1963	trna(trna_count) = agents(n)
1964	trna(trna_count)%y = &
1965	trna(trna_count)%y - ( ny + 1 ) * dy
1966	trna(trna_count)%origin_y = &
1967	trna(trna_count)%origin_y - &
1968	( ny + 1 ) * dy
1969	agents(n)%agent_mask = .FALSE.
1970	deleted_agents = deleted_agents + 1
1971	ENDIF
1972
1973	ELSEIF ( ibc_mas_ns == 1 ) THEN
1974	!
1975	!-- Agent absorption
1976	agents(n)%agent_mask = .FALSE.
1977	deleted_agents = deleted_agents + 1
1978
1979	ENDIF
1980	ELSE
1981	!
1982	!-- Store agent data in the transfer array, which will
1983	!-- be send to the neighbouring PE
1984	trna_count = trna_count + 1
1985	trna(trna_count) = agents(n)
1986	agents(n)%agent_mask = .FALSE.
1987	deleted_agents = deleted_agents + 1
1988
1989	ENDIF
1990
1991	ENDIF
1992	ENDIF
1993	ENDDO
1994	ENDDO
1995	ENDDO
1996
1997	!
1998	!-- Send front boundary, receive back boundary (but first exchange how many
1999	!-- and chec if agent storage must be extended)
2000	IF ( pdims(2) /= 1 ) THEN
2001
2002	CALL MPI_SENDRECV( trsa_count, 1, MPI_INTEGER, psouth, 0, &
2003	trna_count_recv, 1, MPI_INTEGER, pnorth, 0, &
2004	comm2d, status, ierr )
2005
2006	ALLOCATE(rvna(MAX(1,trna_count_recv)))
2007	!
2008	!-- This MPI_SENDRECV should work even with odd mixture on 32 and 64 Bit
2009	!-- variables in structure agent_type (due to the calculation of par_size)
2010	par_size = C_SIZEOF(trsa(1))
2011	CALL MPI_SENDRECV( trsa, trsa_count*par_size, MPI_BYTE, &
2012	psouth, 1, rvna, &
2013	trna_count_recv*par_size, MPI_BYTE, pnorth, 1, &
2014	comm2d, status, ierr )
2015
2016	IF ( trna_count_recv > 0 ) THEN
2017	CALL mas_eh_add_agents_to_gridcell(rvna(1:trna_count_recv))
2018	ENDIF
2019
2020	DEALLOCATE(rvna)
2021
2022	!
2023	!-- Send back boundary, receive front boundary
2024	CALL MPI_SENDRECV( trna_count, 1, MPI_INTEGER, pnorth, 0, &
2025	trsa_count_recv, 1, MPI_INTEGER, psouth, 0, &
2026	comm2d, status, ierr )
2027
2028	ALLOCATE(rvsa(MAX(1,trsa_count_recv)))
2029	!
2030	!-- This MPI_SENDRECV should work even with odd mixture on 32 and 64 Bit
2031	!-- variables in structure agent_type (due to the calculation of par_size)
2032	par_size = C_SIZEOF(trna(1))
2033	CALL MPI_SENDRECV( trna, trna_count*par_size, MPI_BYTE, &
2034	pnorth, 1, rvsa, &
2035	trsa_count_recv*par_size, MPI_BYTE, psouth, 1, &
2036	comm2d, status, ierr )
2037
2038	IF ( trsa_count_recv > 0 ) THEN
2039	CALL mas_eh_add_agents_to_gridcell(rvsa(1:trsa_count_recv))
2040	ENDIF
2041
2042	DEALLOCATE(rvsa)
2043
2044	number_of_agents = number_of_agents + trsa_count_recv
2045
2046	DEALLOCATE( trsa, trna )
2047
2048	ENDIF
2049
2050	DEALLOCATE( move_also_north )
2051	DEALLOCATE( move_also_south )
2052
2053	#else
2054
2055	DO ip = nxl, nxr, nxr-nxl
2056	DO jp = nys, nyn
2057	number_of_agents = agt_count(jp,ip)
2058	IF ( number_of_agents <= 0 ) CYCLE
2059	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
2060	DO n = 1, number_of_agents
2061	!
2062	!-- Apply boundary conditions
2063	IF ( agents(n)%x < 0.0_wp ) THEN
2064
2065	IF ( ibc_mas_lr == 0 ) THEN
2066	!
2067	!-- Cyclic boundary. Relevant coordinate has to be changed.
2068	agents(n)%x = ( nx + 1 ) * dx + agents(n)%x
2069	agents(n)%origin_x = ( nx + 1 ) * dx + &
2070	agents(n)%origin_x
2071	ELSEIF ( ibc_mas_lr == 1 ) THEN
2072	!
2073	!-- Agent absorption
2074	agents(n)%agent_mask = .FALSE.
2075	deleted_agents = deleted_agents + 1
2076	ENDIF
2077
2078	ELSEIF ( agents(n)%x >= ( nx + 1 ) * dx ) THEN
2079
2080	IF ( ibc_mas_lr == 0 ) THEN
2081	!
2082	!-- Cyclic boundary. Relevant coordinate has to be changed.
2083	agents(n)%x = agents(n)%x - ( nx + 1 ) * dx
2084
2085	ELSEIF ( ibc_mas_lr == 1 ) THEN
2086	!
2087	!-- Agent absorption
2088	agents(n)%agent_mask = .FALSE.
2089	deleted_agents = deleted_agents + 1
2090	ENDIF
2091
2092	ENDIF
2093	ENDDO
2094	ENDDO
2095	ENDDO
2096
2097	DO ip = nxl, nxr
2098	DO jp = nys, nyn, nyn-nys
2099	number_of_agents = agt_count(jp,ip)
2100	IF ( number_of_agents <= 0 ) CYCLE
2101	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
2102	DO n = 1, number_of_agents
2103
2104	IF ( agents(n)%y < 0.0_wp ) THEN
2105
2106	IF ( ibc_mas_ns == 0 ) THEN
2107	!
2108	!-- Cyclic boundary. Relevant coordinate has to be changed.
2109	agents(n)%y = ( ny + 1 ) * dy + agents(n)%y
2110	agents(n)%origin_y = ( ny + 1 ) * dy + &
2111	agents(n)%origin_y
2112
2113	ELSEIF ( ibc_mas_ns == 1 ) THEN
2114	!
2115	!-- Agent absorption
2116	agents(n)%agent_mask = .FALSE.
2117	deleted_agents = deleted_agents + 1
2118	ENDIF
2119
2120	ELSEIF ( agents(n)%y >= ( ny + 0.5_wp ) * dy ) THEN
2121
2122	IF ( ibc_mas_ns == 0 ) THEN
2123	!
2124	!-- Cyclic boundary. Relevant coordinate has to be changed.
2125	agents(n)%y = agents(n)%y - ( ny + 1 ) * dy
2126
2127	ELSEIF ( ibc_mas_ns == 1 ) THEN
2128	!
2129	!-- Agent absorption
2130	agents(n)%agent_mask = .FALSE.
2131	deleted_agents = deleted_agents + 1
2132	ENDIF
2133
2134	ENDIF
2135
2136	ENDDO
2137	ENDDO
2138	ENDDO
2139	#endif
2140
2141	!
2142	!-- Accumulate the number of agents transferred between the subdomains
2143	#if defined( __parallel )
2144	CALL mas_eh_ghost_exchange
2145	#endif
2146
2147	CALL cpu_log( log_point_s(18), 'mas_eh_exchange_horiz', 'stop' )
2148
2149	END SUBROUTINE mas_eh_exchange_horiz
2150
2151	!------------------------------------------------------------------------------!
2152	! Description:
2153	! ------------
2154	!> Sends the agents from the three gridcells closest to the
2155	!> north/south/left/right border of a PE to the corresponding neighbors ghost
2156	!> layer (which is three grid boxes deep)
2157	!------------------------------------------------------------------------------!
2158	SUBROUTINE mas_eh_ghost_exchange
2159
2160	IMPLICIT NONE
2161
2162	INTEGER(iwp) :: i !< grid index (x) of agent positition
2163	INTEGER(iwp) :: ip !< index variable along x
2164	INTEGER(iwp) :: j !< grid index (y) of agent positition
2165	INTEGER(iwp) :: jp !< index variable along y
2166	INTEGER(iwp) :: agt_size !< Bit size of agent datatype
2167	INTEGER(iwp) :: ghla_count !< ghost points left agent
2168	INTEGER(iwp) :: ghna_count !< ghost points north agent
2169	INTEGER(iwp) :: ghra_count !< ghost points right agent
2170	INTEGER(iwp) :: ghsa_count !< ghost points south agent
2171
2172	LOGICAL :: ghla_empty !< ghost points left agent
2173	LOGICAL :: ghla_empty_rcv !< ghost points left agent
2174	LOGICAL :: ghna_empty !< ghost points north agent
2175	LOGICAL :: ghna_empty_rcv !< ghost points north agent
2176	LOGICAL :: ghra_empty !< ghost points right agent
2177	LOGICAL :: ghra_empty_rcv !< ghost points right agent
2178	LOGICAL :: ghsa_empty !< ghost points south agent
2179	LOGICAL :: ghsa_empty_rcv !< ghost points south agent
2180
2181	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: ghla !< agents received from right PE
2182	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: ghna !< agents received from south PE
2183	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: ghra !< agents received from left PE
2184	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: ghsa !< agents received from north PE
2185
2186	ghla_empty = .TRUE.
2187	ghna_empty = .TRUE.
2188	ghra_empty = .TRUE.
2189	ghsa_empty = .TRUE.
2190	!
2191	!-- reset ghost layer
2192	DO ip = nxlg, nxl-1
2193	DO jp = nysg, nyng
2194	agt_count(jp,ip) = 0
2195	ENDDO
2196	ENDDO
2197	DO ip = nxr+1, nxrg
2198	DO jp = nysg, nyng
2199	agt_count(jp,ip) = 0
2200	ENDDO
2201	ENDDO
2202	DO ip = nxl, nxr
2203	DO jp = nysg, nys-1
2204	agt_count(jp,ip) = 0
2205	ENDDO
2206	ENDDO
2207	DO ip = nxl, nxr
2208	DO jp = nyn+1, nyng
2209	agt_count(jp,ip) = 0
2210	ENDDO
2211	ENDDO
2212	!
2213	!-- Transfer of agents from left to right and vice versa
2214	IF ( pdims(1) /= 1 ) THEN
2215	!
2216	!-- Reset left and right ghost layers
2217	ghla_count = 0
2218	ghra_count = 0
2219	!
2220	!-- First calculate the storage necessary for sending
2221	!-- and receiving the data.
2222	ghla_count = SUM(agt_count(nys:nyn,nxl:nxl+2))
2223	ghra_count = SUM(agt_count(nys:nyn,nxr-2:nxr))
2224	!
2225	!-- No cyclic boundaries for agents
2226	IF ( nxl == 0 .OR. ghla_count == 0 ) THEN
2227	ghla_count = 1
2228	ELSE
2229	ghla_empty = .FALSE.
2230	ENDIF
2231	IF ( nxr == nx .OR. ghra_count == 0 ) THEN
2232	ghra_count = 1
2233	ELSE
2234	ghra_empty = .FALSE.
2235	ENDIF
2236	ALLOCATE( ghla(1:ghla_count), ghra(1:ghra_count) )
2237	ghla = zero_agent
2238	ghra = zero_agent
2239	!
2240	!-- Get all agents that will be sent left into one array
2241	ghla_count = 0
2242	IF ( nxl /= 0 ) THEN
2243	DO ip = nxl, nxl+2
2244	DO jp = nys, nyn
2245
2246	number_of_agents = agt_count(jp,ip)
2247	IF ( number_of_agents <= 0 ) CYCLE
2248	ghla(ghla_count+1:ghla_count+number_of_agents) &
2249	= grid_agents(jp,ip)%agents(1:number_of_agents)
2250	ghla_count = ghla_count + number_of_agents
2251
2252	ENDDO
2253	ENDDO
2254	ENDIF
2255	IF ( ghla_count == 0 ) ghla_count = 1
2256	!
2257	!-- Get all agents that will be sent right into one array
2258	ghra_count = 0
2259	IF ( nxr /= nx ) THEN
2260	DO ip = nxr-2, nxr
2261	DO jp = nys, nyn
2262
2263	number_of_agents = agt_count(jp,ip)
2264	IF ( number_of_agents <= 0 ) CYCLE
2265	ghra(ghra_count+1:ghra_count+number_of_agents) &
2266	= grid_agents(jp,ip)%agents(1:number_of_agents)
2267	ghra_count = ghra_count + number_of_agents
2268
2269	ENDDO
2270	ENDDO
2271	ENDIF
2272	IF ( ghra_count == 0 ) ghra_count = 1
2273	!
2274	!-- Send/receive number of agents that
2275	!-- will be transferred to/from left/right neighbor
2276	CALL MPI_SENDRECV( ghla_count, 1, MPI_INTEGER, pleft, 0, &
2277	ghra_count_recv, 1, MPI_INTEGER, pright, 0, &
2278	comm2d, status, ierr )
2279	ALLOCATE ( agt_gh_r(1:ghra_count_recv) )
2280	!
2281	!-- Send/receive number of agents that
2282	!-- will be transferred to/from right/left neighbor
2283	CALL MPI_SENDRECV( ghra_count, 1, MPI_INTEGER, pright, 0, &
2284	ghla_count_recv, 1, MPI_INTEGER, pleft, 0, &
2285	comm2d, status, ierr )
2286	!
2287	!-- Send/receive flag that indicates if there are actually any agents
2288	!-- in ghost layer
2289	CALL MPI_SENDRECV( ghla_empty, 1, MPI_LOGICAL, pleft, 1, &
2290	ghra_empty_rcv, 1, MPI_LOGICAL, pright,1, &
2291	comm2d, status, ierr )
2292	CALL MPI_SENDRECV( ghra_empty, 1, MPI_LOGICAL, pright,1, &
2293	ghla_empty_rcv, 1, MPI_LOGICAL, pleft, 1, &
2294	comm2d, status, ierr )
2295
2296
2297	ALLOCATE ( agt_gh_l(1:ghla_count_recv) )
2298	!
2299	!-- Get bit size of one agent
2300	agt_size = C_SIZEOF(zero_agent)
2301	!
2302	!-- Send/receive agents to/from left/right neighbor
2303	CALL MPI_SENDRECV( ghla, ghla_count * agt_size, MPI_BYTE, &
2304	pleft, 1, &
2305	agt_gh_r, ghra_count_recv * agt_size, MPI_BYTE, &
2306	pright,1, &
2307	comm2d, status, ierr )
2308	!
2309	!-- Send/receive agents to/from left/right neighbor
2310	CALL MPI_SENDRECV( ghra, ghra_count * agt_size, MPI_BYTE, &
2311	pright,1, &
2312	agt_gh_l, ghla_count_recv * agt_size, MPI_BYTE, &
2313	pleft, 1, &
2314	comm2d, status, ierr )
2315	!
2316	!-- If agents were received, add them to the respective ghost layer cells
2317	IF ( .NOT. ghra_empty_rcv ) THEN
2318	CALL mas_eh_add_ghost_agents_to_gridcell(agt_gh_r)
2319	ENDIF
2320
2321	IF ( .NOT. ghla_empty_rcv ) THEN
2322	CALL mas_eh_add_ghost_agents_to_gridcell(agt_gh_l)
2323	ENDIF
2324
2325	DEALLOCATE( ghla, ghra, agt_gh_l, agt_gh_r )
2326
2327	ENDIF
2328
2329	!
2330	!-- Transfer of agents from south to north and vice versa
2331	IF ( pdims(2) /= 1 ) THEN
2332	!
2333	!-- Reset south and north ghost layers
2334	ghsa_count = 0
2335	ghna_count = 0
2336	!
2337	!-- First calculate the storage necessary for sending
2338	!-- and receiving the data.
2339	ghsa_count = SUM(agt_count(nys:nys+2,nxlg:nxrg))
2340	ghna_count = SUM(agt_count(nyn-2:nyn,nxlg:nxrg))
2341	!
2342	!-- No cyclic boundaries for agents
2343	IF ( nys == 0 .OR. ghsa_count == 0 ) THEN
2344	ghsa_count = 1
2345	ELSE
2346	ghsa_empty = .FALSE.
2347	ENDIF
2348	IF ( nyn == ny .OR. ghna_count == 0 ) THEN
2349	ghna_count = 1
2350	ELSE
2351	ghna_empty = .FALSE.
2352	ENDIF
2353	ALLOCATE( ghsa(1:ghsa_count), ghna(1:ghna_count) )
2354	ghsa = zero_agent
2355	ghna = zero_agent
2356	!
2357	!-- Get all agents that will be sent south into one array
2358	ghsa_count = 0
2359	IF ( nys /= 0 ) THEN
2360	DO ip = nxlg, nxrg
2361	DO jp = nys, nys+2
2362
2363	number_of_agents = agt_count(jp,ip)
2364	IF ( number_of_agents <= 0 ) CYCLE
2365	ghsa(ghsa_count+1:ghsa_count+number_of_agents) &
2366	= grid_agents(jp,ip)%agents(1:number_of_agents)
2367	ghsa_count = ghsa_count + number_of_agents
2368
2369	ENDDO
2370	ENDDO
2371	ENDIF
2372	IF ( ghsa_count == 0 ) ghsa_count = 1
2373	!
2374	!-- Get all agents that will be sent north into one array
2375	ghna_count = 0
2376	IF ( nyn /= ny ) THEN
2377	DO ip = nxlg, nxrg
2378	DO jp = nyn-2, nyn
2379
2380	number_of_agents = agt_count(jp,ip)
2381	IF ( number_of_agents <= 0 ) CYCLE
2382	ghna(ghna_count+1:ghna_count+number_of_agents) &
2383	= grid_agents(jp,ip)%agents(1:number_of_agents)
2384	ghna_count = ghna_count + number_of_agents
2385
2386	ENDDO
2387	ENDDO
2388	ENDIF
2389	IF ( ghna_count == 0 ) ghna_count = 1
2390	!
2391	!-- Send/receive number of agents that
2392	!-- will be transferred to/from south/north neighbor
2393	CALL MPI_SENDRECV( ghsa_count, 1, MPI_INTEGER, psouth, 0, &
2394	ghna_count_recv, 1, MPI_INTEGER, pnorth, 0, &
2395	comm2d, status, ierr )
2396	ALLOCATE ( agt_gh_n(1:ghna_count_recv) )
2397	!
2398	!-- Send/receive number of agents that
2399	!-- will be transferred to/from north/south neighbor
2400	CALL MPI_SENDRECV( ghna_count, 1, MPI_INTEGER, pnorth, 0, &
2401	ghsa_count_recv, 1, MPI_INTEGER, psouth, 0, &
2402	comm2d, status, ierr )
2403	!
2404	!-- Send/receive flag that indicates if there are actually any agents
2405	!-- in ghost layer
2406	CALL MPI_SENDRECV( ghsa_empty, 1, MPI_LOGICAL, psouth, 1, &
2407	ghna_empty_rcv, 1, MPI_LOGICAL, pnorth, 1, &
2408	comm2d, status, ierr )
2409	CALL MPI_SENDRECV( ghna_empty, 1, MPI_LOGICAL, pnorth, 1, &
2410	ghsa_empty_rcv, 1, MPI_LOGICAL, psouth, 1, &
2411	comm2d, status, ierr )
2412
2413
2414	ALLOCATE ( agt_gh_s(1:ghsa_count_recv) )
2415	!
2416	!-- Get bit size of one agent
2417	agt_size = C_SIZEOF(zero_agent)
2418	!
2419	!-- Send/receive agents to/from south/north neighbor
2420	CALL MPI_SENDRECV( ghsa, ghsa_count * agt_size, MPI_BYTE, &
2421	psouth,1, &
2422	agt_gh_n, ghna_count_recv * agt_size, MPI_BYTE, &
2423	pnorth,1, &
2424	comm2d, status, ierr )
2425	!
2426	!-- Send/receive agents to/from south/north neighbor
2427	CALL MPI_SENDRECV( ghna, ghna_count * agt_size, MPI_BYTE, &
2428	pnorth,1, &
2429	agt_gh_s, ghsa_count_recv * agt_size, MPI_BYTE, &
2430	psouth,1, &
2431	comm2d, status, ierr )
2432	!
2433	!-- If agents were received, add them to the respective ghost layer cells
2434	IF ( .NOT. ghna_empty_rcv ) THEN
2435	CALL mas_eh_add_ghost_agents_to_gridcell(agt_gh_n)
2436	ENDIF
2437
2438	IF ( .NOT. ghsa_empty_rcv ) THEN
2439	CALL mas_eh_add_ghost_agents_to_gridcell(agt_gh_s)
2440	ENDIF
2441
2442	DEALLOCATE( ghna, ghsa, agt_gh_n, agt_gh_s )
2443
2444	ENDIF
2445
2446	END SUBROUTINE mas_eh_ghost_exchange
2447
2448	!------------------------------------------------------------------------------!
2449	! Description:
2450	! ------------
2451	!> If an agent moves from one grid cell to another (on the current
2452	!> processor!), this subroutine moves the corresponding element from the
2453	!> agent array of the old grid cell to the agent array of the new grid
2454	!> cell.
2455	!------------------------------------------------------------------------------!
2456	SUBROUTINE mas_eh_move_agent
2457
2458	IMPLICIT NONE
2459
2460	INTEGER(iwp) :: i !< grid index (x) of agent position
2461	INTEGER(iwp) :: ip !< index variable along x
2462	INTEGER(iwp) :: j !< grid index (y) of agent position
2463	INTEGER(iwp) :: jp !< index variable along y
2464	INTEGER(iwp) :: n !< index variable for agent array
2465	INTEGER(iwp) :: na_before_move !< number of agents per grid box before moving
2466	INTEGER(iwp) :: aindex !< dummy argument for number of new agent per grid box
2467
2468	TYPE(agent_type), DIMENSION(:), POINTER :: agents_before_move !< agents before moving
2469
2470	CALL cpu_log( log_point_s(19), 'mas_eh_move_agent', 'start' )
2471
2472	DO ip = nxl, nxr
2473	DO jp = nys, nyn
2474
2475	na_before_move = agt_count(jp,ip)
2476	IF ( na_before_move <= 0 ) CYCLE
2477	agents_before_move => grid_agents(jp,ip)%agents(1:na_before_move)
2478
2479	DO n = 1, na_before_move
2480	i = agents_before_move(n)%x * ddx
2481	j = agents_before_move(n)%y * ddy
2482
2483	!-- For mas_eh_exchange_horiz to work properly agents need to be
2484	!-- moved to the outermost gridboxes of the respective processor.
2485	!-- If the agent index is inside the processor the following
2486	!-- lines will not change the index
2487	i = MIN ( i , nxr )
2488	i = MAX ( i , nxl )
2489	j = MIN ( j , nyn )
2490	j = MAX ( j , nys )
2491
2492	!
2493	!-- Check if agent has moved to another grid cell.
2494	IF ( i /= ip .OR. j /= jp ) THEN
2495	!
2496	!-- If the agent stays on the same processor, the agent
2497	!-- will be added to the agent array of the new processor.
2498	number_of_agents = agt_count(j,i)
2499	agents => grid_agents(j,i)%agents(1:number_of_agents)
2500
2501	aindex = number_of_agents+1
2502	IF ( aindex > SIZE(grid_agents(j,i)%agents) ) &
2503	THEN
2504	CALL mas_eh_realloc_agents_array(i,j)
2505	ENDIF
2506
2507	grid_agents(j,i)%agents(aindex) = agents_before_move(n)
2508	agt_count(j,i) = aindex
2509
2510	agents_before_move(n)%agent_mask = .FALSE.
2511	ENDIF
2512	ENDDO
2513
2514	ENDDO
2515	ENDDO
2516
2517	CALL cpu_log( log_point_s(19), 'mas_eh_move_agent', 'stop' )
2518
2519	RETURN
2520
2521	END SUBROUTINE mas_eh_move_agent
2522
2523	!------------------------------------------------------------------------------!
2524	! Description:
2525	! ------------
2526	!> If the allocated memory for the agent array do not suffice to add arriving
2527	!> agents from neighbour grid cells, this subrouting reallocates the
2528	!> agent array to assure enough memory is available.
2529	!------------------------------------------------------------------------------!
2530	SUBROUTINE mas_eh_realloc_agents_array (i,j,size_in)
2531
2532	IMPLICIT NONE
2533
2534	INTEGER(iwp) :: old_size !< old array size
2535	INTEGER(iwp) :: new_size !< new array size
2536
2537	INTEGER(iwp), INTENT(in) :: i !< grid index (y)
2538	INTEGER(iwp), INTENT(in) :: j !< grid index (y)
2539
2540	INTEGER(iwp), INTENT(in), OPTIONAL :: size_in !< size of input array
2541
2542	TYPE(agent_type), DIMENSION(10) :: tmp_agents_s !< temporary static agent array
2543
2544	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: tmp_agents_d !< temporary dynamic agent array
2545
2546	old_size = SIZE(grid_agents(j,i)%agents)
2547
2548	IF ( PRESENT(size_in) ) THEN
2549	new_size = size_in
2550	ELSE
2551	new_size = old_size * ( 1.0_wp + alloc_factor_mas / 100.0_wp )
2552	ENDIF
2553
2554	new_size = MAX( new_size, min_nr_agent, old_size + 1 )
2555
2556	IF ( old_size <= 10 ) THEN
2557
2558	tmp_agents_s(1:old_size) = grid_agents(j,i)%agents(1:old_size)
2559
2560	DEALLOCATE(grid_agents(j,i)%agents)
2561	ALLOCATE(grid_agents(j,i)%agents(new_size))
2562
2563	grid_agents(j,i)%agents(1:old_size) = tmp_agents_s(1:old_size)
2564	grid_agents(j,i)%agents(old_size+1:new_size) = zero_agent
2565
2566	ELSE
2567
2568	ALLOCATE(tmp_agents_d(new_size))
2569	tmp_agents_d(1:old_size) = grid_agents(j,i)%agents
2570
2571	DEALLOCATE(grid_agents(j,i)%agents)
2572	ALLOCATE(grid_agents(j,i)%agents(new_size))
2573
2574	grid_agents(j,i)%agents(1:old_size) = tmp_agents_d(1:old_size)
2575	grid_agents(j,i)%agents(old_size+1:new_size) = zero_agent
2576
2577	DEALLOCATE(tmp_agents_d)
2578
2579	ENDIF
2580	agents => grid_agents(j,i)%agents(1:number_of_agents)
2581
2582	RETURN
2583	END SUBROUTINE mas_eh_realloc_agents_array
2584
2585	!------------------------------------------------------------------------------!
2586	! Description:
2587	! ------------
2588	!> Inquires prognostic model quantities at the position of each agent and
2589	!> stores them in that agent for later output
2590	!------------------------------------------------------------------------------!
2591	SUBROUTINE mas_get_prognostic_quantities
2592
2593	USE arrays_3d, &
2594	ONLY: u, v, pt, hyp
2595
2596	USE chem_gasphase_mod, &
2597	ONLY: nvar
2598
2599	USE chemistry_model_mod, &
2600	ONLY: chem_species
2601
2602	USE control_parameters, &
2603	ONLY: air_chemistry
2604
2605	IMPLICIT NONE
2606
2607	INTEGER(iwp) :: i_offset !< index offset for windspeed measurement
2608	INTEGER(iwp) :: il !< x-index
2609	INTEGER(iwp) :: is !< subgrid box counter
2610	INTEGER(iwp) :: j_offset !< index offset for windspeed measurement
2611	INTEGER(iwp) :: jl !< y-index
2612	INTEGER(iwp) :: kl !< z-index
2613	INTEGER(iwp) :: nl !< agent counter
2614	INTEGER(iwp) :: se !< subgrid box end index
2615	INTEGER(iwp) :: si !< subgrid box start index
2616
2617	REAL(wp) :: u_a !< windspeed at agent position (x)
2618	REAL(wp) :: v_a !< windspeed at agent position (y)
2619	REAL(wp) :: x_a !< agent position (x)
2620	REAL(wp) :: y_a !< agent position (y)
2621
2622	DO il = nxl, nxr
2623	DO jl = nys, nyn
2624
2625	number_of_agents = agt_count(jl,il)
2626	!
2627	!-- If grid cell is empty, cycle
2628	IF ( number_of_agents <= 0 ) CYCLE
2629	kl = s_measure_height(jl,il)
2630
2631	agents => grid_agents(jl,il)%agents(1:number_of_agents)
2632	!
2633	!-- loop over the four subgrid boxes
2634	DO is = 0,3
2635	!
2636	!-- Set indices
2637	si = grid_agents(jl,il)%start_index(is)
2638	se = grid_agents(jl,il)%end_index(is)
2639	DO nl = si, se
2640	!
2641	!-- Calculate index offset in x-direction:
2642	!-- Left value if wall right of grid box
2643	!-- Right value if wall left of grid box
2644	!-- Else the one that is closer to the agent
2645	IF ( BTEST( obstacle_flags( jl, il+1 ), 6 ) ) THEN
2646	i_offset = 0
2647	ELSEIF ( BTEST( obstacle_flags( jl, il-1 ), 2 ) ) THEN
2648	i_offset = 1
2649	ELSE
2650	i_offset = MERGE( 0, 1, BTEST(is,1) )
2651	ENDIF
2652	u_a = u( kl, jl, il + i_offset )
2653	!
2654	!-- Calculate index offset in y-direction:
2655	!-- South value if wall north of grid box
2656	!-- North value if wall south of grid box
2657	!-- Else the one that is closer to the agent
2658	IF ( BTEST( obstacle_flags( jl+1, il ), 4 ) ) THEN
2659	j_offset = 0
2660	ELSEIF ( BTEST( obstacle_flags( jl-1, il ), 0 ) ) THEN
2661	j_offset = 1
2662	ELSE
2663	j_offset = MERGE( 0, 1, BTEST(is,0) )
2664	ENDIF
2665	v_a = v( kl, jl + j_offset, il )
2666	!
2667	!-- Calculate windspeed at agent postion
2668	agents(nl)%windspeed = SQRT(u_a2 + v_a2)
2669	!
2670	!-- Calculate temperature at agent position
2671	agents(nl)%t = pt(kl,jl,il) * &
2672	( hyp(kl) / 100000.0_wp )**0.286_wp
2673	! !
2674	! !-- Get PM10 concentration at agent position, if possible
2675	! IF ( ind_pm10 == -9 ) THEN
2676	! agents(nl)%pm10 = 0.0_wp
2677	! ELSE
2678	! agents(nl)%pm10 = chem_species(ind_pm10)%conc(kl,jl,il)
2679	! ENDIF
2680	! !
2681	! !-- Get PM10 concentration at agent position, if possible
2682	! IF ( ind_pm25 == -9 ) THEN
2683	! agents(nl)%pm25 = 0.0_wp
2684	! ELSE
2685	! agents(nl)%pm25 = chem_species(ind_pm25)%conc(kl,jl,il)
2686	! ENDIF
2687	ENDDO
2688
2689	ENDDO
2690
2691	ENDDO
2692	ENDDO
2693
2694	END SUBROUTINE mas_get_prognostic_quantities
2695
2696	!------------------------------------------------------------------------------!
2697	! Description:
2698	! ------------
2699	!> Adds an item to the priority queue (binary heap) at the correct position
2700	!------------------------------------------------------------------------------!
2701	SUBROUTINE mas_heap_insert_item( id, priority )
2702
2703	IMPLICIT NONE
2704
2705	INTEGER(iwp) :: cur_pos !< current position
2706	INTEGER(iwp) :: id !< mesh ID of item
2707
2708	REAL(wp) :: priority !< item priority
2709
2710	TYPE(heap_item) :: item !< heap item
2711
2712	item%mesh_id = id
2713	item%priority = priority
2714	!
2715	!-- Extend heap, if necessary
2716	IF ( heap_count + 1 > SIZE(queue) ) THEN
2717	CALL mas_heap_extend
2718	ENDIF
2719	!
2720	!-- Insert item at first unoccupied postion (highest index) of heap
2721	cur_pos = heap_count
2722	queue(cur_pos) = item
2723	!
2724	!-- Sort while inserted item is not at top of heap
2725	DO WHILE ( cur_pos /= 0 )
2726	!
2727	!-- If priority < its parent's priority, swap them.
2728	!-- Else, sorting is done.
2729	IF ( queue(cur_pos)%priority &
2730	< queue(FLOOR((cur_pos)/2.))%priority ) &
2731	THEN
2732	item = queue(cur_pos)
2733	queue(cur_pos) = queue(FLOOR((cur_pos)/2.))
2734	queue(FLOOR((cur_pos)/2.)) = item
2735	cur_pos = FLOOR((cur_pos)/2.)
2736	ELSE
2737	EXIT
2738	ENDIF
2739	ENDDO
2740	!
2741	!-- Item was added to heap, so the heap count increases
2742	heap_count = heap_count + 1
2743
2744	END SUBROUTINE mas_heap_insert_item
2745
2746	!------------------------------------------------------------------------------!
2747	! Description:
2748	! ------------
2749	!> Extends the size of the priority queue (binary heap)
2750	!------------------------------------------------------------------------------!
2751	SUBROUTINE mas_heap_extend
2752
2753	IMPLICIT NONE
2754
2755	INTEGER(iwp) :: soh !< size of heap
2756
2757	TYPE(heap_item), DIMENSION(:), ALLOCATABLE :: dummy_heap !< dummy heap
2758
2759	soh = SIZE(queue)-1
2760	ALLOCATE(dummy_heap(0:soh))
2761	dummy_heap = queue
2762	DEALLOCATE(queue)
2763	ALLOCATE(queue(0:2*soh+1))
2764	queue(0:soh) = dummy_heap(0:soh)
2765
2766	END SUBROUTINE mas_heap_extend
2767
2768	!------------------------------------------------------------------------------!
2769	! Description:
2770	! ------------
2771	!> Removes first (smallest) element from the priority queue, reorders the rest
2772	!> and returns the ID of the removed mesh point
2773	!------------------------------------------------------------------------------!
2774	SUBROUTINE mas_heap_extract_item ( id )
2775
2776	IMPLICIT NONE
2777
2778	INTEGER(iwp) :: id !< ID of item extracted item
2779	INTEGER(iwp) :: child !< child of item in heap
2780	INTEGER(iwp) :: cur_pos !< current position of item in heap
2781
2782	TYPE(heap_item) :: dummy
2783	!
2784	!-- Get ID of mesh point with lowest priority (extracted item: top of heap)
2785	id = queue(0)%mesh_id
2786	!
2787	!-- Put last item in heap at first position
2788	queue(0) = queue(heap_count-1)
2789	cur_pos = 0
2790	DO
2791	!
2792	!-- If current item has no children, sorting is done
2793	IF( 2*cur_pos+1 > heap_count - 1 ) THEN
2794	EXIT
2795	!
2796	!-- If current item has only one child, check if item and its child are
2797	!-- ordered correctly. Else, swap them.
2798	ELSEIF ( 2*cur_pos+2 > heap_count - 1 ) THEN
2799	IF ( queue(cur_pos)%priority > queue(2*cur_pos+1)%priority ) THEN
2800	dummy = queue(cur_pos)
2801	queue(cur_pos) = queue(2*cur_pos+1)
2802	queue(2*cur_pos+1) = dummy
2803	cur_pos = 2*cur_pos+1
2804	ELSE
2805	EXIT
2806	ENDIF
2807	ELSE
2808	!
2809	!-- determine the smaller child
2810	IF ( queue(2*cur_pos+1)%priority &
2811	>= queue(2*cur_pos+2)%priority ) &
2812	THEN
2813	child = 2
2814	ELSE
2815	child = 1
2816	ENDIF
2817	!
2818	!-- Check if item and its smaller child are ordered falsely. If so,
2819	!-- swap them. Else, sorting is done.
2820	IF ( queue(cur_pos)%priority > queue(2*cur_pos+child )%priority ) &
2821	THEN
2822	dummy = queue(cur_pos)
2823	queue(cur_pos) = queue(2*cur_pos+child)
2824	queue(2*cur_pos+child) = dummy
2825	cur_pos = 2*cur_pos+child
2826	ELSE
2827	EXIT
2828	ENDIF
2829	ENDIF
2830	ENDDO
2831	!
2832	!-- Top item was removed from heap, thus, heap_cout decreases by one
2833	heap_count = heap_count-1
2834
2835	END SUBROUTINE mas_heap_extract_item
2836
2837	!------------------------------------------------------------------------------!
2838	! Description:
2839	! ------------
2840	!> Initialization of Multi Agent System
2841	!------------------------------------------------------------------------------!
2842	SUBROUTINE mas_init
2843
2844	USE chem_gasphase_mod, &
2845	ONLY: nspec
2846
2847	USE chemistry_model_mod, &
2848	ONLY: chem_species
2849
2850	USE control_parameters, &
2851	ONLY: air_chemistry, coupling_char, initializing_actions, &
2852	io_blocks, io_group
2853
2854	USE surface_mod, &
2855	ONLY: get_topography_top_index, get_topography_top_index_ji
2856
2857	USE arrays_3d, &
2858	ONLY: zu, zw
2859
2860	USE indices, &
2861	ONLY: nzt
2862
2863	IMPLICIT NONE
2864
2865	INTEGER(iwp) :: i !< grid cell (x)
2866	INTEGER(iwp) :: ii !< io-block counter
2867	INTEGER(iwp) :: il !< io-block counter
2868	INTEGER(iwp) :: jl !< io-block counter
2869	INTEGER(iwp) :: kl !< io-block counter
2870	INTEGER(iwp) :: kdum !< io-block counter
2871	INTEGER(iwp) :: locdum !< io-block counter
2872	INTEGER(iwp) :: j !< grid cell (y)
2873	INTEGER(iwp) :: size_of_mesh !< temporary value for read
2874	INTEGER(iwp) :: size_of_pols !< temporary value for read
2875	INTEGER(iwp) :: ioerr !< IOSTAT flag for IO-commands ( 0 = no error )
2876
2877	REAL(wp) :: zdum !< dummy for measurement height
2878	REAL(wp) :: avg_agt_height = 1.8_wp
2879
2880	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: noc !< temp: number of connections in nav_mesh
2881
2882	!
2883	!-- Check the number of agent groups.
2884	IF ( number_of_agent_groups > max_number_of_agent_groups ) THEN
2885	WRITE( message_string, * ) 'max_number_of_agent_groups =', &
2886	max_number_of_agent_groups , &
2887	'&number_of_agent_groups reset to ', &
2888	max_number_of_agent_groups
2889	CALL message( 'mas_init', 'PA0072', 0, 1, 0, 6, 0 )
2890	number_of_agent_groups = max_number_of_agent_groups
2891	ENDIF
2892
2893	!
2894	!-- Set some parameters
2895	d_sigma_rep_agent = 1.0_wp/sigma_rep_agent
2896	d_sigma_rep_wall = 1.0_wp/sigma_rep_wall
2897	d_tau_accel_agent = 1.0_wp/tau_accel_agent
2898	IF ( dt_agent /= 999.0_wp ) THEN
2899	agent_own_timestep = .TRUE.
2900	ENDIF
2901
2902	!
2903	!-- Get index of first grid box above topography
2904	ALLOCATE( top_top_s(nysg:nyng,nxlg:nxrg), &
2905	top_top_w(nysg:nyng,nxlg:nxrg), &
2906	s_measure_height(nys:nyn,nxl:nxr) )
2907	!
2908	!-- Get first index above topography for scalar grid and last index in
2909	!-- topography for z-component of wind
2910	DO il = nxlg, nxrg
2911	DO jl = nysg, nyng
2912	top_top_s(jl,il) = get_topography_top_index_ji(jl,il,'s') + 1
2913	top_top_w(jl,il) = get_topography_top_index_ji(jl,il,'w')
2914	ENDDO
2915	ENDDO
2916	!
2917	!-- Create 2D array containing the index at which measurements are done by
2918	!-- agents. The height of this measurement is given by avg_agt_height.
2919	DO il = nxl, nxr
2920	DO jl = nys, nyn
2921
2922	kdum = top_top_w(jl,il)
2923	zdum = zw(kdum)
2924	zdum = zdum + avg_agt_height
2925	locdum = 0
2926	!
2927	!-- Locate minimum distance from u-grid to measurement height (zdum)
2928	DO kl = 1, nzt
2929	IF ( ABS(zu(kl)-zdum) < ABS(zu(locdum)-zdum) ) locdum = kl
2930	ENDDO
2931	s_measure_height(jl,il) = locdum
2932
2933	ENDDO
2934	ENDDO
2935	! !
2936	! !-- Get indices of PM10 and PM2.5 species, if active
2937	! IF ( air_chemistry ) THEN
2938	! DO il = 1, nspec
2939	! print*,chem_species(il)%name
2940	! ! IF ( spec_name(1:4) == 'PM10' ) THEN
2941	! ! ind_pm10 = il
2942	! ! ELSEIF ( spec_name(1:4) == 'PM25' ) THEN
2943	! ! ind_pm25 = il
2944	! ! ENDIF
2945	!
2946	! ENDDO
2947	! ENDIF
2948	! stop
2949	CALL mas_create_obstacle_flags
2950
2951	!
2952	!-- Set default start positions, if necessary
2953	IF ( asl(1) == 9999999.9_wp ) asl(1) = 0.0_wp
2954	IF ( asr(1) == 9999999.9_wp ) asr(1) = ( nx + 1 ) * dx
2955	IF ( ass(1) == 9999999.9_wp ) ass(1) = 0.0_wp
2956	IF ( asn(1) == 9999999.9_wp ) asn(1) = ( ny + 1 ) * dy
2957	IF ( adx(1) == 9999999.9_wp .OR. adx(1) == 0.0_wp ) adx(1) = dx
2958	IF ( ady(1) == 9999999.9_wp .OR. ady(1) == 0.0_wp ) ady(1) = dy
2959
2960	DO j = 2, number_of_agent_groups
2961	IF ( asl(j) == 9999999.9_wp ) asl(j) = asl(j-1)
2962	IF ( asr(j) == 9999999.9_wp ) asr(j) = asr(j-1)
2963	IF ( ass(j) == 9999999.9_wp ) ass(j) = ass(j-1)
2964	IF ( asn(j) == 9999999.9_wp ) asn(j) = asn(j-1)
2965	IF ( adx(j) == 9999999.9_wp .OR. adx(j) == 0.0_wp ) adx(j) = adx(j-1)
2966	IF ( ady(j) == 9999999.9_wp .OR. ady(j) == 0.0_wp ) ady(j) = ady(j-1)
2967	ENDDO
2968
2969	!
2970	!-- Check boundary condition and set internal variables
2971	SELECT CASE ( bc_mas_lr )
2972
2973	CASE ( 'cyclic' )
2974	ibc_mas_lr = 0
2975
2976	CASE ( 'absorb' )
2977	ibc_mas_lr = 1
2978
2979	CASE DEFAULT
2980	WRITE( message_string, * ) 'unknown boundary condition ', &
2981	'bc_mas_lr = "', TRIM( bc_mas_lr ), '"'
2982	CALL message( 'mas_init', 'PA0073', 1, 2, 0, 6, 0 )
2983
2984	END SELECT
2985	SELECT CASE ( bc_mas_ns )
2986
2987	CASE ( 'cyclic' )
2988	ibc_mas_ns = 0
2989
2990	CASE ( 'absorb' )
2991	ibc_mas_ns = 1
2992
2993	CASE DEFAULT
2994	WRITE( message_string, * ) 'unknown boundary condition ', &
2995	'bc_mas_ns = "', TRIM( bc_mas_ns ), '"'
2996	CALL message( 'mas_init', 'PA0074', 1, 2, 0, 6, 0 )
2997
2998	END SELECT
2999
3000	!
3001	!-- For the first model run of a possible job chain initialize the
3002	!-- agents, otherwise read the agent data from restart file.
3003	IF ( TRIM( initializing_actions ) == 'read_restart_data' &
3004	.AND. read_agents_from_restartfile ) THEN
3005
3006	! CALL mas_read_restart_file
3007
3008	ELSE
3009	!
3010	!-- Read preprocessed data of navigation mesh and building polygons
3011	!-- for agent pathfinding
3012	DO ii = 0, io_blocks-1
3013	IF ( ii == io_group ) THEN
3014	OPEN ( 119, FILE='NAVIGATION_DATA'//TRIM( coupling_char ), &
3015	FORM='UNFORMATTED', IOSTAT=ioerr )
3016	!
3017	!-- Read mesh data
3018	READ(119) size_of_mesh
3019	ALLOCATE( mesh(1:size_of_mesh))
3020	DO i = 1, size_of_mesh
3021	READ(119) mesh(i)%polygon_id, mesh(i)%vertex_id, &
3022	mesh(i)%noc, mesh(i)%origin_id, &
3023	mesh(i)%cost_so_far, mesh(i)%x, &
3024	mesh(i)%y, mesh(i)%x_s, mesh(i)%y_s
3025	ALLOCATE( mesh(i)%connected_vertices(1:mesh(i)%noc), &
3026	mesh(i)%distance_to_vertex(1:mesh(i)%noc) )
3027	DO j = 1, mesh(i)%noc
3028	READ(119) mesh(i)%connected_vertices(j), &
3029	mesh(i)%distance_to_vertex(j)
3030	ENDDO
3031	ENDDO
3032	!
3033	!-- Read polygon data
3034	READ(119) size_of_pols
3035	ALLOCATE( polygons(1:size_of_pols) )
3036	DO i = 1, size_of_pols
3037	READ(119) polygons(i)%nov
3038	ALLOCATE( polygons(i)%vertices(0:polygons(i)%nov+1) )
3039	DO j = 0, polygons(i)%nov+1
3040	READ(119) polygons(i)%vertices(j)%delete, &
3041	polygons(i)%vertices(j)%x, &
3042	polygons(i)%vertices(j)%y
3043	ENDDO
3044	ENDDO
3045	CLOSE(119)
3046
3047	ENDIF
3048	#if defined( __parallel ) && ! defined ( __check )
3049	CALL MPI_BARRIER( comm2d, ierr )
3050	#endif
3051	ENDDO
3052
3053	!
3054	!-- Allocate agent arrays and set attributes of the initial set of
3055	!-- agents, which can be also periodically released at later times.
3056	ALLOCATE( agt_count (nysg:nyng,nxlg:nxrg), &
3057	grid_agents(nysg:nyng,nxlg:nxrg) )
3058
3059	number_of_agents = 0
3060	sort_count_mas = 0
3061	agt_count = 0
3062
3063	!
3064	!-- initialize counter for agent IDs
3065	grid_agents%id_counter = 1
3066
3067	!
3068	!-- Initialize all agents with dummy values (otherwise errors may
3069	!-- occur within restart runs). The reason for this is still not clear
3070	!-- and may be presumably caused by errors in the respective user-interface.
3071	zero_agent%agent_mask = .FALSE.
3072	zero_agent%block_nr = -1
3073	zero_agent%group = 0
3074	zero_agent%id = 0_idp
3075	zero_agent%path_counter = SIZE(zero_agent%path_x)
3076	zero_agent%age = 0.0_wp
3077	zero_agent%age_m = 0.0_wp
3078	zero_agent%dt_sum = 0.0_wp
3079	zero_agent%clo = 0.0_wp
3080	zero_agent%energy_storage= 0.0_wp
3081	zero_agent%force_x = 0.0_wp
3082	zero_agent%force_y = 0.0_wp
3083	zero_agent%origin_x = 0.0_wp
3084	zero_agent%origin_y = 0.0_wp
3085	zero_agent%speed_abs = 0.0_wp
3086	zero_agent%speed_e_x = 0.0_wp
3087	zero_agent%speed_e_y = 0.0_wp
3088	zero_agent%speed_des = random_normal(desired_speed, des_sp_sig)
3089	zero_agent%speed_x = 0.0_wp
3090	zero_agent%speed_y = 0.0_wp
3091	zero_agent%thermal_index = 0.0_wp
3092	zero_agent%x = 0.0_wp
3093	zero_agent%y = 0.0_wp
3094	zero_agent%path_x = 0.0_wp
3095	zero_agent%path_y = 0.0_wp
3096	zero_agent%t_x = 0.0_wp
3097	zero_agent%t_y = 0.0_wp
3098
3099	!
3100	!-- Set a seed value for the random number generator to be exclusively
3101	!-- used for the agent code. The generated random numbers should be
3102	!-- different on the different PEs.
3103	iran_agent = iran_agent + myid
3104
3105	CALL mas_create_agent (PHASE_INIT)
3106
3107	ENDIF
3108
3109	!
3110	!-- To avoid programm abort, assign agents array to the local version of
3111	!-- first grid cell
3112	number_of_agents = agt_count(nys,nxl)
3113	agents => grid_agents(nys,nxl)%agents(1:number_of_agents)
3114
3115	END SUBROUTINE mas_init
3116
3117	!------------------------------------------------------------------------------!
3118	! Description:
3119	! ------------
3120	!> Adds a connection between two points of the navigation mesh
3121	!> (one-way: in_mp1 to in_mp2)
3122	!------------------------------------------------------------------------------!
3123	SUBROUTINE mas_nav_add_connection ( in_mp1, id2, in_mp2 )
3124
3125	IMPLICIT NONE
3126
3127	LOGICAL :: connection_established !< Flag to indicate if connection has already been established
3128
3129	INTEGER(iwp) :: id2 !< ID of in_mp2
3130	INTEGER(iwp) :: il !< local counter
3131	INTEGER(iwp) :: noc1 !< number of connections in in_mp1
3132
3133	INTEGER, DIMENSION(:), ALLOCATABLE :: dum_cv !< dummy array for connected_vertices
3134
3135	REAL(wp) :: dist !< Distance between the two points
3136
3137	REAL(wp), DIMENSION(:), ALLOCATABLE :: dum_dtv
3138
3139	TYPE(mesh_point) :: in_mp1 !< mesh point that gets a new connection
3140	TYPE(mesh_point) :: in_mp2 !< mesh point in_mp1 will be connected to
3141
3142	connection_established = .FALSE.
3143	!
3144	!-- Check if connection has already been established
3145	noc1 = SIZE(in_mp1%connected_vertices)
3146	DO il = 1, in_mp1%noc
3147	IF ( in_mp1%connected_vertices(il) == id2 ) THEN
3148	connection_established = .TRUE.
3149	EXIT
3150	ENDIF
3151	ENDDO
3152
3153	IF ( .NOT. connection_established ) THEN
3154	!
3155	!-- Resize arrays, if necessary
3156	IF ( in_mp1%noc >= noc1 ) THEN
3157	ALLOCATE( dum_cv(1:noc1),dum_dtv(1:noc1) )
3158	dum_cv = in_mp1%connected_vertices
3159	dum_dtv = in_mp1%distance_to_vertex
3160	DEALLOCATE( in_mp1%connected_vertices, in_mp1%distance_to_vertex )
3161	ALLOCATE( in_mp1%connected_vertices(1:2*noc1), &
3162	in_mp1%distance_to_vertex(1:2*noc1) )
3163	in_mp1%connected_vertices = -999
3164	in_mp1%distance_to_vertex = -999.
3165	in_mp1%connected_vertices(1:noc1) = dum_cv
3166	in_mp1%distance_to_vertex(1:noc1) = dum_dtv
3167	ENDIF
3168
3169	!
3170	!-- Add connection
3171	in_mp1%noc = in_mp1%noc+1
3172	dist = SQRT( (in_mp1%x - in_mp2%x)2 + (in_mp1%y - in_mp2%y)2 )
3173	in_mp1%connected_vertices(in_mp1%noc) = id2
3174	in_mp1%distance_to_vertex(in_mp1%noc) = dist
3175	ENDIF
3176
3177	END SUBROUTINE mas_nav_add_connection
3178
3179	!------------------------------------------------------------------------------!
3180	! Description:
3181	! ------------
3182	!> Adds a vertex (curren position of agent or target) to the existing tmp_mesh
3183	!------------------------------------------------------------------------------!
3184	SUBROUTINE mas_nav_add_vertex_to_mesh ( in_mp, in_id )
3185
3186	IMPLICIT NONE
3187
3188	LOGICAL :: intersection_found !< flag
3189
3190	INTEGER(iwp) :: jl !< mesh point counter
3191	INTEGER(iwp) :: pl !< polygon counter
3192	INTEGER(iwp) :: vl !< vertex counter
3193	INTEGER(iwp) :: pid_t !< polygon id of tested mesh point
3194	INTEGER(iwp) :: vid_t !< vertex id of tested mesh point
3195	INTEGER(iwp) :: in_id !< vertex id of tested mesh point
3196
3197	REAL(wp) :: v1x !< x-coordinate of test vertex 1 for intersection test
3198	REAL(wp) :: v1y !< y-coordinate of test vertex 1 for intersection test
3199	REAL(wp) :: v2x !< x-coordinate of test vertex 2 for intersection test
3200	REAL(wp) :: v2y !< y-coordinate of test vertex 2 for intersection test
3201	REAL(wp) :: x !< x-coordinate of current mesh point
3202	REAL(wp) :: x_t !< x-coordinate of tested mesh point
3203	REAL(wp) :: y !< y-coordinate of current mesh point
3204	REAL(wp) :: y_t !< y-coordinate of tested mesh point
3205
3206	TYPE(mesh_point) :: in_mp !< Input mesh point
3207	!
3208	!--
3209	x = in_mp%x
3210	y = in_mp%y
3211	DO jl = 0, SIZE(tmp_mesh)-2
3212	IF ( in_id == jl ) CYCLE
3213	!
3214	!-- Ignore mesh points with 0 connections
3215	IF ( tmp_mesh(jl)%polygon_id /= -1 ) THEN
3216	IF ( tmp_mesh(jl)%noc == 0 ) CYCLE
3217	ENDIF
3218	x_t = tmp_mesh(jl)%x
3219	y_t = tmp_mesh(jl)%y
3220	pid_t = tmp_mesh(jl)%polygon_id
3221	vid_t = tmp_mesh(jl)%vertex_id
3222	!
3223	!-- If the connecting line between the target and a mesh point points
3224	!-- into the mesh point's polygon, no connection will be
3225	!-- established between the two points. This is the case if the
3226	!-- previous (next) vertex of the polygon is right of the connecting
3227	!-- line and the next (previous) vertex of the polygon is left of the
3228	!-- connecting line.
3229	IF ( pid_t > 0 .AND. pid_t <= SIZE(polygons) ) THEN
3230	IF ( (((is_left(x,y,x_t,y_t,polygons(pid_t)%vertices(vid_t-1)%x, &
3231	polygons(pid_t)%vertices(vid_t-1)%y) &
3232	.AND. is_right(x,y,x_t,y_t, &
3233	polygons(pid_t)%vertices(vid_t+1)%x, &
3234	polygons(pid_t)%vertices(vid_t+1)%y) ) &
3235	.OR. (is_right(x,y,x_t,y_t, &
3236	polygons(pid_t)%vertices(vid_t-1)%x, &
3237	polygons(pid_t)%vertices(vid_t-1)%y) &
3238	.AND. is_left(x,y,x_t,y_t, &
3239	polygons(pid_t)%vertices(vid_t+1)%x, &
3240	polygons(pid_t)%vertices(vid_t+1)%y)))))&
3241	THEN
3242	CYCLE
3243	ENDIF
3244	ENDIF
3245	!
3246	!-- For each edge of each polygon, check if it intersects with the
3247	!-- potential connection. If at least one intersection is found,
3248	!-- no connection can be made
3249	intersection_found = .FALSE.
3250	DO pl = 1, SIZE(polygons)
3251	DO vl = 1, polygons(pl)%nov
3252	v1x = polygons(pl)%vertices(vl)%x
3253	v1y = polygons(pl)%vertices(vl)%y
3254	v2x = polygons(pl)%vertices(vl+1)%x
3255	v2y = polygons(pl)%vertices(vl+1)%y
3256	intersection_found = intersect(x,y,x_t,y_t,v1x,v1y,v2x,v2y)
3257	IF ( intersection_found ) THEN
3258	EXIT
3259	ENDIF
3260	ENDDO
3261	IF ( intersection_found ) EXIT
3262	ENDDO
3263	IF ( intersection_found ) CYCLE
3264	!
3265	!-- If neither of the above two test was true, a connection will be
3266	!-- established between the two mesh points.
3267	CALL mas_nav_add_connection(in_mp,jl, tmp_mesh(jl))
3268	CALL mas_nav_add_connection(tmp_mesh(jl),in_id, in_mp)
3269	ENDDO
3270	CALL mas_nav_reduce_connections(in_mp)
3271
3272	END SUBROUTINE mas_nav_add_vertex_to_mesh
3273
3274	!------------------------------------------------------------------------------!
3275	! Description:
3276	! ------------
3277	!> Creates a temporary copy of the navigation mesh to be used for pathfinding
3278	!------------------------------------------------------------------------------!
3279	SUBROUTINE mas_nav_create_tmp_mesh( a_x, a_y, t_x, t_y, som )
3280
3281	IMPLICIT NONE
3282
3283	INTEGER(iwp) :: som !< size of mesh
3284	INTEGER(iwp) :: noc !< number of connetions
3285	INTEGER(iwp) :: im !< local mesh point counter
3286
3287	REAL(wp) :: a_x !< x-coordinate agent
3288	REAL(wp) :: a_y !< y-coordinate agent
3289	REAL(wp) :: t_x !< x-coordinate target
3290	REAL(wp) :: t_y !< y-coordinate target
3291	!
3292	!-- give tmp_mesh the size of mesh
3293	som = SIZE(mesh)+1
3294	ALLOCATE(tmp_mesh(0:som))
3295	!
3296	!-- give the allocatable variables in tmp_mesh their respctive sizes
3297	DO im = 1, som-1
3298	noc = mesh(im)%noc
3299	ALLOCATE(tmp_mesh(im)%connected_vertices(1:noc))
3300	ALLOCATE(tmp_mesh(im)%distance_to_vertex(1:noc))
3301	ENDDO
3302	!
3303	!-- copy mesh to tmp_mesh
3304	tmp_mesh(1:som-1) = mesh(1:som-1)
3305	!
3306	!-- Add target point ...
3307	CALL mas_nav_init_mesh_point(tmp_mesh(0),-1_iwp,-1_iwp,t_x, t_y)
3308	CALL mas_nav_add_vertex_to_mesh(tmp_mesh(0),0_iwp)
3309	!
3310	!-- ... and start point to temp mesh
3311	CALL mas_nav_init_mesh_point(tmp_mesh(som),-1_iwp,-1_iwp,a_x, a_y)
3312	CALL mas_nav_add_vertex_to_mesh(tmp_mesh(som),som)
3313
3314	END SUBROUTINE mas_nav_create_tmp_mesh
3315
3316	!------------------------------------------------------------------------------!
3317	! Description:
3318	! ------------
3319	!> Finds the shortest path from agent position to target using A*-algorithm
3320	!------------------------------------------------------------------------------!
3321	SUBROUTINE mas_nav_find_path( i_ag )
3322
3323	IMPLICIT NONE
3324
3325	LOGICAL :: target_reached !< flag
3326
3327	INTEGER(iwp) :: cur_node !< current node of binary heap
3328	INTEGER(iwp) :: i_ag !< agent index
3329	INTEGER(iwp) :: il !< counter (x)
3330	INTEGER(iwp) :: jl !< counter (y)
3331	INTEGER(iwp) :: neigh_node !< neighbor node
3332	INTEGER(iwp) :: node_counter !< binary heap node counter
3333	INTEGER(iwp) :: path_ag !< index of agent path
3334	INTEGER(iwp) :: som !< size of mesh
3335	INTEGER(iwp) :: rn_side !< index of agent path
3336	INTEGER(iwp) :: steps !< steps along the path
3337
3338	REAL(wp) :: a_x !< x-coordinate agent
3339	REAL(wp) :: a_y !< y-coordinate agent
3340	REAL(wp) :: new_cost !< updated cost to reach node
3341	REAL(wp) :: new_priority !< priority of node to be added to queue
3342	REAL(wp) :: rand_nr !< x-coordinate target
3343	REAL(wp) :: rn_gate !< random number for corner gate
3344	REAL(wp) :: t_x !< x-coordinate target
3345	REAL(wp) :: t_y !< y-coordinate target
3346	!
3347	!-- Coordinate Type
3348	TYPE coord
3349	REAL(wp) :: x !< x-coordinate
3350	REAL(wp) :: x_s !< x-coordinate (shifted)
3351	REAL(wp) :: y !< y-coordinate
3352	REAL(wp) :: y_s !< y-coordinate (shifted)
3353	END TYPE coord
3354
3355	TYPE(coord), DIMENSION(:), ALLOCATABLE, TARGET :: path !< path array
3356	TYPE(coord), DIMENSION(:), ALLOCATABLE, TARGET :: tmp_path !< temporary path for resizing
3357
3358	CALL cpu_log( log_point_s(20), 'mas_nav_find_path', 'start' )
3359	node_counter = 0
3360	a_x = agents(i_ag)%x
3361	a_y = agents(i_ag)%y
3362	t_x = agents(i_ag)%t_x
3363	t_y = agents(i_ag)%t_y
3364
3365	!
3366	!-- Create temporary navigation mesh including agent and target positions
3367	CALL mas_nav_create_tmp_mesh( a_x, a_y, t_x, t_y, som )
3368	tmp_mesh(som)%cost_so_far = 0.0_wp
3369	!
3370	!-- Initialize priority queue
3371	heap_count = 0_iwp
3372	ALLOCATE(queue(0:100))
3373	target_reached = .FALSE.
3374	!
3375	!-- Add starting point (agent position) to frontier (the frontier consists
3376	!-- of all the nodes that are to be visited. The node with the smallest
3377	!-- priority will be visited first. The priority consists of the distance
3378	!-- from the start node to this node plus a minimal guess (direct distance)
3379	!-- from this node to the goal). For the starting node, the priority is set
3380	!-- to 0, as it's the only node thus far
3381	CALL mas_heap_insert_item(som,0.0_wp)
3382	cur_node = som
3383	DO WHILE ( heap_count > 0 )
3384	!
3385	!-- Step one: Pick lowest priority item from queue
3386	node_counter = node_counter + 1
3387	CALL mas_heap_extract_item(cur_node)
3388	!
3389	!-- Node 0 is the goal node
3390	IF ( cur_node == 0 ) THEN
3391	EXIT
3392	ENDIF
3393	!
3394	!-- Loop over all of cur_node's neighbors
3395	DO il = 1, tmp_mesh(cur_node)%noc
3396	neigh_node = tmp_mesh(cur_node)%connected_vertices(il)
3397	!
3398	!-- Check, if the way from the start node to this neigh_node via
3399	!-- cur_node is shorter than the previously found shortest path to it.
3400	!-- If so, replace said cost and add neigh_node to the frontier.
3401	!-- cost_so_far is initialized as 1.d12 so that all found distances
3402	!-- should be smaller.
3403	new_cost = tmp_mesh(cur_node)%cost_so_far &
3404	+ tmp_mesh(cur_node)%distance_to_vertex(il)
3405	IF ( new_cost < tmp_mesh(neigh_node)%cost_so_far ) THEN
3406	tmp_mesh(neigh_node)%cost_so_far = new_cost
3407	tmp_mesh(neigh_node)%origin_id = cur_node
3408	!
3409	!-- Priority in the queue is cost_so_far + heuristic to goal
3410	new_priority = new_cost &
3411	+ heuristic(tmp_mesh(neigh_node)%x, &
3412	tmp_mesh(neigh_node)%y, tmp_mesh(0)%x, &
3413	tmp_mesh(0)%y)
3414	CALL mas_heap_insert_item(neigh_node,new_priority)
3415	ENDIF
3416	ENDDO
3417	ENDDO
3418	!
3419	!-- Pathfinding is done. Add nodes to a path array, then give the
3420	!-- first 15 intermittent targets to the agent.
3421	DEALLOCATE(queue)
3422	cur_node = 0
3423	steps = 0
3424	ALLOCATE(path(1:100))
3425	DO WHILE ( cur_node /= -1 )
3426	steps = steps + 1
3427	!
3428	!-- Resize path array if necessary
3429	IF ( steps > SIZE(path) ) THEN
3430	ALLOCATE(tmp_path(1:steps-1))
3431	tmp_path(1:steps-1) = path(1:steps-1)
3432	DEALLOCATE(path)
3433	ALLOCATE(path(1:2*(steps-1)))
3434	path(1:steps-1) = tmp_path(1:steps-1)
3435	DEALLOCATE(tmp_path)
3436	ENDIF
3437	path(steps)%x = tmp_mesh(cur_node)%x
3438	path(steps)%y = tmp_mesh(cur_node)%y
3439	path(steps)%x_s = tmp_mesh(cur_node)%x_s
3440	path(steps)%y_s = tmp_mesh(cur_node)%y_s
3441	cur_node = tmp_mesh(cur_node)%origin_id
3442	ENDDO
3443	!
3444	!-- Add calculated intermittent targets to agent path until either the
3445	!-- target or the maximum number of intermittent targets is reached.
3446	!-- Ignore starting point (reduce index by one), it is agent position.
3447	path_ag = 1
3448	steps = steps - 1
3449	DO WHILE( steps > 0 .AND. path_ag < SIZE(agents(i_ag)%path_x) )
3450	!
3451	!-- Each target point is randomly chosen along a line target along the
3452	!-- bisector of the building corner that starts at corner_gate_start
3453	!-- and has a width of corner_gate_width. This is to avoid clustering
3454	!-- when opposing agent groups try to reach the same corner target.
3455	rn_gate = random_function(iran_agent) * corner_gate_width &
3456	+ corner_gate_start
3457	agents(i_ag)%path_x(path_ag) = path(steps)%x + rn_gate &
3458	* (path(steps)%x_s - path(steps)%x)
3459	agents(i_ag)%path_y(path_ag) = path(steps)%y + rn_gate &
3460	* (path(steps)%y_s - path(steps)%y)
3461	steps = steps - 1
3462	path_ag = path_ag + 1
3463	ENDDO
3464	!
3465	!-- Set current intermittent target of this agent
3466	agents(i_ag)%path_counter = 1
3467	DEALLOCATE(tmp_mesh, path)
3468	CALL cpu_log( log_point_s(20), 'mas_nav_find_path', 'stop' )
3469
3470	END SUBROUTINE mas_nav_find_path
3471
3472	!------------------------------------------------------------------------------!
3473	! Description:
3474	! ------------
3475	!> Reduces the size of connection array to the amount of actual connections
3476	!> after all connetions were added to a mesh point
3477	!------------------------------------------------------------------------------!
3478	SUBROUTINE mas_nav_reduce_connections ( in_mp )
3479
3480	IMPLICIT NONE
3481
3482	INTEGER(iwp) :: noc !< number of connections
3483
3484	INTEGER, DIMENSION(:), ALLOCATABLE :: dum_cv !< dummy connected_vertices
3485
3486	REAL(wp), DIMENSION(:), ALLOCATABLE :: dum_dtv !< dummy distance_to_vertex
3487
3488	TYPE(mesh_point) :: in_mp
3489
3490	noc = in_mp%noc
3491	ALLOCATE( dum_cv(1:noc),dum_dtv(1:noc) )
3492	dum_cv = in_mp%connected_vertices(1:noc)
3493	dum_dtv = in_mp%distance_to_vertex(1:noc)
3494	DEALLOCATE( in_mp%connected_vertices, in_mp%distance_to_vertex )
3495	ALLOCATE( in_mp%connected_vertices(1:noc), &
3496	in_mp%distance_to_vertex(1:noc) )
3497	in_mp%connected_vertices(1:noc) = dum_cv(1:noc)
3498	in_mp%distance_to_vertex(1:noc) = dum_dtv(1:noc)
3499
3500	END SUBROUTINE mas_nav_reduce_connections
3501
3502	!------------------------------------------------------------------------------!
3503	! Description:
3504	! ------------
3505	!> Initializes a point of the navigation mesh
3506	!------------------------------------------------------------------------------!
3507	SUBROUTINE mas_nav_init_mesh_point ( in_mp, pid, vid, x, y )
3508
3509	IMPLICIT NONE
3510
3511	INTEGER(iwp) :: pid !< polygon ID
3512	INTEGER(iwp) :: vid !< vertex ID
3513
3514	REAL(wp) :: x !< x-coordinate
3515	REAL(wp) :: y !< y-coordinate
3516
3517	TYPE(mesh_point) :: in_mp !< mesh point to be initialized
3518
3519	in_mp%origin_id = -1
3520	in_mp%polygon_id = pid
3521	in_mp%vertex_id = vid
3522	in_mp%cost_so_far = 1.d12
3523	in_mp%x = x
3524	in_mp%y = y
3525	in_mp%x_s = x
3526	in_mp%y_s = y
3527	ALLOCATE(in_mp%connected_vertices(1:100), &
3528	in_mp%distance_to_vertex(1:100))
3529	in_mp%connected_vertices = -999
3530	in_mp%distance_to_vertex = -999.
3531	in_mp%noc = 0
3532
3533	END SUBROUTINE mas_nav_init_mesh_point
3534
3535	!------------------------------------------------------------------------------!
3536	! Description:
3537	! ------------
3538	!> Reading of namlist from parin file
3539	!------------------------------------------------------------------------------!
3540	SUBROUTINE mas_parin
3541
3542	USE control_parameters, &
3543	ONLY: agent_time_unlimited
3544
3545	IMPLICIT NONE
3546
3547	CHARACTER (LEN=80) :: line !<
3548
3549	NAMELIST /agents_par/ a_rand_target, adx, ady, agent_maximum_age, &
3550	agent_time_unlimited, alloc_factor_mas, asl, asn,&
3551	asr, ass, at_x, at_y, bc_mas_lr, bc_mas_ns, &
3552	coll_t_0, corner_gate_start, corner_gate_width, &
3553	deallocate_memory_mas, dist_to_int_target, &
3554	dt_agent, dt_arel, dt_write_agent_data,&
3555	end_time_arel, max_dist_from_path, min_nr_agent, &
3556	multi_agent_system_start, number_of_agent_groups,&
3557	radius_agent, random_start_position_agents, &
3558	read_agents_from_restartfile, repuls_agent, &
3559	repuls_wall, scan_radius_agent, sigma_rep_agent, &
3560	sigma_rep_wall, step_dealloc_mas, tau_accel_agent
3561
3562	!
3563	!-- Try to find agent package
3564	REWIND ( 11 )
3565	line = ' '
3566	DO WHILE ( INDEX( line, '&agents_par' ) == 0 )
3567	READ ( 11, '(A)', END=20 ) line
3568	ENDDO
3569	BACKSPACE ( 11 )
3570
3571	!
3572	!-- Read user-defined namelist
3573	READ ( 11, agents_par )
3574
3575	!
3576	!-- Set flag that indicates that agents are switched on
3577	agents_active = .TRUE.
3578
3579	20 CONTINUE
3580
3581	END SUBROUTINE mas_parin
3582
3583	!------------------------------------------------------------------------------!
3584	! Description:
3585	! ------------
3586	!> Routine for the whole processor
3587	!> Sort all agents into the 4 respective subgrid boxes
3588	!------------------------------------------------------------------------------!
3589	SUBROUTINE mas_ps_sort_in_subboxes
3590
3591	IMPLICIT NONE
3592
3593	INTEGER(iwp) :: i !< grid box (x)
3594	INTEGER(iwp) :: ip !< counter (x)
3595	INTEGER(iwp) :: is !< box counter
3596	INTEGER(iwp) :: j !< grid box (y)
3597	INTEGER(iwp) :: jp !< counter (y)
3598	INTEGER(iwp) :: m !< sorting index
3599	INTEGER(iwp) :: n !< agent index
3600	INTEGER(iwp) :: nn !< agent counter
3601	INTEGER(iwp) :: sort_index !< sorting index
3602
3603	INTEGER(iwp), DIMENSION(0:3) :: sort_count !< number of agents in one subbox
3604
3605	TYPE(agent_type), DIMENSION(:,:), ALLOCATABLE :: sort_agents !< sorted agent array
3606
3607	CALL cpu_log( log_point_s(21), 'mas_ps_sort_in_subboxes', 'start' )
3608	DO ip = nxl, nxr
3609	DO jp = nys, nyn
3610	number_of_agents = agt_count(jp,ip)
3611	IF ( number_of_agents <= 0 ) CYCLE
3612	agents => grid_agents(jp,ip)%agents(1:number_of_agents)
3613
3614	nn = 0
3615	sort_count = 0
3616	ALLOCATE( sort_agents(number_of_agents, 0:3) )
3617
3618	DO n = 1, number_of_agents
3619	sort_index = 0
3620
3621	IF ( agents(n)%agent_mask ) THEN
3622	nn = nn + 1
3623	!
3624	!-- Sorting agents with a binary scheme
3625	!-- sort_index=11_2=3_10 -> agent at the left,south subgridbox
3626	!-- sort_index=10_2=2_10 -> agent at the left,north subgridbox
3627	!-- sort_index=01_2=1_10 -> agent at the right,south subgridbox
3628	!-- sort_index=00_2=0_10 -> agent at the right,north subgridbox
3629	!-- For this the center of the gridbox is calculated
3630	i = (agents(n)%x + 0.5_wp * dx) * ddx
3631	j = (agents(n)%y + 0.5_wp * dy) * ddy
3632
3633	IF ( i == ip ) sort_index = sort_index + 2
3634	IF ( j == jp ) sort_index = sort_index + 1
3635
3636	sort_count(sort_index) = sort_count(sort_index) + 1
3637	m = sort_count(sort_index)
3638	sort_agents(m,sort_index) = agents(n)
3639	sort_agents(m,sort_index)%block_nr = sort_index
3640	ENDIF
3641	ENDDO
3642
3643	nn = 0
3644	DO is = 0,3
3645	grid_agents(jp,ip)%start_index(is) = nn + 1
3646	DO n = 1,sort_count(is)
3647	nn = nn + 1
3648	agents(nn) = sort_agents(n,is)
3649	ENDDO
3650	grid_agents(jp,ip)%end_index(is) = nn
3651	ENDDO
3652
3653	number_of_agents = nn
3654	agt_count(jp,ip) = number_of_agents
3655	DEALLOCATE(sort_agents)
3656	ENDDO
3657	ENDDO
3658	CALL cpu_log( log_point_s(21), 'mas_ps_sort_in_subboxes', 'stop' )
3659
3660	END SUBROUTINE mas_ps_sort_in_subboxes
3661
3662	!------------------------------------------------------------------------------!
3663	! Description:
3664	! ------------
3665	!> Move all agents not marked for deletion to lowest indices (packing)
3666	!------------------------------------------------------------------------------!
3667	SUBROUTINE mas_ps_pack
3668
3669	IMPLICIT NONE
3670
3671	INTEGER(iwp) :: n !< agent counter
3672	INTEGER(iwp) :: nn !< number of agents
3673	!
3674	!-- Find out elements marked for deletion and move data from highest index
3675	!-- values to these free indices
3676	nn = number_of_agents
3677
3678	DO WHILE ( .NOT. agents(nn)%agent_mask )
3679	nn = nn-1
3680	IF ( nn == 0 ) EXIT
3681	ENDDO
3682
3683	IF ( nn > 0 ) THEN
3684	DO n = 1, number_of_agents
3685	IF ( .NOT. agents(n)%agent_mask ) THEN
3686	agents(n) = agents(nn)
3687	nn = nn - 1
3688	DO WHILE ( .NOT. agents(nn)%agent_mask )
3689	nn = nn-1
3690	IF ( n == nn ) EXIT
3691	ENDDO
3692	ENDIF
3693	IF ( n == nn ) EXIT
3694	ENDDO
3695	ENDIF
3696
3697	!
3698	!-- The number of deleted agents has been determined in routines
3699	!-- mas_boundary_conds, mas_droplet_collision, and mas_eh_exchange_horiz
3700	number_of_agents = nn
3701
3702	END SUBROUTINE mas_ps_pack
3703
3704	!------------------------------------------------------------------------------!
3705	! Description:
3706	! ------------
3707	!> Sort agents in each sub-grid box into two groups: agents that already
3708	!> completed the LES timestep, and agents that need further timestepping to
3709	!> complete the LES timestep.
3710	!------------------------------------------------------------------------------!
3711	SUBROUTINE mas_ps_sort_timeloop_done
3712
3713	IMPLICIT NONE
3714
3715	INTEGER(iwp) :: end_index !< agent end index for each sub-box
3716	INTEGER(iwp) :: i !< index of agent grid box in x-direction
3717	INTEGER(iwp) :: j !< index of agent grid box in y-direction
3718	INTEGER(iwp) :: n !< running index for number of agents
3719	INTEGER(iwp) :: nb !< index of subgrid boux
3720	INTEGER(iwp) :: nf !< indices for agents in each sub-box that already finalized their substeps
3721	INTEGER(iwp) :: nnf !< indices for agents in each sub-box that need further treatment
3722	INTEGER(iwp) :: num_finalized !< number of agents in each sub-box that already finalized their substeps
3723	INTEGER(iwp) :: start_index !< agent start index for each sub-box
3724
3725	TYPE(agent_type), DIMENSION(:), ALLOCATABLE :: sort_agents !< temporary agent array
3726
3727	DO i = nxl, nxr
3728	DO j = nys, nyn
3729
3730	number_of_agents = agt_count(j,i)
3731	IF ( number_of_agents <= 0 ) CYCLE
3732
3733	agents => grid_agents(j,i)%agents(1:number_of_agents)
3734
3735	DO nb = 0, 3
3736	!
3737	!-- Obtain start and end index for each subgrid box
3738	start_index = grid_agents(j,i)%start_index(nb)
3739	end_index = grid_agents(j,i)%end_index(nb)
3740	!
3741	!-- Allocate temporary array used for sorting
3742	ALLOCATE( sort_agents(start_index:end_index) )
3743	!
3744	!-- Determine number of agents already completed the LES
3745	!-- timestep, and write them into a temporary array
3746	nf = start_index
3747	num_finalized = 0
3748	DO n = start_index, end_index
3749	IF ( dt_3d - agents(n)%dt_sum < 1E-8_wp ) THEN
3750	sort_agents(nf) = agents(n)
3751	nf = nf + 1
3752	num_finalized = num_finalized + 1
3753	ENDIF
3754	ENDDO
3755	!
3756	!-- Determine number of agents that not completed the LES
3757	!-- timestep, and write them into a temporary array
3758	nnf = nf
3759	DO n = start_index, end_index
3760	IF ( dt_3d - agents(n)%dt_sum > 1E-8_wp ) THEN
3761	sort_agents(nnf) = agents(n)
3762	nnf = nnf + 1
3763	ENDIF
3764	ENDDO
3765	!
3766	!-- Write back sorted agents
3767	agents(start_index:end_index) = &
3768	sort_agents(start_index:end_index)
3769	!
3770	!-- Determine updated start_index, used to masked already
3771	!-- completed agents.
3772	grid_agents(j,i)%start_index(nb) = &
3773	grid_agents(j,i)%start_index(nb) &
3774	+ num_finalized
3775	!
3776	!-- Deallocate dummy array
3777	DEALLOCATE ( sort_agents )
3778	!
3779	!-- Finally, if number of non-completed agents is non zero
3780	!-- in any of the sub-boxes, set control flag appropriately.
3781	IF ( nnf > nf ) &
3782	grid_agents(j,i)%time_loop_done = .FALSE.
3783
3784	ENDDO
3785	ENDDO
3786	ENDDO
3787
3788	END SUBROUTINE mas_ps_sort_timeloop_done
3789
3790	!------------------------------------------------------------------------------!
3791	! Description:
3792	! ------------
3793	!> Calls social forces calculations
3794	!------------------------------------------------------------------------------!
3795	SUBROUTINE mas_timestep_forces_call ( ip, jp )
3796
3797	IMPLICIT NONE
3798
3799	INTEGER(iwp) :: ip !< counter, x-direction
3800	INTEGER(iwp) :: jp !< counter, y-direction
3801	INTEGER(iwp) :: n !< loop variable over all agents in a grid box
3802
3803	!
3804	!-- Get direction for all agents in current grid cell
3805	CALL mas_agent_direction
3806
3807	CALL cpu_log( log_point_s(9), 'mas_transport', 'continue' )
3808	DO n = 1, number_of_agents
3809
3810	force_x = 0.0_wp
3811	force_y = 0.0_wp
3812
3813	CALL mas_timestep_social_forces ( 'acceleration', n, ip, jp )
3814
3815	CALL mas_timestep_social_forces ( 'other_agents', n, ip, jp )
3816
3817	CALL mas_timestep_social_forces ( 'walls', n, ip, jp )
3818	!
3819	!-- Update forces
3820	agents(n)%force_x = force_x
3821	agents(n)%force_y = force_y
3822	ENDDO
3823
3824	CALL cpu_log( log_point_s(9), 'mas_transport', 'pause' )
3825
3826
3827	END SUBROUTINE mas_timestep_forces_call
3828
3829	!------------------------------------------------------------------------------!
3830	! Description:
3831	! ------------
3832	!> Euler timestep of agent transport
3833	!------------------------------------------------------------------------------!
3834	SUBROUTINE mas_timestep
3835
3836	IMPLICIT NONE
3837
3838	INTEGER(iwp) :: n !< loop variable over all agents in a grid box
3839
3840	REAL(wp) :: abs_v !< absolute value of velocity
3841	REAL(wp) :: abs_f !< absolute value of force
3842
3843	CALL cpu_log( log_point_s(9), 'mas_transport', 'continue' )
3844
3845	DO n = 1, number_of_agents
3846	!
3847	!-- Limit absolute force to a maximum to prevent unrealistic acceleration
3848	abs_f = SQRT((agents(n)%force_x)2 + (agents(n)%force_y)2)
3849	IF ( abs_f > 20. ) THEN
3850	agents(n)%force_x = agents(n)%force_x * 20. / abs_f
3851	agents(n)%force_y = agents(n)%force_y * 20. / abs_f
3852	ENDIF
3853	!
3854	!-- Update agent speed
3855	agents(n)%speed_x = agents(n)%speed_x + agents(n)%force_x * dt_agent
3856	agents(n)%speed_y = agents(n)%speed_y + agents(n)%force_y * dt_agent
3857	!
3858	!-- Reduction of agent speed to maximum agent speed
3859	abs_v = SQRT((agents(n)%speed_x)2 + (agents(n)%speed_y)2)
3860	IF ( abs_v > v_max_agent ) THEN
3861	agents(n)%speed_x = agents(n)%speed_x * v_max_agent / abs_v
3862	agents(n)%speed_y = agents(n)%speed_y * v_max_agent / abs_v
3863	ENDIF
3864	!
3865	!-- Update agent position
3866	agents(n)%x = agents(n)%x + agents(n)%speed_x * dt_agent
3867	agents(n)%y = agents(n)%y + agents(n)%speed_y * dt_agent
3868	!
3869	!-- Update absolute value of agent speed
3870	agents(n)%speed_abs = abs_v
3871	!
3872	!-- Increment the agent age and the total time that the agent
3873	!-- has advanced within the agent timestep procedure
3874	agents(n)%age_m = agents(n)%age
3875	agents(n)%age = agents(n)%age + dt_agent
3876	agents(n)%dt_sum = agents(n)%dt_sum + dt_agent
3877	!
3878	!-- Check whether there is still an agent that has not yet completed
3879	!-- the total LES timestep
3880	IF ( ( dt_3d - agents(n)%dt_sum ) > 1E-8_wp ) THEN
3881	dt_3d_reached_l_mas = .FALSE.
3882	ENDIF
3883
3884	ENDDO
3885
3886	CALL cpu_log( log_point_s(9), 'mas_transport', 'pause' )
3887
3888
3889	END SUBROUTINE mas_timestep
3890
3891	!------------------------------------------------------------------------------!
3892	! Description:
3893	! ------------
3894	!> Calculates the Social Forces (Helbing and Molnar, 1995) that the agent
3895	!> experiences due to acceleration towards target and repulsion by obstacles
3896	!------------------------------------------------------------------------------!
3897	SUBROUTINE mas_timestep_social_forces ( mode, nl, ip, jp )
3898
3899	USE constants, &
3900	ONLY: pi
3901
3902	IMPLICIT NONE
3903
3904	CHARACTER (LEN=*) :: mode !< identifier for the mode of calculation
3905
3906	INTEGER(iwp) :: ij_dum !< index of nearest wall
3907	INTEGER(iwp) :: il !< index variable along x
3908	INTEGER(iwp) :: ip !< index variable along x
3909	INTEGER(iwp) :: jl !< index variable along y
3910	INTEGER(iwp) :: jp !< index variable along y
3911	INTEGER(iwp) :: nl !< loop variable over all agents in a grid box
3912	INTEGER(iwp) :: no !< loop variable over all agents in a grid box
3913	INTEGER(iwp) :: noa !< amount of agents in a grid box
3914	INTEGER(iwp) :: sc_x_end !< index for scan for topography/other agents
3915	INTEGER(iwp) :: sc_x_start !< index for scan for topography/other agents
3916	INTEGER(iwp) :: sc_y_end !< index for scan for topography/other agents
3917	INTEGER(iwp) :: sc_y_start !< index for scan for topography/other agents
3918
3919	LOGICAL :: corner_found !< flag that indicates a corner has been found near agent
3920
3921	REAL(wp) :: a_pl !< factor for collision avoidance
3922	REAL(wp) :: ax_semimaj !< semiminor axis of repulsive ellipse
3923	REAL(wp) :: b_pl !< factor for collision avoidance
3924	REAL(wp) :: c_pl !< factor for collision avoidance
3925	REAL(wp) :: coll_t !< time at which the next collision would happen
3926	REAL(wp) :: d_coll_t_0 !< inverse of collision cutoff time
3927	REAL(wp) :: d_pl !< factor for collision avoidance
3928	REAL(wp) :: ddum_f !< dummy devisor collision avoidance
3929	REAL(wp) :: dist !< distance to obstacle
3930	REAL(wp) :: dist_sq !< distance to obstacle squared
3931	REAL(wp) :: dummy_coll_time !< dummy for collision time
3932	REAL(wp) :: pos_rel_x !< relative position of two agents (x)
3933	REAL(wp) :: pos_rel_y !< relative position of two agents (y)
3934	REAL(wp) :: r_sq !< y-position
3935	REAL(wp) :: sra !< scan radius (agents)
3936	REAL(wp) :: srw !< local variable for scan radius (walls)
3937	REAL(wp) :: v_rel_x !< relative velocity (x); collision avoidance
3938	REAL(wp) :: v_rel_y !< relative velocity (y); collision avoidance
3939	REAL(wp) :: x_a !< x-position
3940	REAL(wp) :: x_wall !< x-position of wall
3941	REAL(wp) :: y_a !< y-position
3942	REAL(wp) :: y_wall !< y-position of wall
3943
3944	REAL(wp), PARAMETER :: k_pl = 1.5 !< factor for collision avoidance
3945
3946	TYPE(agent_type), DIMENSION(:), POINTER :: l_agts !< agents that repulse current agent
3947
3948	!
3949	!-- Initialization
3950	x_a = agents(nl)%x
3951	y_a = agents(nl)%y
3952
3953	SELECT CASE ( TRIM( mode ) )
3954	!
3955	!-- Calculation of force due to agent trying to approach desired velocity
3956	CASE ( 'acceleration' )
3957
3958	force_x = force_x + d_tau_accel_agent &
3959	* ( agents(nl)%speed_des*agents(nl)%speed_e_x &
3960	-agents(nl)%speed_x )
3961
3962	force_y = force_y + d_tau_accel_agent &
3963	* ( agents(nl)%speed_des*agents(nl)%speed_e_y &
3964	-agents(nl)%speed_y )
3965
3966	!
3967	!-- Calculation of repulsive forces by other agents in a radius around the
3968	!-- current one
3969	CASE ( 'other_agents' )
3970	CALL cpu_log( log_point_s(16), 'mas_other_agents', 'continue' )
3971
3972	sra = scan_radius_agent
3973	d_coll_t_0 = 1./coll_t_0
3974	!
3975	!-- Find relevant gridboxes (those that could contain agents within
3976	!-- scan radius)
3977	sc_x_start = FLOOR( (x_a - sra) * ddx )
3978	sc_x_end = FLOOR( (x_a + sra) * ddx )
3979	sc_y_start = FLOOR( (y_a - sra) * ddx )
3980	sc_y_end = FLOOR( (y_a + sra) * ddx )
3981	IF ( sc_x_start < nxlg ) sc_x_start = nxlg
3982	IF ( sc_x_end > nxrg ) sc_x_end = nxrg
3983	IF ( sc_y_start < nysg ) sc_y_start = nysg
3984	IF ( sc_y_end > nyng ) sc_y_end = nyng
3985
3986	sra = sra**2
3987	!
3988	!-- Loop over all previously found relevant gridboxes
3989	DO il = sc_x_start, sc_x_end
3990	DO jl = sc_y_start, sc_y_end
3991	noa = agt_count(jl,il)
3992	IF ( noa <= 0 ) CYCLE
3993	l_agts => grid_agents(jl,il)%agents(1:noa)
3994	DO no = 1, noa
3995	!
3996	!-- Skip self
3997	IF ( jl == jp .AND. il == ip .AND. no == nl ) CYCLE
3998	pos_rel_x = l_agts(no)%x - x_a
3999	pos_rel_y = l_agts(no)%y - y_a
4000	dist_sq = pos_rel_x2 + pos_rel_y2
4001	IF ( dist_sq > sra ) CYCLE
4002	r_sq = (2radius_agent)*2
4003	v_rel_x = agents(nl)%speed_x - l_agts(no)%speed_x
4004	v_rel_y = agents(nl)%speed_y - l_agts(no)%speed_y
4005	!
4006	!-- Collision is already occuring, default to standard
4007	!-- social forces
4008	IF ( dist_sq <= r_sq ) THEN
4009	dist = SQRT(dist_sq) + 1.0d-12
4010	ax_semimaj = .5_wp*SQRT( dist )
4011
4012	force_x = force_x - 0.125_wp * repuls_agent &
4013	* d_sigma_rep_agent / ax_semimaj &
4014	* EXP( -ax_semimaj*d_sigma_rep_agent ) &
4015	* (pos_rel_x/dist)
4016
4017	force_y = force_y - 0.125_wp * repuls_agent &
4018	* d_sigma_rep_agent / ax_semimaj &
4019	* EXP( -ax_semimaj*d_sigma_rep_agent ) &
4020	* (pos_rel_y/dist)
4021	!
4022	!-- Currently no collision, calculate collision avoidance
4023	!-- force according to Karamouzas et al (2014, PRL 113,238701)
4024	ELSE
4025	!
4026	!-- factors
4027	a_pl = v_rel_x2 + v_rel_y2
4028	b_pl = pos_rel_xv_rel_x + pos_rel_yv_rel_y
4029	c_pl = dist_sq - r_sq
4030	d_pl = b_pl*2 - a_plc_pl
4031	!
4032	!-- If the two agents are moving non-parallel, calculate
4033	!-- collision avoidance social force
4034	IF ( d_pl > 0.0_wp .AND. &
4035	( a_pl < -0.00001 .OR. a_pl > 0.00001 ) ) &
4036	THEN
4037
4038	d_pl = SQRT(d_pl)
4039	coll_t = (b_pl - d_pl)/a_pl
4040	IF ( coll_t > 0.0_wp ) THEN
4041	!
4042	!-- Dummy factor
4043	ddum_f = 1. / ( a_pl * coll_t**2 ) &
4044	* ( 2. / coll_t + 1.0 * d_coll_t_0 )
4045	!
4046	!-- x-component of social force
4047	force_x = force_x - k_pl * &
4048	EXP( -coll_t * d_coll_t_0 ) * &
4049	( v_rel_x - &
4050	( b_pl * v_rel_x - &
4051	a_pl * pos_rel_x ) / d_pl ) * &
4052	ddum_f
4053	!
4054	!-- y-component of social force
4055	force_y = force_y - k_pl * &
4056	EXP( -coll_t * d_coll_t_0 ) * &
4057	( v_rel_y - &
4058	( b_pl * v_rel_y - &
4059	a_pl * pos_rel_y ) / d_pl ) * &
4060	ddum_f
4061
4062	ENDIF
4063	ENDIF
4064	ENDIF
4065	ENDDO
4066	ENDDO
4067	ENDDO
4068	CALL cpu_log( log_point_s(16), 'mas_other_agents', 'pause' )
4069
4070	CASE ( 'walls' )
4071
4072	srw = scan_radius_wall
4073	corner_found = .FALSE.
4074	!
4075	!-- find relevant grid boxes (those that could contain topography
4076	!-- within radius)
4077	sc_x_start = (x_a - srw) * ddx
4078	sc_x_end = (x_a + srw) * ddx
4079	sc_y_start = (y_a - srw) * ddx
4080	sc_y_end = (y_a + srw) * ddx
4081	IF ( sc_x_start < nxlg ) sc_x_start = nxlg
4082	IF ( sc_x_end > nxrg ) sc_x_end = nxrg
4083	IF ( sc_y_start < nysg ) sc_y_start = nysg
4084	IF ( sc_y_end > nyng ) sc_y_end = nyng
4085	!
4086	!-- Find "walls" ( i.e. topography steps (up or down) higher than one
4087	!-- grid box ) that are perpendicular to the agent within the defined
4088	!-- search radius. Such obstacles cannot be passed and a social force
4089	!-- to that effect is applied.
4090	!-- Walls only apply a force perpendicular to the wall to the agent.
4091	!-- There is therefore a search for walls directly right, left, south
4092	!-- and north of the agent. All other walls are ignored.
4093	!--
4094	!-- Check for wall left of current agent
4095	ij_dum = 0
4096	IF ( sc_x_start < ip ) THEN
4097	DO il = ip - 1, sc_x_start, -1
4098	!
4099	!-- Going left from the agent, check for a right wall
4100	IF ( BTEST( obstacle_flags(jp,il), 2 ) ) THEN
4101	!
4102	!-- obstacle found in grid box il, wall at right side
4103	x_wall = (il+1)*dx
4104	!
4105	!-- Calculate force of found wall on agent
4106	CALL mas_timestep_wall_corner_force ( nl, x_a, x_wall, &
4107	y_a, y_a )
4108	!
4109	!-- calculate new x starting index for later scan for corners
4110	ij_dum = il + 1
4111	EXIT
4112	ENDIF
4113	ENDDO
4114	ENDIF
4115	IF ( ij_dum /= 0 ) sc_x_start = ij_dum
4116
4117	!
4118	!-- Check for wall right of current agent
4119	ij_dum = 0
4120	IF ( sc_x_end > ip ) THEN
4121	DO il = ip + 1, sc_x_end
4122	!
4123	!-- Going right from the agent, check for a left wall
4124	IF ( BTEST( obstacle_flags(jp,il), 6 ) ) THEN
4125	!
4126	!-- obstacle found in grid box il, wall at left side
4127	x_wall = il*dx
4128	!
4129	!-- Calculate force of found wall on agent
4130	CALL mas_timestep_wall_corner_force ( nl, x_a, x_wall, &
4131	y_a, y_a )
4132	!
4133	!-- calculate new x end index for later scan for corners
4134	ij_dum = il - 1
4135	EXIT
4136	ENDIF
4137	ENDDO
4138	ENDIF
4139	IF ( ij_dum /= 0 ) sc_x_end = ij_dum
4140
4141	!
4142	!-- Check for wall south of current agent
4143	ij_dum = 0
4144	IF ( sc_y_start < jp ) THEN
4145	DO jl = jp - 1, sc_y_start, -1
4146	!
4147	!-- Going south from the agent, check for a north wall
4148	IF ( BTEST( obstacle_flags(jl,ip), 0 ) ) THEN
4149	!
4150	!-- obstacle found in grid box jl, wall at left side
4151	y_wall = (jl+1)*dy
4152
4153	CALL mas_timestep_wall_corner_force ( nl, x_a, x_a, y_a, &
4154	y_wall )
4155	!
4156	!-- calculate new y starting index for later scan for corners
4157	ij_dum = jl + 1
4158	EXIT
4159	ENDIF
4160	ENDDO
4161	ENDIF
4162	IF ( ij_dum /= 0 ) sc_y_start = ij_dum
4163
4164	!
4165	!-- Check for wall north of current agent
4166	ij_dum = 0
4167	IF ( sc_y_end > jp ) THEN
4168	DO jl = jp + 1, sc_y_end
4169	!
4170	!-- Going north from the agent, check for a south wall
4171	IF ( BTEST( obstacle_flags(jl,ip), 4 ) ) THEN
4172	!
4173	!-- obstacle found in grid box jl, wall at left side
4174	y_wall = jl*dy
4175
4176	CALL mas_timestep_wall_corner_force ( nl, x_a, x_a, y_a, &
4177	y_wall )
4178	!
4179	!-- calculate new y end index for later scan for corners
4180	ij_dum = jl - 1
4181	ENDIF
4182	ENDDO
4183	ENDIF
4184	IF ( ij_dum /= 0 ) sc_y_end = ij_dum
4185
4186	!
4187	!-- Scan for corners surrounding current agent.
4188	!-- Only gridcells that are closer than the closest wall in each
4189	!-- direction (n,s,r,l) are considered in the search since those
4190	!-- further away would have a significantly smaller resulting force
4191	!-- than the closer wall.
4192	DO il = sc_x_start, sc_x_end
4193	DO jl = sc_y_start, sc_y_end
4194	IF ( il == ip .OR. jl == jp ) CYCLE
4195	!
4196	!-- corners left of agent
4197	IF ( il < ip ) THEN
4198	!
4199	!-- south left quadrant: look for north right corner
4200	IF ( jl < jp ) THEN
4201	IF ( BTEST( obstacle_flags(jl,il), 1 ) ) THEN
4202	!
4203	!-- calculate coordinates of the found corner
4204	x_wall = (il+1)*dx
4205	y_wall = (jl+1)*dy
4206
4207	CALL mas_timestep_wall_corner_force ( nl, x_a, &
4208	x_wall, y_a, y_wall )
4209
4210	ENDIF
4211	!
4212	!-- north left quadrant: look for south right corner
4213	ELSEIF ( jl > jp ) THEN
4214	IF ( BTEST( obstacle_flags(jl,il), 3 ) ) THEN
4215	!
4216	!-- calculate coordinates of the corner of said gridcell
4217	!-- that is closest to the current agent
4218	x_wall = (il+1)*dx
4219	y_wall = jl*dy
4220
4221	CALL mas_timestep_wall_corner_force ( nl, x_a, &
4222	x_wall, y_a, y_wall )
4223
4224	ENDIF
4225	ENDIF
4226	ELSEIF ( il > ip ) THEN
4227	!
4228	!-- south right quadrant: look for north left corner
4229	IF ( jl < jp ) THEN
4230	IF ( BTEST( obstacle_flags(jl,il), 7 ) ) THEN
4231	!
4232	!-- calculate coordinates of the corner of said gridcell
4233	!-- that is closest to the current agent
4234	x_wall = il*dx
4235	y_wall = (jl+1)*dy
4236
4237	CALL mas_timestep_wall_corner_force ( nl, x_a, &
4238	x_wall, y_a, y_wall )
4239
4240	ENDIF
4241	!
4242	!-- north right quadrant: look for south left corner
4243	ELSEIF ( jl > jp ) THEN
4244	IF ( BTEST( obstacle_flags(jl,il), 5 ) ) THEN
4245	!
4246	!-- calculate coordinates of the corner of said gridcell
4247	!-- that is closest to the current agent
4248	x_wall = il*dx
4249	y_wall = jl*dy
4250
4251	CALL mas_timestep_wall_corner_force ( nl, x_a, &
4252	x_wall, y_a, y_wall )
4253
4254	ENDIF
4255	ENDIF
4256	ENDIF
4257	ENDDO
4258	ENDDO
4259
4260	CASE DEFAULT
4261
4262	END SELECT
4263
4264	END SUBROUTINE mas_timestep_social_forces
4265
4266	!------------------------------------------------------------------------------!
4267	! Description:
4268	! ------------
4269	!> Given a distance to the current agent, calculates the force a found corner
4270	!> or wall exerts on that agent
4271	!------------------------------------------------------------------------------!
4272	SUBROUTINE mas_timestep_wall_corner_force ( nl, xa, xw, ya, yw )
4273
4274	IMPLICIT NONE
4275
4276	INTEGER(iwp) :: nl !< loop variable over all agents in a grid box
4277
4278	REAL(wp) :: dist_l !< distance to obstacle
4279	REAL(wp) :: force_d_x !< increment of social force, x-direction
4280	REAL(wp) :: force_d_y !< increment of social force, x-direction
4281	REAL(wp) :: xa !< x-position of agent
4282	REAL(wp) :: xw !< x-position of wall
4283	REAL(wp) :: ya !< x-position of agent
4284	REAL(wp) :: yw !< y-position of wall
4285
4286	force_d_x = 0.0_wp
4287	force_d_y = 0.0_wp
4288	!
4289	!-- calculate coordinates of corner relative to agent
4290	!-- postion and distance between corner and agent
4291	xw = xa - xw
4292	yw = ya - yw
4293	dist_l = SQRT( (xw)2 + (yw)2 )
4294	!
4295	!-- calculate x and y component of repulsive force
4296	!-- induced by previously found corner
4297	IF ( dist_l > 0 ) THEN
4298	force_d_x = repuls_wall * d_sigma_rep_wall &
4299	* EXP( -dist_l * d_sigma_rep_wall ) &
4300	* xw / (dist_l)
4301	force_d_y = repuls_wall * d_sigma_rep_wall &
4302	* EXP( -dist_l * d_sigma_rep_wall ) &
4303	* yw / (dist_l)
4304	ENDIF
4305
4306	! !-- forces that are located outside of a sight radius of
4307	! !-- 200Â° (-> COS(100./180.pi) = COS(.555pi)) of
4308	! !-- current agent are considered to have an effect of 50%
4309	! IF ( force_d_x * agents(nl)%speed_e_x + &
4310	! force_d_y * agents(nl)%speed_e_y < &
4311	! SQRT(force_d_x2 + force_d_y2) * &
4312	! COS( .55555555 * 3.1415 ) ) &
4313	! THEN
4314	! force_d_x = force_d_x * .5_wp
4315	! force_d_y = force_d_y * .5_wp
4316	! ENDIF
4317
4318	!
4319	!-- add force increment to total force of current agent
4320	force_x = force_x + force_d_x
4321	force_y = force_y + force_d_y
4322
4323	END SUBROUTINE mas_timestep_wall_corner_force
4324
4325	!
4326	!-- Calculates distance of point P to edge (A,B). If A = B, calculates
4327	!-- point-to-point distance from A/B to P
4328	FUNCTION dist_point_to_edge ( a_x, a_y, b_x, b_y, p_x, p_y )
4329
4330	IMPLICIT NONE
4331
4332	REAL(wp) :: ab_x !< x-coordinate of vector from A to B
4333	REAL(wp) :: ab_y !< y-coordinate of vector from A to B
4334	REAL(wp) :: ab_d !< inverse length of vector from A to B
4335	REAL(wp) :: ab_u_x !< x-coordinate of vector with direction of ab and length 1
4336	REAL(wp) :: ab_u_y !< y-coordinate of vector with direction of ab and length 1
4337	REAL(wp) :: ba_x !< x-coordinate of vector from B to A
4338	REAL(wp) :: ba_y !< y-coordinate of vector from B to A
4339	REAL(wp) :: ap_x !< x-coordinate of vector from A to P
4340	REAL(wp) :: ap_y !< y-coordinate of vector from A to P
4341	REAL(wp) :: bp_x !< x-coordinate of vector from B to P
4342	REAL(wp) :: bp_y !< y-coordinate of vector from B to P
4343	REAL(wp) :: a_x !< x-coordinate of point A of edge
4344	REAL(wp) :: a_y !< y-coordinate of point A of edge
4345	REAL(wp) :: b_x !< x-coordinate of point B of edge
4346	REAL(wp) :: b_y !< y-coordinate of point B of edge
4347	REAL(wp) :: p_x !< x-coordinate of point P
4348	REAL(wp) :: p_y !< y-coordinate of point P
4349	REAL(wp) :: dist_x !< x-coordinate of point P
4350	REAL(wp) :: dist_y !< y-coordinate of point P
4351	REAL(wp) :: dist_point_to_edge !< y-coordinate of point P
4352
4353	ab_x = - a_x + b_x
4354	ab_y = - a_y + b_y
4355	ba_x = - b_x + a_x
4356	ba_y = - b_y + a_y
4357	ap_x = - a_x + p_x
4358	ap_y = - a_y + p_y
4359	bp_x = - b_x + p_x
4360	bp_y = - b_y + p_y
4361
4362	IF ( ab_x * ap_x + ab_y * ap_y <= 0. ) THEN
4363	dist_point_to_edge = SQRT((a_x - p_x)2 + (a_y - p_y)2)
4364	ELSEIF ( ba_x * bp_x + ba_y * bp_y <= 0. ) THEN
4365	dist_point_to_edge = SQRT((b_x - p_x)2 + (b_y - p_y)2)
4366	ELSE
4367	ab_d = 1./SQRT((ab_x)2+(ab_y)2)
4368	ab_u_x = ab_x*ab_d
4369	ab_u_y = ab_y*ab_d
4370	dist_x = ap_x - (ap_xab_u_x+ap_yab_u_y)*ab_u_x
4371	dist_y = ap_y - (ap_xab_u_x+ap_yab_u_y)*ab_u_y
4372	dist_point_to_edge = SQRT( dist_x2 + dist_y2 )
4373	ENDIF
4374
4375	END FUNCTION dist_point_to_edge
4376
4377	!
4378	!-- Returns the heuristic between points A and B (currently the straight
4379	!-- distance)
4380	FUNCTION heuristic ( ax, ay, bx, by )
4381
4382	IMPLICIT NONE
4383
4384	REAL(wp) :: ax !< x-coordinate of point A
4385	REAL(wp) :: ay !< y-coordinate of point A
4386	REAL(wp) :: bx !< x-coordinate of point B
4387	REAL(wp) :: by !< y-coordinate of point B
4388	REAL(wp) :: heuristic !< return value
4389
4390	heuristic = SQRT(( ax - bx )2 + ( ay - by )2)
4391
4392	END FUNCTION heuristic
4393
4394	!
4395	!-- Calculates if point P is left of the infinite
4396	!-- line that contains A and B (direction: A to B)
4397	!-- Concept: 2D rotation of two vectors
4398	FUNCTION is_left ( ax, ay, bx, by, px, py )
4399
4400	IMPLICIT NONE
4401
4402	LOGICAL :: is_left !< return value; TRUE if P is left of AB
4403
4404	REAL(wp) :: ax !< x-coordinate of point A
4405	REAL(wp) :: ay !< y-coordinate of point A
4406	REAL(wp) :: bx !< x-coordinate of point B
4407	REAL(wp) :: by !< y-coordinate of point B
4408	REAL(wp) :: px !< x-coordinate of point P
4409	REAL(wp) :: py !< y-coordinate of point P
4410
4411	is_left = (bx-ax)(py-ay)-(px-ax)(by-ay) > 0
4412	IF ( (ABS(ax-px) < .001 .AND. ABS(ay-py) < .001) .OR. &
4413	(ABS(bx-px) < .001 .AND. ABS(by-py) < .001) ) &
4414	THEN
4415	is_left = .FALSE.
4416	ENDIF
4417
4418	RETURN
4419
4420	END FUNCTION is_left
4421
4422	!
4423	!-- Calculates if point P is right of the infinite
4424	!-- line that contains A and B (direction: A to B)
4425	!-- Concept: 2D rotation of two vectors
4426	FUNCTION is_right ( ax, ay, bx, by, px, py )
4427
4428	IMPLICIT NONE
4429
4430	LOGICAL :: is_right !< return value; TRUE if P is right of AB
4431
4432	REAL(wp), INTENT(IN) :: ax !< x-coordinate of point A
4433	REAL(wp), INTENT(IN) :: ay !< y-coordinate of point A
4434	REAL(wp), INTENT(IN) :: bx !< x-coordinate of point B
4435	REAL(wp), INTENT(IN) :: by !< y-coordinate of point B
4436	REAL(wp), INTENT(IN) :: px !< x-coordinate of point P
4437	REAL(wp), INTENT(IN) :: py !< y-coordinate of point P
4438
4439	is_right = (bx-ax)(py-ay)-(px-ax)(by-ay) < 0
4440	IF ( (ABS(ax-px) < .001 .AND. ABS(ay-py) < .001) .OR. &
4441	(ABS(bx-px) < .001 .AND. ABS(by-py) < .001) ) &
4442	THEN
4443	is_right = .FALSE.
4444	ENDIF
4445
4446	RETURN
4447
4448	END FUNCTION is_right
4449
4450	!
4451	!-- Returns true if the line segments AB and PQ share an intersection
4452	FUNCTION intersect ( ax, ay, bx, by, px, py, qx, qy )
4453
4454	IMPLICIT NONE
4455
4456	LOGICAL :: intersect !< return value; TRUE if intersection was found
4457	LOGICAL :: la !< T if a is left of PQ
4458	LOGICAL :: lb !< T if b is left of PQ
4459	LOGICAL :: lp !< T if p is left of AB
4460	LOGICAL :: lq !< T if q is left of AB
4461	LOGICAL :: poss !< flag that indicates if an intersection is still possible
4462	LOGICAL :: ra !< T if a is right of PQ
4463	LOGICAL :: rb !< T if b is right of PQ
4464	LOGICAL :: rp !< T if p is right of AB
4465	LOGICAL :: rq !< T if q is right of AB
4466
4467	REAL(wp) :: ax !< x-coordinate of point A
4468	REAL(wp) :: ay !< y-coordinate of point A
4469	REAL(wp) :: bx !< x-coordinate of point B
4470	REAL(wp) :: by !< y-coordinate of point B
4471	REAL(wp) :: px !< x-coordinate of point P
4472	REAL(wp) :: py !< y-coordinate of point P
4473	REAL(wp) :: qx !< x-coordinate of point Q
4474	REAL(wp) :: qy !< y-coordinate of point Q
4475
4476	intersect = .FALSE.
4477	poss = .FALSE.
4478	!
4479	!-- Intersection is possible only if P and Q are on opposing sides of AB
4480	lp = is_left(ax,ay,bx,by,px,py)
4481	rq = is_right(ax,ay,bx,by,qx,qy)
4482	IF ( lp .AND. rq ) poss = .TRUE.
4483	IF ( .NOT. poss ) THEN
4484	lq = is_left(ax,ay,bx,by,qx,qy)
4485	rp = is_right(ax,ay,bx,by,px,py)
4486	IF ( lq .AND. rp ) poss = .TRUE.
4487	ENDIF
4488	!
4489	!-- Intersection occurs only if above test (poss) was true AND
4490	!-- A and B are on opposing sides of PQ
4491	IF ( poss ) THEN
4492	la = is_left(px,py,qx,qy,ax,ay)
4493	rb = is_right(px,py,qx,qy,bx,by)
4494	IF ( la .AND. rb ) intersect = .TRUE.
4495	IF ( .NOT. intersect ) THEN
4496	lb = is_left(px,py,qx,qy,bx,by)
4497	ra = is_right(px,py,qx,qy,ax,ay)
4498	IF ( lb .AND. ra ) intersect = .TRUE.
4499	ENDIF
4500	ENDIF
4501
4502	RETURN
4503
4504	END FUNCTION intersect
4505
4506	!
4507	!-- Gives a nuber randomly distributed around an average
4508	FUNCTION random_normal ( avg, variation )
4509
4510	IMPLICIT NONE
4511
4512	REAL(wp) :: avg !< x-coordinate of vector from A to B
4513	REAL(wp) :: variation !< y-coordinate of vector from A to B
4514	REAL(wp) :: random_normal !< y-coordinate of vector from A to B
4515
4516	REAL(wp), DIMENSION(12) :: random_arr !< inverse length of vector from A to B
4517
4518	CALL RANDOM_NUMBER(random_arr)
4519	random_normal = avg + variation*(SUM(random_arr)-6.)
4520
4521	END FUNCTION random_normal
4522
4523
4524	END MODULE multi_agent_system_mod

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