source: palm/trunk/SOURCE/init_pegrid.f90 @ 3761

Last change on this file since 3761 was 3761, checked in by raasch, 3 years ago

unused variables removed, OpenACC directives re-formatted, statements added to avoid compiler warnings

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1!> @file init_pegrid.f90
2!------------------------------------------------------------------------------!
3! This file is part of the PALM model system.
4!
5! PALM 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 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 1997-2019 Leibniz Universitaet Hannover
18!------------------------------------------------------------------------------!
19!
20! Current revisions:
21! ------------------
22!
23!
24! Former revisions:
25! -----------------
26! $Id: init_pegrid.f90 3761 2019-02-25 15:31:42Z raasch $
27! unused variable removed
28!
29! 3655 2019-01-07 16:51:22Z knoop
30! variables documented
31!
32! 3552 2018-11-22 10:28:35Z suehring
33! Introduce new MPI-datatype for ghostpoint exchange of 2D 8-bit Integer arrays
34!
35! 3542 2018-11-20 17:04:13Z suehring
36! Bugfix in setting number of ghost layers in neutral case
37!
38! 3341 2018-10-15 10:31:27Z suehring
39! unused variables removed
40!
41! 3183 2018-07-27 14:25:55Z suehring
42! Rename variables and boundary conditions in mesoscale-offline nesting mode
43!
44! 3182 2018-07-27 13:36:03Z suehring
45! bugfix: wrong error number in r3057 revised
46!
47! 3057 2018-06-05 09:03:41Z raasch
48! bugfix: check that nz is even in case that optimized multigrid is used
49!
50! 3049 2018-05-29 13:52:36Z Giersch
51! Error messages revised
52!
53! 3045 2018-05-28 07:55:41Z Giersch
54! Error messages revised
55!
56! 2938 2018-03-27 15:52:42Z suehring
57! - No checks for domain decomposition in case of turbulence generator
58!  (is done in stg module)
59! - Introduce ids to indicate lateral processors for turbulence generator
60!
61! 2936 2018-03-27 14:49:27Z suehring
62! Variable use_synthetic_turbulence_generator has been abbreviated
63!
64! 2718 2018-01-02 08:49:38Z maronga
65! Corrected "Former revisions" section
66!
67! 2696 2017-12-14 17:12:51Z kanani
68! Change in file header (GPL part)
69! 3D-Integer exchange on multigrid level (MS)
70! Forcing implemented (MS)
71!
72! 2600 2017-11-01 14:11:20Z raasch
73! calculation of block-I/O quantitites removed (is now done in parin)
74!
75! 2516 2017-10-04 11:03:04Z suehring
76! Remove tabs
77!
78! 2514 2017-10-04 09:52:37Z suehring
79! Redundant preprocessor directives removed
80!
81! 2372 2017-08-25 12:37:32Z sward
82! Shifted cyclic boundary conditions implemented
83!
84! 2365 2017-08-21 14:59:59Z kanani
85! Vertical nesting implemented (SadiqHuq)
86!
87! 2300 2017-06-29 13:31:14Z raasch
88! host-specific settings removed
89!
90! 2298 2017-06-29 09:28:18Z raasch
91! MPI2 related parts removed
92!
93! 2271 2017-06-09 12:34:55Z sward
94! Error message changed
95!
96! 2259 2017-06-08 09:09:11Z gronemeier
97! Implemented synthetic turbulence generator
98!
99! 2238 2017-05-31 16:49:16Z suehring
100! Remove unnecessary module load of pmc_interface
101!
102! 2231 2017-05-30 16:44:33Z suehring
103!
104! 2200 2017-04-11 11:37:51Z suehring
105! monotonic_adjustment removed
106!
107! 2197 2017-03-24 02:25:00Z raasch
108! bugfix: do not allow odd values for nz at the coarsest grid level in case of
109! optimized multigrid solver
110!
111! 2180 2017-03-17 13:33:05Z hellstea
112! Checks to ensure (2178) that pdims match the grid dimensions in the
113! automatic determination of pdims are canceled as unnecessary
114!
115! 2178 2017-03-17 11:07:39Z hellstea
116! Checks to ensure that pdims match the grid dimensions are added in the
117! automatic determination of pdims
118!
119! 2050 2016-11-08 15:00:55Z gronemeier
120! Implement turbulent outflow condition
121!
122! 2000 2016-08-20 18:09:15Z knoop
123! Forced header and separation lines into 80 columns
124!
125! 1968 2016-07-18 12:01:49Z suehring
126! Extent MPI-datatypes for exchange of 2D-INTEGER arrays on coarser multigrid
127! level 
128!
129! 1964 2016-07-14 15:35:18Z hellstea
130! Bugfix: erroneous setting of nest_bound_l/r/s/n = .TRUE. for vertical nesting mode removed.
131!
132! 1923 2016-05-31 16:37:07Z boeske
133! Initial version of purely vertical nesting introduced.
134!
135! 1922 2016-05-31 16:36:08Z boeske
136! Bugfix: array transposition checks restricted to cases if a fourier
137! transform is used , removed unused variable nnx_z
138!
139! 1833 2016-04-07 14:23:03Z raasch
140! spectra related variables moved to spectra_mod
141!
142! 1815 2016-04-06 13:49:59Z raasch
143! cpp-directives for intel openmp bug removed
144!
145! 1804 2016-04-05 16:30:18Z maronga
146! Removed code for parameter file check (__check)
147!
148! 1779 2016-03-03 08:01:28Z raasch
149! changes regarding nested domain removed: virtual PE grid will be automatically
150! calculated for nested runs too
151!
152! 1764 2016-02-28 12:45:19Z raasch
153! cpp-statements for nesting removed
154!
155! 1762 2016-02-25 12:31:13Z hellstea
156! Introduction of nested domain feature
157!
158! 1682 2015-10-07 23:56:08Z knoop
159! Code annotations made doxygen readable
160!
161! 1677 2015-10-02 13:25:23Z boeske
162! New MPI-data types for exchange of 3D integer arrays.
163!
164! 1575 2015-03-27 09:56:27Z raasch
165! adjustments for psolver-queries, calculation of ngp_xz added
166!
167! 1565 2015-03-09 20:59:31Z suehring
168! Refine if-clause for setting nbgp.
169!
170! 1557 2015-03-05 16:43:04Z suehring
171! Adjustment for monotonic limiter
172!
173! 1468 2014-09-24 14:06:57Z maronga
174! Adapted for use on up to 6-digit processor cores
175!
176! 1435 2014-07-21 10:37:02Z keck
177! bugfix: added missing parameter coupling_mode_remote to ONLY-attribute
178!
179! 1402 2014-05-09 14:25:13Z raasch
180! location messages modified
181!
182! 1384 2014-05-02 14:31:06Z raasch
183! location messages added
184!
185! 1353 2014-04-08 15:21:23Z heinze
186! REAL constants provided with KIND-attribute
187!
188! 1322 2014-03-20 16:38:49Z raasch
189! REAL functions provided with KIND-attribute
190!
191! 1320 2014-03-20 08:40:49Z raasch
192! ONLY-attribute added to USE-statements,
193! kind-parameters added to all INTEGER and REAL declaration statements,
194! kinds are defined in new module kinds,
195! revision history before 2012 removed,
196! comment fields (!:) to be used for variable explanations added to
197! all variable declaration statements
198!
199! 1304 2014-03-12 10:29:42Z raasch
200! bugfix: single core MPI runs missed some settings of transpose indices
201!
202! 1212 2013-08-15 08:46:27Z raasch
203! error message for poisfft_hybrid removed
204!
205! 1159 2013-05-21 11:58:22Z fricke
206! dirichlet/neumann and neumann/dirichlet removed
207!
208! 1139 2013-04-18 07:25:03Z raasch
209! bugfix for calculating the id of the PE carrying the recycling plane
210!
211! 1111 2013-03-08 23:54:10Z raasch
212! initialization of poisfft moved to module poisfft
213!
214! 1092 2013-02-02 11:24:22Z raasch
215! unused variables removed
216!
217! 1056 2012-11-16 15:28:04Z raasch
218! Indices for arrays n.._mg start from zero due to definition of arrays f2 and
219! p2 as automatic arrays in recursive subroutine next_mg_level
220!
221! 1041 2012-11-06 02:36:29Z raasch
222! a 2d virtual processor topology is used by default for all machines
223!
224! 1036 2012-10-22 13:43:42Z raasch
225! code put under GPL (PALM 3.9)
226!
227! 1003 2012-09-14 14:35:53Z raasch
228! subdomains must have identical size (grid matching = "match" removed)
229!
230! 1001 2012-09-13 14:08:46Z raasch
231! all actions concerning upstream-spline-method removed
232!
233! 978 2012-08-09 08:28:32Z fricke
234! dirichlet/neumann and neumann/dirichlet added
235! nxlu and nysv are also calculated for inflow boundary
236!
237! 809 2012-01-30 13:32:58Z maronga
238! Bugfix: replaced .AND. and .NOT. with && and ! in the preprocessor directives
239!
240! 807 2012-01-25 11:53:51Z maronga
241! New cpp directive "__check" implemented which is used by check_namelist_files
242!
243! Revision 1.1  1997/07/24 11:15:09  raasch
244! Initial revision
245!
246!
247! Description:
248! ------------
249!> Determination of the virtual processor topology (if not prescribed by the
250!> user)and computation of the grid point number and array bounds of the local
251!> domains.
252!> @todo: remove MPI-data types for 2D exchange on coarse multigrid level (not
253!>        used any more)
254!------------------------------------------------------------------------------!
255 SUBROUTINE init_pegrid
256 
257
258    USE control_parameters,                                                    &
259        ONLY:  bc_dirichlet_l, bc_dirichlet_n, bc_dirichlet_r, bc_dirichlet_s, &
260               bc_lr, bc_ns, bc_radiation_l, bc_radiation_n, bc_radiation_r,   &
261               bc_radiation_s, coupling_mode, coupling_topology, gathered_size,&
262               grid_level, grid_level_count, maximum_grid_level,               &
263               message_string, mg_switch_to_pe0_level, momentum_advec,         &
264               psolver, outflow_source_plane, recycling_width, scalar_advec,   &
265               subdomain_size, turbulent_outflow, y_shift
266
267    USE grid_variables,                                                        &
268        ONLY:  dx
269       
270    USE indices,                                                               &
271        ONLY:  mg_loc_ind, nbgp, nnx, nny, nnz, nx, nx_a, nx_o, nxl, nxl_mg,   &
272               nxlu, nxr, nxr_mg, ny, ny_a, ny_o, nyn, nyn_mg, nys, nys_mg,    &
273               nysv, nz, nzb, nzt, nzt_mg, wall_flags_1, wall_flags_2,         &
274               wall_flags_3, wall_flags_4, wall_flags_5, wall_flags_6,         &
275               wall_flags_7, wall_flags_8, wall_flags_9, wall_flags_10
276
277    USE kinds
278     
279    USE pegrid
280     
281    USE spectra_mod,                                                           &
282        ONLY:  calculate_spectra, dt_dosp
283
284    USE synthetic_turbulence_generator_mod,                                    &
285        ONLY:  id_stg_left, id_stg_north, id_stg_right, id_stg_south,          &
286               use_syn_turb_gen
287
288    USE transpose_indices,                                                     &
289        ONLY:  nxl_y, nxl_yd, nxl_z, nxr_y, nxr_yd, nxr_z, nyn_x, nyn_z, nys_x,&
290               nys_z, nzb_x, nzb_y, nzb_yd, nzt_x, nzt_yd, nzt_y
291
292    USE vertical_nesting_mod,                                                  &
293        ONLY:  vnested, vnest_init_pegrid_domain, vnest_init_pegrid_rank
294
295    IMPLICIT NONE
296
297    INTEGER(iwp) ::  i                        !< running index over number of processors or number of multigrid level
298    INTEGER(iwp) ::  id_inflow_l              !< ID indicating processors located at the left inflow boundary
299    INTEGER(iwp) ::  id_outflow_l             !< local value of id_outflow
300    INTEGER(iwp) ::  id_outflow_source_l      !< local value of id_outflow_source
301    INTEGER(iwp) ::  id_recycling_l           !< ID indicating processors located at the recycling plane
302    INTEGER(iwp) ::  id_stg_left_l            !< left lateral boundary local core id in case of turbulence generator 
303    INTEGER(iwp) ::  id_stg_north_l           !< north lateral boundary local core id in case of turbulence generator 
304    INTEGER(iwp) ::  id_stg_right_l           !< right lateral boundary local core id in case of turbulence generator 
305    INTEGER(iwp) ::  id_stg_south_l           !< south lateral boundary local core id in case of turbulence generator 
306    INTEGER(iwp) ::  ind(5)                   !< array containing the subdomain bounds
307    INTEGER(iwp) ::  j                        !< running index, used for various loops
308    INTEGER(iwp) ::  k                        !< number of vertical grid points in different multigrid level
309    INTEGER(iwp) ::  maximum_grid_level_l     !< maximum number of grid level without switching to PE 0
310    INTEGER(iwp) ::  mg_levels_x              !< maximum number of grid level allowed along x-direction
311    INTEGER(iwp) ::  mg_levels_y              !< maximum number of grid level allowed along y-direction
312    INTEGER(iwp) ::  mg_levels_z              !< maximum number of grid level allowed along z-direction
313    INTEGER(iwp) ::  mg_switch_to_pe0_level_l !< maximum number of grid level with switching to PE 0
314    INTEGER(iwp) ::  nnx_y                    !< quotient of number of grid points along x-direction and number of PEs used along y-direction
315    INTEGER(iwp) ::  nny_x                    !< quotient of number of grid points along y-direction and number of PEs used along x-direction
316    INTEGER(iwp) ::  nny_z                    !< quotient of number of grid points along y-direction and number of PEs used along x-direction
317    INTEGER(iwp) ::  nnz_x                    !< quotient of number of grid points along z-direction and number of PEs used along x-direction
318    INTEGER(iwp) ::  nnz_y                    !< quotient of number of grid points along z-direction and number of PEs used along x-direction
319    INTEGER(iwp) ::  numproc_sqr              !< square root of the number of processors
320    INTEGER(iwp) ::  nxl_l                    !< lower index bound along x-direction on subdomain and different multigrid level
321    INTEGER(iwp) ::  nxr_l                    !< upper index bound along x-direction on subdomain and different multigrid level
322    INTEGER(iwp) ::  nyn_l                    !< lower index bound along y-direction on subdomain and different multigrid level
323    INTEGER(iwp) ::  nys_l                    !< upper index bound along y-direction on subdomain and different multigrid level
324    INTEGER(iwp) ::  nzb_l                    !< lower index bound along z-direction on subdomain and different multigrid level
325    INTEGER(iwp) ::  nzt_l                    !< upper index bound along z-direction on subdomain and different multigrid level
326!$  INTEGER(iwp) ::  omp_get_num_threads      !< number of OpenMP threads
327
328    INTEGER(iwp), DIMENSION(:), ALLOCATABLE ::  ind_all !< dummy array containing index bounds on subdomain, used for gathering
329    INTEGER(iwp), DIMENSION(:), ALLOCATABLE ::  nxlf    !< lower index bound allong x-direction for every PE
330    INTEGER(iwp), DIMENSION(:), ALLOCATABLE ::  nxrf    !< upper index bound allong x-direction for every PE
331    INTEGER(iwp), DIMENSION(:), ALLOCATABLE ::  nynf    !< lower index bound allong y-direction for every PE
332    INTEGER(iwp), DIMENSION(:), ALLOCATABLE ::  nysf    !< lower index bound allong y-direction for every PE
333
334    INTEGER(iwp), DIMENSION(2) ::  pdims_remote         !< number of PEs used for coupled model (only in atmospher-ocean coupling)
335    INTEGER(iwp)               ::  lcoord(2)            !< PE coordinates of left neighbor along x and y
336    INTEGER(iwp)               ::  rcoord(2)            !< PE coordinates of right neighbor along x and y
337
338!
339!-- Get the number of OpenMP threads
340    !$OMP PARALLEL
341!$  threads_per_task = omp_get_num_threads()
342    !$OMP END PARALLEL
343
344
345#if defined( __parallel )
346
347    CALL location_message( 'creating virtual PE grids + MPI derived data types', &
348                           .FALSE. )
349
350!
351!-- Determine the processor topology or check it, if prescribed by the user
352    IF ( npex == -1  .AND.  npey == -1 )  THEN
353
354!
355!--    Automatic determination of the topology
356       numproc_sqr = SQRT( REAL( numprocs, KIND=wp ) )
357       pdims(1)    = MAX( numproc_sqr , 1 )
358       DO  WHILE ( MOD( numprocs , pdims(1) ) /= 0 )
359          pdims(1) = pdims(1) - 1
360       ENDDO
361       pdims(2) = numprocs / pdims(1)
362
363    ELSEIF ( npex /= -1  .AND.  npey /= -1 )  THEN
364
365!
366!--    Prescribed by user. Number of processors on the prescribed topology
367!--    must be equal to the number of PEs available to the job
368       IF ( ( npex * npey ) /= numprocs )  THEN
369          WRITE( message_string, * ) 'number of PEs of the prescribed ',       &
370              'topology (', npex*npey,') does not match & the number of ',     &
371              'PEs available to the job (', numprocs, ')'
372          CALL message( 'init_pegrid', 'PA0221', 1, 2, 0, 6, 0 )
373       ENDIF
374       pdims(1) = npex
375       pdims(2) = npey
376
377    ELSE
378!
379!--    If the processor topology is prescribed by the user, the number of
380!--    PEs must be given in both directions
381       message_string = 'if the processor topology is prescribed by th' //     &
382                'e user & both values of "npex" and "npey" must be given' //   &
383                ' in the &NAMELIST-parameter file'
384       CALL message( 'init_pegrid', 'PA0222', 1, 2, 0, 6, 0 )
385
386    ENDIF
387
388!
389!-- If necessary, set horizontal boundary conditions to non-cyclic
390    IF ( bc_lr /= 'cyclic' )  cyclic(1) = .FALSE.
391    IF ( bc_ns /= 'cyclic' )  cyclic(2) = .FALSE.
392
393
394!
395!-- Create the virtual processor grid
396    CALL MPI_CART_CREATE( comm_palm, ndim, pdims, cyclic, reorder, &
397                          comm2d, ierr )
398    CALL MPI_COMM_RANK( comm2d, myid, ierr )
399    WRITE (myid_char,'(''_'',I6.6)')  myid
400
401    CALL MPI_CART_COORDS( comm2d, myid, ndim, pcoord, ierr )
402    CALL MPI_CART_SHIFT( comm2d, 0, 1, pleft, pright, ierr )
403    CALL MPI_CART_SHIFT( comm2d, 1, 1, psouth, pnorth, ierr )
404!
405!-- In case of cyclic boundary conditions, a y-shift at the boundaries in
406!-- x-direction can be introduced via parameter y_shift. The shift is done
407!-- by modifying the processor grid in such a way that processors located
408!-- at the x-boundary communicate across it to processors with y-coordinate
409!-- shifted by y_shift relative to their own. This feature can not be used
410!-- in combination with an fft pressure solver. It has been implemented to
411!-- counter the effect of streak structures in case of cyclic boundary
412!-- conditions. For a description of these see Munters
413!-- (2016; dx.doi.org/10.1063/1.4941912)
414!--
415!-- Get coordinates of left and right neighbor on PE grid
416    IF ( y_shift /= 0 ) THEN
417
418       IF ( bc_lr /= 'cyclic'  .OR.  bc_ns /= 'cyclic' )  THEN
419          message_string = 'y_shift /= 0 is only allowed for cyclic ' //       &
420                           'boundary conditions in both directions '
421          CALL message( 'check_parameters', 'PA0467', 1, 2, 0, 6, 0 )
422       ENDIF
423       IF ( TRIM( psolver ) /= 'multigrid' .AND.                               &
424            TRIM( psolver ) /= 'multigrid_noopt')                              &
425       THEN
426          message_string = 'y_shift /= 0 requires a multigrid pressure solver '
427          CALL message( 'check_parameters', 'PA0468', 1, 2, 0, 6, 0 )
428       ENDIF
429
430       CALL MPI_CART_COORDS( comm2d, pright, ndim, rcoord, ierr )
431       CALL MPI_CART_COORDS( comm2d, pleft, ndim, lcoord, ierr )
432
433!
434!--    If the x(y)-coordinate of the right (left) neighbor is smaller (greater)
435!--    than that of the calling process, then the calling process is located on
436!--    the right (left) boundary of the processor grid. In that case,
437!--    the y-coordinate of that neighbor is increased (decreased) by y_shift.
438!--    The rank of the process with that coordinate is then inquired and the
439!--    neighbor rank for MPI_SENDRECV, pright (pleft) is set to it.
440!--    In this way, the calling process receives a new right (left) neighbor
441!--    for all future MPI_SENDRECV calls. That neighbor has a y-coordinate
442!--    of y+(-)y_shift, where y is the original right (left) neighbor's
443!--    y-coordinate. The modulo-operation ensures that if the neighbor's
444!--    y-coordinate exceeds the grid-boundary, it will be relocated to
445!--    the opposite part of the grid cyclicly.
446       IF ( rcoord(1) < pcoord(1) ) THEN
447          rcoord(2) = MODULO( rcoord(2) + y_shift, pdims(2) )
448          CALL MPI_CART_RANK( comm2d, rcoord, pright, ierr )
449       ENDIF
450
451       IF ( lcoord(1) > pcoord(1) ) THEN
452          lcoord(2) = MODULO( lcoord(2) - y_shift, pdims(2) )
453          CALL MPI_CART_RANK( comm2d, lcoord, pleft, ierr )
454       ENDIF
455    ENDIF
456!
457!-- Vertical nesting: store four lists that identify partner ranks to exchange
458!-- data
459    IF ( vnested )  CALL vnest_init_pegrid_rank
460
461!
462!-- Determine sub-topologies for transpositions
463!-- Transposition from z to x:
464    remain_dims(1) = .TRUE.
465    remain_dims(2) = .FALSE.
466    CALL MPI_CART_SUB( comm2d, remain_dims, comm1dx, ierr )
467    CALL MPI_COMM_RANK( comm1dx, myidx, ierr )
468!
469!-- Transposition from x to y
470    remain_dims(1) = .FALSE.
471    remain_dims(2) = .TRUE.
472    CALL MPI_CART_SUB( comm2d, remain_dims, comm1dy, ierr )
473    CALL MPI_COMM_RANK( comm1dy, myidy, ierr )
474
475
476!
477!-- Calculate array bounds along x-direction for every PE.
478    ALLOCATE( nxlf(0:pdims(1)-1), nxrf(0:pdims(1)-1), nynf(0:pdims(2)-1),      &
479              nysf(0:pdims(2)-1) )
480
481    IF ( MOD( nx+1 , pdims(1) ) /= 0 )  THEN
482       WRITE( message_string, * ) 'x-direction: gridpoint number (',nx+1,') ', &
483                               'is not an& integral divisor of the number ',    &
484                               'of processors (', pdims(1),')'
485       CALL message( 'init_pegrid', 'PA0225', 1, 2, 0, 6, 0 )
486    ELSE
487       nnx  = ( nx + 1 ) / pdims(1)
488    ENDIF   
489
490!
491!-- Left and right array bounds, number of gridpoints
492    DO  i = 0, pdims(1)-1
493       nxlf(i)   = i * nnx
494       nxrf(i)   = ( i + 1 ) * nnx - 1
495    ENDDO
496
497!
498!-- Calculate array bounds in y-direction for every PE.
499    IF ( MOD( ny+1 , pdims(2) ) /= 0 )  THEN
500       WRITE( message_string, * ) 'y-direction: gridpoint number (',ny+1,') ', &
501                           'is not an& integral divisor of the number of',      &
502                           'processors (', pdims(2),')'
503       CALL message( 'init_pegrid', 'PA0227', 1, 2, 0, 6, 0 )
504    ELSE
505       nny  = ( ny + 1 ) / pdims(2)
506    ENDIF   
507
508!
509!-- South and north array bounds
510    DO  j = 0, pdims(2)-1
511       nysf(j)   = j * nny
512       nynf(j)   = ( j + 1 ) * nny - 1
513    ENDDO
514
515!
516!-- Local array bounds of the respective PEs
517    nxl = nxlf(pcoord(1))
518    nxr = nxrf(pcoord(1))
519    nys = nysf(pcoord(2))
520    nyn = nynf(pcoord(2))
521    nzb = 0
522    nzt = nz
523    nnz = nz
524
525!
526!-- Set switches to define if the PE is situated at the border of the virtual
527!-- processor grid
528    IF ( nxl == 0 )   left_border_pe  = .TRUE.
529    IF ( nxr == nx )  right_border_pe = .TRUE.
530    IF ( nys == 0 )   south_border_pe = .TRUE.
531    IF ( nyn == ny )  north_border_pe = .TRUE.
532
533!
534!-- Calculate array bounds and gridpoint numbers for the transposed arrays
535!-- (needed in the pressure solver)
536!-- For the transposed arrays, cyclic boundaries as well as top and bottom
537!-- boundaries are omitted, because they are obstructive to the transposition
538
539!
540!-- 1. transposition  z --> x
541!-- This transposition is not neccessary in case of a 1d-decomposition along x
542    IF ( psolver == 'poisfft'  .OR.  calculate_spectra )  THEN
543
544       IF ( pdims(2) /= 1 )  THEN
545          IF ( MOD( nz , pdims(1) ) /= 0 )  THEN
546             WRITE( message_string, * ) 'transposition z --> x:',              &
547                       '& nz=',nz,' is not an integral divisior of pdims(1)=', &
548                                                                   pdims(1)
549             CALL message( 'init_pegrid', 'PA0230', 1, 2, 0, 6, 0 )
550          ENDIF
551       ENDIF
552
553       nys_x = nys
554       nyn_x = nyn
555       nny_x = nny
556       nnz_x = nz / pdims(1)
557       nzb_x = 1 + myidx * nnz_x
558       nzt_x = ( myidx + 1 ) * nnz_x
559       sendrecvcount_zx = nnx * nny * nnz_x
560
561    ENDIF
562
563
564    IF ( psolver == 'poisfft' )  THEN 
565!
566!--    2. transposition  x --> y
567       IF ( MOD( nx+1 , pdims(2) ) /= 0 )  THEN
568          WRITE( message_string, * ) 'transposition x --> y:',                 &
569                            '& nx+1=',nx+1,' is not an integral divisor of ',  &
570                            'pdims(2)=',pdims(2)
571          CALL message( 'init_pegrid', 'PA0231', 1, 2, 0, 6, 0 )
572       ENDIF
573
574       nnz_y = nnz_x
575       nzb_y = nzb_x
576       nzt_y = nzt_x
577       nnx_y = (nx+1) / pdims(2)
578       nxl_y = myidy * nnx_y
579       nxr_y = ( myidy + 1 ) * nnx_y - 1
580       sendrecvcount_xy = nnx_y * nny_x * nnz_y
581!
582!--    3. transposition  y --> z 
583!--    (ELSE:  x --> y  in case of 1D-decomposition along x)
584       nxl_z = nxl_y
585       nxr_z = nxr_y
586       nny_z = (ny+1) / pdims(1)
587       nys_z = myidx * nny_z
588       nyn_z = ( myidx + 1 ) * nny_z - 1
589       sendrecvcount_yz = nnx_y * nny_z * nnz_y
590
591       IF ( pdims(2) /= 1 )  THEN
592!
593!--       y --> z
594!--       This transposition is not neccessary in case of a 1d-decomposition
595!--       along x, except that the uptream-spline method is switched on
596          IF ( MOD( ny+1 , pdims(1) ) /= 0 )  THEN
597             WRITE( message_string, * ) 'transposition y --> z:',              &
598                               '& ny+1=',ny+1,' is not an integral divisor of',&
599                               ' pdims(1)=',pdims(1)
600             CALL message( 'init_pegrid', 'PA0232', 1, 2, 0, 6, 0 )
601          ENDIF
602
603       ELSE
604!
605!--       x --> y
606!--       This condition must be fulfilled for a 1D-decomposition along x
607          IF ( MOD( ny+1 , pdims(1) ) /= 0 )  THEN
608             WRITE( message_string, * ) 'transposition x --> y:',              &
609                               '& ny+1=',ny+1,' is not an integral divisor of',&
610                               ' pdims(1)=',pdims(1)
611             CALL message( 'init_pegrid', 'PA0233', 1, 2, 0, 6, 0 )
612          ENDIF
613
614       ENDIF
615
616    ENDIF
617
618!
619!-- Indices for direct transpositions z --> y (used for calculating spectra)
620    IF ( calculate_spectra )  THEN
621       IF ( MOD( nz, pdims(2) ) /= 0 )  THEN
622          WRITE( message_string, * ) 'direct transposition z --> y (needed ',  &
623                    'for spectra): nz=',nz,' is not an integral divisor of ',  &
624                    'pdims(2)=',pdims(2)
625          CALL message( 'init_pegrid', 'PA0234', 1, 2, 0, 6, 0 )
626       ELSE
627          nxl_yd = nxl
628          nxr_yd = nxr
629          nzb_yd = 1 + myidy * ( nz / pdims(2) )
630          nzt_yd = ( myidy + 1 ) * ( nz / pdims(2) )
631          sendrecvcount_zyd = nnx * nny * ( nz / pdims(2) )
632       ENDIF
633    ENDIF
634
635    IF ( psolver == 'poisfft'  .OR.  calculate_spectra )  THEN
636!
637!--    Indices for direct transpositions y --> x
638!--    (they are only possible in case of a 1d-decomposition along x)
639       IF ( pdims(2) == 1 )  THEN
640          nny_x = nny / pdims(1)
641          nys_x = myid * nny_x
642          nyn_x = ( myid + 1 ) * nny_x - 1
643          nzb_x = 1
644          nzt_x = nz
645          sendrecvcount_xy = nnx * nny_x * nz
646       ENDIF
647
648    ENDIF
649
650    IF ( psolver == 'poisfft' )  THEN
651!
652!--    Indices for direct transpositions x --> y
653!--    (they are only possible in case of a 1d-decomposition along y)
654       IF ( pdims(1) == 1 )  THEN
655          nnx_y = nnx / pdims(2)
656          nxl_y = myid * nnx_y
657          nxr_y = ( myid + 1 ) * nnx_y - 1
658          nzb_y = 1
659          nzt_y = nz
660          sendrecvcount_xy = nnx_y * nny * nz
661       ENDIF
662
663    ENDIF
664
665!
666!-- Arrays for storing the array bounds are needed any more
667    DEALLOCATE( nxlf , nxrf , nynf , nysf )
668
669
670!
671!-- Collect index bounds from other PEs (to be written to restart file later)
672    ALLOCATE( hor_index_bounds(4,0:numprocs-1) )
673
674    IF ( myid == 0 )  THEN
675
676       hor_index_bounds(1,0) = nxl
677       hor_index_bounds(2,0) = nxr
678       hor_index_bounds(3,0) = nys
679       hor_index_bounds(4,0) = nyn
680
681!
682!--    Receive data from all other PEs
683       DO  i = 1, numprocs-1
684          CALL MPI_RECV( ibuf, 4, MPI_INTEGER, i, MPI_ANY_TAG, comm2d, status, &
685                         ierr )
686          hor_index_bounds(:,i) = ibuf(1:4)
687       ENDDO
688
689    ELSE
690!
691!--    Send index bounds to PE0
692       ibuf(1) = nxl
693       ibuf(2) = nxr
694       ibuf(3) = nys
695       ibuf(4) = nyn
696       CALL MPI_SEND( ibuf, 4, MPI_INTEGER, 0, myid, comm2d, ierr )
697
698    ENDIF
699
700
701#if defined( __print )
702!
703!-- Control output
704    IF ( myid == 0 )  THEN
705       PRINT*, '*** processor topology ***'
706       PRINT*, ' '
707       PRINT*, 'myid   pcoord    left right  south north  idx idy   nxl: nxr',&
708               &'   nys: nyn'
709       PRINT*, '------------------------------------------------------------',&
710               &'-----------'
711       WRITE (*,1000)  0, pcoord(1), pcoord(2), pleft, pright, psouth, pnorth, &
712                       myidx, myidy, nxl, nxr, nys, nyn
7131000   FORMAT (I4,2X,'(',I3,',',I3,')',3X,I4,2X,I4,3X,I4,2X,I4,2X,I3,1X,I3, &
714               2(2X,I4,':',I4))
715
716!
717!--    Receive data from the other PEs
718       DO  i = 1,numprocs-1
719          CALL MPI_RECV( ibuf, 12, MPI_INTEGER, i, MPI_ANY_TAG, comm2d, status, &
720                         ierr )
721          WRITE (*,1000)  i, ( ibuf(j) , j = 1,12 )
722       ENDDO
723    ELSE
724
725!
726!--    Send data to PE0
727       ibuf(1) = pcoord(1); ibuf(2) = pcoord(2); ibuf(3) = pleft
728       ibuf(4) = pright; ibuf(5) = psouth; ibuf(6) = pnorth; ibuf(7) = myidx
729       ibuf(8) = myidy; ibuf(9) = nxl; ibuf(10) = nxr; ibuf(11) = nys
730       ibuf(12) = nyn
731       CALL MPI_SEND( ibuf, 12, MPI_INTEGER, 0, myid, comm2d, ierr )       
732    ENDIF
733#endif
734
735!
736!-- Determine the number of ghost point layers
737    IF ( scalar_advec   == 'ws-scheme'  .OR.                                   &
738         momentum_advec == 'ws-scheme' )  THEN
739       nbgp = 3
740    ELSE
741       nbgp = 1
742    ENDIF
743
744!
745!-- Create a new MPI derived datatype for the exchange of surface (xy) data,
746!-- which is needed for coupled atmosphere-ocean runs.
747!-- First, calculate number of grid points of an xy-plane.
748    ngp_xy  = ( nxr - nxl + 1 + 2 * nbgp ) * ( nyn - nys + 1 + 2 * nbgp )
749    CALL MPI_TYPE_VECTOR( ngp_xy, 1, nzt-nzb+2, MPI_REAL, type_xy, ierr )
750    CALL MPI_TYPE_COMMIT( type_xy, ierr )
751
752    IF ( TRIM( coupling_mode ) /= 'uncoupled' .AND. .NOT. vnested )  THEN
753   
754!
755!--    Pass the number of grid points of the atmosphere model to
756!--    the ocean model and vice versa
757       IF ( coupling_mode == 'atmosphere_to_ocean' )  THEN
758
759          nx_a = nx
760          ny_a = ny
761
762          IF ( myid == 0 )  THEN
763
764             CALL MPI_SEND( nx_a, 1, MPI_INTEGER, numprocs, 1, comm_inter,  &
765                            ierr )
766             CALL MPI_SEND( ny_a, 1, MPI_INTEGER, numprocs, 2, comm_inter,  &
767                            ierr )
768             CALL MPI_SEND( pdims, 2, MPI_INTEGER, numprocs, 3, comm_inter, &
769                            ierr )
770             CALL MPI_RECV( nx_o, 1, MPI_INTEGER, numprocs, 4, comm_inter,  &
771                            status, ierr )
772             CALL MPI_RECV( ny_o, 1, MPI_INTEGER, numprocs, 5, comm_inter,  &
773                            status, ierr )
774             CALL MPI_RECV( pdims_remote, 2, MPI_INTEGER, numprocs, 6,      &
775                            comm_inter, status, ierr )
776          ENDIF
777
778          CALL MPI_BCAST( nx_o, 1, MPI_INTEGER, 0, comm2d, ierr )
779          CALL MPI_BCAST( ny_o, 1, MPI_INTEGER, 0, comm2d, ierr ) 
780          CALL MPI_BCAST( pdims_remote, 2, MPI_INTEGER, 0, comm2d, ierr )
781       
782       ELSEIF ( coupling_mode == 'ocean_to_atmosphere' )  THEN
783
784          nx_o = nx
785          ny_o = ny
786
787          IF ( myid == 0 ) THEN
788
789             CALL MPI_RECV( nx_a, 1, MPI_INTEGER, 0, 1, comm_inter, status, &
790                            ierr )
791             CALL MPI_RECV( ny_a, 1, MPI_INTEGER, 0, 2, comm_inter, status, &
792                            ierr )
793             CALL MPI_RECV( pdims_remote, 2, MPI_INTEGER, 0, 3, comm_inter, &
794                            status, ierr )
795             CALL MPI_SEND( nx_o, 1, MPI_INTEGER, 0, 4, comm_inter, ierr )
796             CALL MPI_SEND( ny_o, 1, MPI_INTEGER, 0, 5, comm_inter, ierr )
797             CALL MPI_SEND( pdims, 2, MPI_INTEGER, 0, 6, comm_inter, ierr )
798          ENDIF
799
800          CALL MPI_BCAST( nx_a, 1, MPI_INTEGER, 0, comm2d, ierr)
801          CALL MPI_BCAST( ny_a, 1, MPI_INTEGER, 0, comm2d, ierr) 
802          CALL MPI_BCAST( pdims_remote, 2, MPI_INTEGER, 0, comm2d, ierr) 
803
804       ENDIF
805 
806       ngp_a = ( nx_a+1 + 2 * nbgp ) * ( ny_a+1 + 2 * nbgp )
807       ngp_o = ( nx_o+1 + 2 * nbgp ) * ( ny_o+1 + 2 * nbgp )
808
809!
810!--    Determine if the horizontal grid and the number of PEs in ocean and
811!--    atmosphere is same or not
812       IF ( nx_o == nx_a  .AND.  ny_o == ny_a  .AND.  &
813            pdims(1) == pdims_remote(1) .AND. pdims(2) == pdims_remote(2) ) &
814       THEN
815          coupling_topology = 0
816       ELSE
817          coupling_topology = 1
818       ENDIF
819
820!
821!--    Determine the target PEs for the exchange between ocean and
822!--    atmosphere (comm2d)
823       IF ( coupling_topology == 0 )  THEN
824!
825!--       In case of identical topologies, every atmosphere PE has exactly one
826!--       ocean PE counterpart and vice versa
827          IF ( TRIM( coupling_mode ) == 'atmosphere_to_ocean' ) THEN
828             target_id = myid + numprocs
829          ELSE
830             target_id = myid
831          ENDIF
832
833       ELSE
834!
835!--       In case of nonequivalent topology in ocean and atmosphere only for
836!--       PE0 in ocean and PE0 in atmosphere a target_id is needed, since
837!--       data echxchange between ocean and atmosphere will be done only
838!--       between these PEs.   
839          IF ( myid == 0 )  THEN
840
841             IF ( TRIM( coupling_mode ) == 'atmosphere_to_ocean' )  THEN
842                target_id = numprocs
843             ELSE
844                target_id = 0
845             ENDIF
846
847          ENDIF
848
849       ENDIF
850
851    ENDIF
852
853!
854!-- Store partner grid point co-ordinates as lists.
855!-- Create custom MPI vector datatypes for contiguous data transfer
856    IF ( vnested )  CALL vnest_init_pegrid_domain
857
858#else
859
860!
861!-- Array bounds when running on a single PE (respectively a non-parallel
862!-- machine)
863    nxl = 0
864    nxr = nx
865    nnx = nxr - nxl + 1
866    nys = 0
867    nyn = ny
868    nny = nyn - nys + 1
869    nzb = 0
870    nzt = nz
871    nnz = nz
872
873    ALLOCATE( hor_index_bounds(4,0:0) )
874    hor_index_bounds(1,0) = nxl
875    hor_index_bounds(2,0) = nxr
876    hor_index_bounds(3,0) = nys
877    hor_index_bounds(4,0) = nyn
878
879!
880!-- Array bounds for the pressure solver (in the parallel code, these bounds
881!-- are the ones for the transposed arrays)
882    nys_x = nys
883    nyn_x = nyn
884    nzb_x = nzb + 1
885    nzt_x = nzt
886
887    nxl_y = nxl
888    nxr_y = nxr
889    nzb_y = nzb + 1
890    nzt_y = nzt
891
892    nxl_z = nxl
893    nxr_z = nxr
894    nys_z = nys
895    nyn_z = nyn
896
897#endif
898
899!
900!-- Calculate number of grid levels necessary for the multigrid poisson solver
901!-- as well as the gridpoint indices on each level
902    IF ( psolver(1:9) == 'multigrid' )  THEN
903
904!
905!--    First calculate number of possible grid levels for the subdomains
906       mg_levels_x = 1
907       mg_levels_y = 1
908       mg_levels_z = 1
909
910       i = nnx
911       DO WHILE ( MOD( i, 2 ) == 0  .AND.  i /= 2 )
912          i = i / 2
913          mg_levels_x = mg_levels_x + 1
914       ENDDO
915
916       j = nny
917       DO WHILE ( MOD( j, 2 ) == 0  .AND.  j /= 2 )
918          j = j / 2
919          mg_levels_y = mg_levels_y + 1
920       ENDDO
921
922       k = nz    ! do not use nnz because it might be > nz due to transposition
923                 ! requirements
924       DO WHILE ( MOD( k, 2 ) == 0  .AND.  k /= 2 )
925          k = k / 2
926          mg_levels_z = mg_levels_z + 1
927       ENDDO
928!
929!--    The optimized MG-solver does not allow odd values for nz at the coarsest
930!--    grid level
931       IF ( TRIM( psolver ) /= 'multigrid_noopt' )  THEN
932          IF ( MOD( k, 2 ) /= 0 )  mg_levels_z = mg_levels_z - 1
933!
934!--       An odd value of nz does not work. The finest level must have an even
935!--       value.
936          IF (  mg_levels_z == 0 )  THEN
937             message_string = 'optimized multigrid method requires nz to be even'
938             CALL message( 'init_pegrid', 'PA0495', 1, 2, 0, 6, 0 )
939          ENDIF
940       ENDIF
941
942       maximum_grid_level = MIN( mg_levels_x, mg_levels_y, mg_levels_z )
943
944!
945!--    Find out, if the total domain allows more levels. These additional
946!--    levels are identically processed on all PEs.
947       IF ( numprocs > 1  .AND.  mg_switch_to_pe0_level /= -1 )  THEN
948
949          IF ( mg_levels_z > MIN( mg_levels_x, mg_levels_y ) )  THEN
950
951             mg_switch_to_pe0_level_l = maximum_grid_level
952
953             mg_levels_x = 1
954             mg_levels_y = 1
955
956             i = nx+1
957             DO WHILE ( MOD( i, 2 ) == 0  .AND.  i /= 2 )
958                i = i / 2
959                mg_levels_x = mg_levels_x + 1
960             ENDDO
961
962             j = ny+1
963             DO WHILE ( MOD( j, 2 ) == 0  .AND.  j /= 2 )
964                j = j / 2
965                mg_levels_y = mg_levels_y + 1
966             ENDDO
967
968             maximum_grid_level_l = MIN( mg_levels_x, mg_levels_y, mg_levels_z )
969
970             IF ( maximum_grid_level_l > mg_switch_to_pe0_level_l )  THEN
971                mg_switch_to_pe0_level_l = maximum_grid_level_l - &
972                                           mg_switch_to_pe0_level_l + 1
973             ELSE
974                mg_switch_to_pe0_level_l = 0
975             ENDIF
976
977          ELSE
978
979             mg_switch_to_pe0_level_l = 0
980             maximum_grid_level_l = maximum_grid_level
981
982          ENDIF
983
984!
985!--       Use switch level calculated above only if it is not pre-defined
986!--       by user
987          IF ( mg_switch_to_pe0_level == 0 )  THEN
988             IF ( mg_switch_to_pe0_level_l /= 0 )  THEN
989                mg_switch_to_pe0_level = mg_switch_to_pe0_level_l
990                maximum_grid_level     = maximum_grid_level_l
991             ENDIF
992
993          ELSE
994!
995!--          Check pre-defined value and reset to default, if neccessary
996             IF ( mg_switch_to_pe0_level < mg_switch_to_pe0_level_l  .OR.      &
997                  mg_switch_to_pe0_level >= maximum_grid_level_l )  THEN
998                message_string = 'mg_switch_to_pe0_level ' //                  &
999                                 'out of range and reset to 0'
1000                CALL message( 'init_pegrid', 'PA0235', 0, 1, 0, 6, 0 )
1001                mg_switch_to_pe0_level = 0
1002             ELSE
1003!
1004!--             Use the largest number of possible levels anyway and recalculate
1005!--             the switch level to this largest number of possible values
1006                maximum_grid_level = maximum_grid_level_l
1007
1008             ENDIF
1009
1010          ENDIF
1011
1012       ENDIF
1013
1014       ALLOCATE( grid_level_count(maximum_grid_level),                       &
1015                 nxl_mg(0:maximum_grid_level), nxr_mg(0:maximum_grid_level), &
1016                 nyn_mg(0:maximum_grid_level), nys_mg(0:maximum_grid_level), &
1017                 nzt_mg(0:maximum_grid_level) )
1018
1019       grid_level_count = 0
1020!
1021!--    Index zero required as dummy due to definition of arrays f2 and p2 in
1022!--    recursive subroutine next_mg_level
1023       nxl_mg(0) = 0; nxr_mg(0) = 0; nyn_mg(0) = 0; nys_mg(0) = 0; nzt_mg(0) = 0
1024
1025       nxl_l = nxl; nxr_l = nxr; nys_l = nys; nyn_l = nyn; nzt_l = nzt
1026
1027       DO  i = maximum_grid_level, 1 , -1
1028
1029          IF ( i == mg_switch_to_pe0_level )  THEN
1030#if defined( __parallel )
1031!
1032!--          Save the grid size of the subdomain at the switch level, because
1033!--          it is needed in poismg.
1034             ind(1) = nxl_l; ind(2) = nxr_l
1035             ind(3) = nys_l; ind(4) = nyn_l
1036             ind(5) = nzt_l
1037             ALLOCATE( ind_all(5*numprocs), mg_loc_ind(5,0:numprocs-1) )
1038             CALL MPI_ALLGATHER( ind, 5, MPI_INTEGER, ind_all, 5, &
1039                                 MPI_INTEGER, comm2d, ierr )
1040             DO  j = 0, numprocs-1
1041                DO  k = 1, 5
1042                   mg_loc_ind(k,j) = ind_all(k+j*5)
1043                ENDDO
1044             ENDDO
1045             DEALLOCATE( ind_all )
1046!
1047!--          Calculate the grid size of the total domain
1048             nxr_l = ( nxr_l-nxl_l+1 ) * pdims(1) - 1
1049             nxl_l = 0
1050             nyn_l = ( nyn_l-nys_l+1 ) * pdims(2) - 1
1051             nys_l = 0
1052!
1053!--          The size of this gathered array must not be larger than the
1054!--          array tend, which is used in the multigrid scheme as a temporary
1055!--          array. Therefore the subdomain size of an PE is calculated and
1056!--          the size of the gathered grid. These values are used in 
1057!--          routines pres and poismg
1058             subdomain_size = ( nxr - nxl + 2 * nbgp + 1 ) * &
1059                              ( nyn - nys + 2 * nbgp + 1 ) * ( nzt - nzb + 2 )
1060             gathered_size  = ( nxr_l - nxl_l + 3 ) * ( nyn_l - nys_l + 3 ) *  &
1061                              ( nzt_l - nzb + 2 )
1062
1063#else
1064             message_string = 'multigrid gather/scatter impossible ' //        &
1065                          'in non parallel mode'
1066             CALL message( 'init_pegrid', 'PA0237', 1, 2, 0, 6, 0 )
1067#endif
1068          ENDIF
1069
1070          nxl_mg(i) = nxl_l
1071          nxr_mg(i) = nxr_l
1072          nys_mg(i) = nys_l
1073          nyn_mg(i) = nyn_l
1074          nzt_mg(i) = nzt_l
1075
1076          nxl_l = nxl_l / 2 
1077          nxr_l = nxr_l / 2
1078          nys_l = nys_l / 2 
1079          nyn_l = nyn_l / 2 
1080          nzt_l = nzt_l / 2 
1081
1082       ENDDO
1083
1084!
1085!--    Temporary problem: Currently calculation of maxerror in routine poismg crashes
1086!--    if grid data are collected on PE0 already on the finest grid level.
1087!--    To be solved later.
1088       IF ( maximum_grid_level == mg_switch_to_pe0_level )  THEN
1089          message_string = 'grid coarsening on subdomain level cannot be performed'
1090          CALL message( 'poismg', 'PA0236', 1, 2, 0, 6, 0 )
1091       ENDIF
1092
1093    ELSE
1094
1095       maximum_grid_level = 0
1096
1097    ENDIF
1098
1099!
1100!-- Default level 0 tells exchange_horiz that all ghost planes have to be
1101!-- exchanged. grid_level is adjusted in poismg, where only one ghost plane
1102!-- is required.
1103    grid_level = 0
1104
1105#if defined( __parallel )
1106!
1107!-- Gridpoint number for the exchange of ghost points (y-line for 2D-arrays)
1108    ngp_y  = nyn - nys + 1 + 2 * nbgp
1109
1110!
1111!-- Define new MPI derived datatypes for the exchange of ghost points in
1112!-- x- and y-direction for 2D-arrays (line)
1113    CALL MPI_TYPE_VECTOR( nxr-nxl+1+2*nbgp, nbgp, ngp_y, MPI_REAL, type_x,     &
1114                          ierr )
1115    CALL MPI_TYPE_COMMIT( type_x, ierr )
1116
1117    CALL MPI_TYPE_VECTOR( nbgp, ngp_y, ngp_y, MPI_REAL, type_y, ierr )
1118    CALL MPI_TYPE_COMMIT( type_y, ierr )
1119!
1120!-- Define new MPI derived datatypes for the exchange of ghost points in
1121!-- x- and y-direction for 2D-INTEGER arrays (line) - on normal grid.
1122!-- Define types for 32-bit and 8-bit Integer. The 8-bit Integer are only
1123!-- required on normal grid, while 32-bit Integer may be also required on
1124!-- coarser grid level in case of multigrid solver.
1125!
1126!-- 8-bit Integer
1127    CALL MPI_TYPE_VECTOR( nxr-nxl+1+2*nbgp, nbgp, ngp_y, MPI_BYTE,             &
1128                          type_x_byte, ierr )
1129    CALL MPI_TYPE_COMMIT( type_x_byte, ierr )
1130
1131    CALL MPI_TYPE_VECTOR( nbgp, ngp_y, ngp_y, MPI_BYTE,                        &
1132                          type_y_byte, ierr )
1133    CALL MPI_TYPE_COMMIT( type_y_byte, ierr )
1134!
1135!-- 32-bit Integer
1136    ALLOCATE( type_x_int(0:maximum_grid_level),                                &
1137              type_y_int(0:maximum_grid_level) )
1138             
1139    CALL MPI_TYPE_VECTOR( nxr-nxl+1+2*nbgp, nbgp, ngp_y, MPI_INTEGER,          &
1140                          type_x_int(0), ierr )
1141    CALL MPI_TYPE_COMMIT( type_x_int(0), ierr )
1142
1143    CALL MPI_TYPE_VECTOR( nbgp, ngp_y, ngp_y, MPI_INTEGER, type_y_int(0), ierr )
1144    CALL MPI_TYPE_COMMIT( type_y_int(0), ierr )
1145!
1146!-- Calculate gridpoint numbers for the exchange of ghost points along x
1147!-- (yz-plane for 3D-arrays) and define MPI derived data type(s) for the
1148!-- exchange of ghost points in y-direction (xz-plane).
1149!-- Do these calculations for the model grid and (if necessary) also
1150!-- for the coarser grid levels used in the multigrid method
1151    ALLOCATE ( ngp_xz(0:maximum_grid_level),                                   &
1152               ngp_xz_int(0:maximum_grid_level),                               &
1153               ngp_yz(0:maximum_grid_level),                                   &
1154               ngp_yz_int(0:maximum_grid_level),                               &
1155               type_xz(0:maximum_grid_level),                                  &
1156               type_xz_int(0:maximum_grid_level),                              &
1157               type_yz(0:maximum_grid_level),                                  &
1158               type_yz_int(0:maximum_grid_level) )
1159
1160    nxl_l = nxl; nxr_l = nxr; nys_l = nys; nyn_l = nyn; nzb_l = nzb; nzt_l = nzt
1161
1162!
1163!-- Discern between the model grid, which needs nbgp ghost points and
1164!-- grid levels for the multigrid scheme. In the latter case only one
1165!-- ghost point is necessary.
1166!-- First definition of MPI-datatypes for exchange of ghost layers on normal
1167!-- grid. The following loop is needed for data exchange in poismg.f90.
1168!
1169!-- Determine number of grid points of yz-layer for exchange
1170    ngp_yz(0) = (nzt - nzb + 2) * (nyn - nys + 1 + 2 * nbgp)
1171
1172!
1173!-- Define an MPI-datatype for the exchange of left/right boundaries.
1174!-- Although data are contiguous in physical memory (which does not
1175!-- necessarily require an MPI-derived datatype), the data exchange between
1176!-- left and right PE's using the MPI-derived type is 10% faster than without.
1177    CALL MPI_TYPE_VECTOR( nxr-nxl+1+2*nbgp, nbgp*(nzt-nzb+2), ngp_yz(0), &
1178                          MPI_REAL, type_xz(0), ierr )
1179    CALL MPI_TYPE_COMMIT( type_xz(0), ierr )
1180
1181    CALL MPI_TYPE_VECTOR( nbgp, ngp_yz(0), ngp_yz(0), MPI_REAL, type_yz(0), &
1182                          ierr ) 
1183    CALL MPI_TYPE_COMMIT( type_yz(0), ierr )
1184
1185!
1186!-- Define data types for exchange of 3D Integer arrays.
1187    ngp_yz_int(0) = (nzt - nzb + 2) * (nyn - nys + 1 + 2 * nbgp)
1188
1189    CALL MPI_TYPE_VECTOR( nxr-nxl+1+2*nbgp, nbgp*(nzt-nzb+2), ngp_yz_int(0),   &
1190                          MPI_INTEGER, type_xz_int(0), ierr )
1191    CALL MPI_TYPE_COMMIT( type_xz_int(0), ierr )
1192
1193    CALL MPI_TYPE_VECTOR( nbgp, ngp_yz_int(0), ngp_yz_int(0), MPI_INTEGER,     &
1194                          type_yz_int(0), ierr )
1195    CALL MPI_TYPE_COMMIT( type_yz_int(0), ierr )
1196
1197!
1198!-- Definition of MPI-datatypes for multigrid method (coarser level grids)
1199    IF ( psolver(1:9) == 'multigrid' )  THEN
1200!   
1201!--    Definition of MPI-datatyoe as above, but only 1 ghost level is used
1202       DO  i = maximum_grid_level, 1 , -1
1203!
1204!--       For 3D-exchange on different multigrid level, one ghost point for
1205!--       REAL arrays, two ghost points for INTEGER arrays
1206          ngp_xz(i) = (nzt_l - nzb_l + 2) * (nxr_l - nxl_l + 3)
1207          ngp_yz(i) = (nzt_l - nzb_l + 2) * (nyn_l - nys_l + 3)
1208
1209          ngp_xz_int(i) = (nzt_l - nzb_l + 2) * (nxr_l - nxl_l + 3)
1210          ngp_yz_int(i) = (nzt_l - nzb_l + 2) * (nyn_l - nys_l + 3)
1211!
1212!--       MPI data type for REAL arrays, for xz-layers
1213          CALL MPI_TYPE_VECTOR( nxr_l-nxl_l+3, nzt_l-nzb_l+2, ngp_yz(i),       &
1214                                MPI_REAL, type_xz(i), ierr )
1215          CALL MPI_TYPE_COMMIT( type_xz(i), ierr )
1216
1217!
1218!--       MPI data type for INTEGER arrays, for xz-layers
1219          CALL MPI_TYPE_VECTOR( nxr_l-nxl_l+3, nzt_l-nzb_l+2, ngp_yz_int(i),   &
1220                                MPI_INTEGER, type_xz_int(i), ierr )
1221          CALL MPI_TYPE_COMMIT( type_xz_int(i), ierr )
1222
1223!
1224!--       MPI data type for REAL arrays, for yz-layers
1225          CALL MPI_TYPE_VECTOR( 1, ngp_yz(i), ngp_yz(i), MPI_REAL, type_yz(i), &
1226                                ierr )
1227          CALL MPI_TYPE_COMMIT( type_yz(i), ierr )
1228!
1229!--       MPI data type for INTEGER arrays, for yz-layers
1230          CALL MPI_TYPE_VECTOR( 1, ngp_yz_int(i), ngp_yz_int(i), MPI_INTEGER,  &
1231                                type_yz_int(i), ierr )
1232          CALL MPI_TYPE_COMMIT( type_yz_int(i), ierr )
1233
1234
1235!--       For 2D-exchange of INTEGER arrays on coarser grid level, where 2 ghost
1236!--       points need to be exchanged. Only required for 32-bit Integer arrays.
1237          CALL MPI_TYPE_VECTOR( nxr_l-nxl_l+5, 2, nyn_l-nys_l+5, MPI_INTEGER,  &
1238                                type_x_int(i), ierr )
1239          CALL MPI_TYPE_COMMIT( type_x_int(i), ierr )
1240
1241
1242          CALL MPI_TYPE_VECTOR( 2, nyn_l-nys_l+5, nyn_l-nys_l+5, MPI_INTEGER,  &
1243                                type_y_int(i), ierr )
1244          CALL MPI_TYPE_COMMIT( type_y_int(i), ierr )
1245
1246          nxl_l = nxl_l / 2
1247          nxr_l = nxr_l / 2
1248          nys_l = nys_l / 2
1249          nyn_l = nyn_l / 2
1250          nzt_l = nzt_l / 2
1251
1252       ENDDO
1253
1254    ENDIF
1255
1256#endif
1257
1258#if defined( __parallel )
1259!
1260!-- Setting of flags for inflow/outflow/nesting conditions.
1261    IF ( pleft == MPI_PROC_NULL )  THEN
1262       IF ( bc_lr == 'dirichlet/radiation'  .OR.  bc_lr == 'nested'  .OR.      &
1263            bc_lr == 'nesting_offline' )  THEN
1264          bc_dirichlet_l  = .TRUE.
1265       ELSEIF ( bc_lr == 'radiation/dirichlet' )  THEN
1266          bc_radiation_l = .TRUE.
1267       ENDIF
1268    ENDIF
1269 
1270    IF ( pright == MPI_PROC_NULL )  THEN
1271       IF ( bc_lr == 'dirichlet/radiation' )  THEN
1272          bc_radiation_r = .TRUE.
1273       ELSEIF ( bc_lr == 'radiation/dirichlet'  .OR.  bc_lr == 'nested'  .OR.  &
1274                bc_lr == 'nesting_offline' )  THEN
1275          bc_dirichlet_r  = .TRUE.
1276       ENDIF
1277    ENDIF
1278
1279    IF ( psouth == MPI_PROC_NULL )  THEN
1280       IF ( bc_ns == 'dirichlet/radiation' )  THEN
1281          bc_radiation_s = .TRUE.
1282       ELSEIF ( bc_ns == 'radiation/dirichlet'  .OR.  bc_ns == 'nested'  .OR.  &
1283                bc_ns == 'nesting_offline' )  THEN
1284          bc_dirichlet_s  = .TRUE.
1285       ENDIF
1286    ENDIF
1287
1288    IF ( pnorth == MPI_PROC_NULL )  THEN
1289       IF ( bc_ns == 'dirichlet/radiation'  .OR.  bc_ns == 'nested'  .OR.      &
1290            bc_ns == 'nesting_offline' )  THEN
1291          bc_dirichlet_n  = .TRUE.
1292       ELSEIF ( bc_ns == 'radiation/dirichlet' )  THEN
1293          bc_radiation_n = .TRUE.
1294       ENDIF
1295    ENDIF
1296!
1297!-- In case of synthetic turbulence geneartor determine ids.
1298!-- Please note, if no forcing or nesting is applied, the generator is applied
1299!-- only at the left lateral boundary.
1300    IF ( use_syn_turb_gen )  THEN
1301       IF ( bc_dirichlet_l )  THEN
1302          id_stg_left_l = myidx
1303       ELSE
1304          id_stg_left_l = 0
1305       ENDIF
1306       IF ( bc_dirichlet_r )  THEN
1307          id_stg_right_l = myidx
1308       ELSE
1309          id_stg_right_l = 0
1310       ENDIF
1311       IF ( bc_dirichlet_s )  THEN
1312          id_stg_south_l = myidy
1313       ELSE
1314          id_stg_south_l = 0
1315       ENDIF
1316       IF ( bc_dirichlet_n )  THEN
1317          id_stg_north_l = myidy
1318       ELSE
1319          id_stg_north_l = 0
1320       ENDIF
1321
1322       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1323       CALL MPI_ALLREDUCE( id_stg_left_l, id_stg_left,   1, MPI_INTEGER,       &
1324                           MPI_SUM, comm1dx, ierr )
1325
1326       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1327       CALL MPI_ALLREDUCE( id_stg_right_l, id_stg_right, 1, MPI_INTEGER,       &
1328                           MPI_SUM, comm1dx, ierr )
1329
1330       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1331       CALL MPI_ALLREDUCE( id_stg_south_l, id_stg_south, 1, MPI_INTEGER,       &
1332                           MPI_SUM, comm1dy, ierr )
1333
1334       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1335       CALL MPI_ALLREDUCE( id_stg_north_l, id_stg_north, 1, MPI_INTEGER,       &
1336                           MPI_SUM, comm1dy, ierr )
1337
1338    ENDIF
1339 
1340!
1341!-- Broadcast the id of the inflow PE
1342    IF ( bc_dirichlet_l )  THEN
1343       id_inflow_l = myidx
1344    ELSE
1345       id_inflow_l = 0
1346    ENDIF
1347    IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1348    CALL MPI_ALLREDUCE( id_inflow_l, id_inflow, 1, MPI_INTEGER, MPI_SUM, &
1349                        comm1dx, ierr )
1350
1351!
1352!-- Broadcast the id of the recycling plane
1353!-- WARNING: needs to be adjusted in case of inflows other than from left side!
1354    IF ( NINT( recycling_width / dx ) >= nxl  .AND. &
1355         NINT( recycling_width / dx ) <= nxr )  THEN
1356       id_recycling_l = myidx
1357    ELSE
1358       id_recycling_l = 0
1359    ENDIF
1360    IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1361    CALL MPI_ALLREDUCE( id_recycling_l, id_recycling, 1, MPI_INTEGER, MPI_SUM, &
1362                        comm1dx, ierr )
1363
1364!
1365!-- Broadcast the id of the outflow PE and outflow-source plane
1366    IF ( turbulent_outflow )  THEN
1367
1368       IF ( bc_radiation_r )  THEN
1369          id_outflow_l = myidx
1370       ELSE
1371          id_outflow_l = 0
1372       ENDIF
1373       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1374       CALL MPI_ALLREDUCE( id_outflow_l, id_outflow, 1, MPI_INTEGER, MPI_SUM, &
1375                           comm1dx, ierr )
1376
1377       IF ( NINT( outflow_source_plane / dx ) >= nxl  .AND. &
1378            NINT( outflow_source_plane / dx ) <= nxr )  THEN
1379          id_outflow_source_l = myidx
1380       ELSE
1381          id_outflow_source_l = 0
1382       ENDIF
1383       IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
1384       CALL MPI_ALLREDUCE( id_outflow_source_l, id_outflow_source, 1, &
1385                           MPI_INTEGER, MPI_SUM, comm1dx, ierr )
1386
1387    ENDIF
1388
1389    CALL location_message( 'finished', .TRUE. )
1390
1391#else
1392    IF ( bc_lr == 'dirichlet/radiation' )  THEN
1393       bc_dirichlet_l = .TRUE.
1394       bc_radiation_r = .TRUE.
1395    ELSEIF ( bc_lr == 'radiation/dirichlet' )  THEN
1396       bc_radiation_l = .TRUE.
1397       bc_dirichlet_r = .TRUE.
1398    ENDIF
1399
1400    IF ( bc_ns == 'dirichlet/radiation' )  THEN
1401       bc_dirichlet_n = .TRUE.
1402       bc_radiation_s = .TRUE.
1403    ELSEIF ( bc_ns == 'radiation/dirichlet' )  THEN
1404       bc_radiation_n = .TRUE.
1405       bc_dirichlet_s = .TRUE.
1406    ENDIF
1407#endif
1408
1409!
1410!-- At the inflow or outflow, u or v, respectively, have to be calculated for
1411!-- one more grid point.
1412    IF ( bc_dirichlet_l  .OR.  bc_radiation_l )  THEN
1413       nxlu = nxl + 1
1414    ELSE
1415       nxlu = nxl
1416    ENDIF
1417    IF ( bc_dirichlet_s  .OR.  bc_radiation_s )  THEN
1418       nysv = nys + 1
1419    ELSE
1420       nysv = nys
1421    ENDIF
1422
1423!
1424!-- Allocate wall flag arrays used in the multigrid solver
1425    IF ( psolver(1:9) == 'multigrid' )  THEN
1426
1427       DO  i = maximum_grid_level, 1, -1
1428
1429           SELECT CASE ( i )
1430
1431              CASE ( 1 )
1432                 ALLOCATE( wall_flags_1(nzb:nzt_mg(i)+1,         &
1433                                        nys_mg(i)-1:nyn_mg(i)+1, &
1434                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1435
1436              CASE ( 2 )
1437                 ALLOCATE( wall_flags_2(nzb:nzt_mg(i)+1,         &
1438                                        nys_mg(i)-1:nyn_mg(i)+1, &
1439                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1440
1441              CASE ( 3 )
1442                 ALLOCATE( wall_flags_3(nzb:nzt_mg(i)+1,         &
1443                                        nys_mg(i)-1:nyn_mg(i)+1, &
1444                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1445
1446              CASE ( 4 )
1447                 ALLOCATE( wall_flags_4(nzb:nzt_mg(i)+1,         &
1448                                        nys_mg(i)-1:nyn_mg(i)+1, &
1449                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1450
1451              CASE ( 5 )
1452                 ALLOCATE( wall_flags_5(nzb:nzt_mg(i)+1,         &
1453                                        nys_mg(i)-1:nyn_mg(i)+1, &
1454                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1455
1456              CASE ( 6 )
1457                 ALLOCATE( wall_flags_6(nzb:nzt_mg(i)+1,         &
1458                                        nys_mg(i)-1:nyn_mg(i)+1, &
1459                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1460
1461              CASE ( 7 )
1462                 ALLOCATE( wall_flags_7(nzb:nzt_mg(i)+1,         &
1463                                        nys_mg(i)-1:nyn_mg(i)+1, &
1464                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1465
1466              CASE ( 8 )
1467                 ALLOCATE( wall_flags_8(nzb:nzt_mg(i)+1,         &
1468                                        nys_mg(i)-1:nyn_mg(i)+1, &
1469                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1470
1471              CASE ( 9 )
1472                 ALLOCATE( wall_flags_9(nzb:nzt_mg(i)+1,         &
1473                                        nys_mg(i)-1:nyn_mg(i)+1, &
1474                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1475
1476              CASE ( 10 )
1477                 ALLOCATE( wall_flags_10(nzb:nzt_mg(i)+1,        &
1478                                        nys_mg(i)-1:nyn_mg(i)+1, &
1479                                        nxl_mg(i)-1:nxr_mg(i)+1) )
1480
1481              CASE DEFAULT
1482                 message_string = 'more than 10 multigrid levels'
1483                 CALL message( 'init_pegrid', 'PA0238', 1, 2, 0, 6, 0 )
1484
1485          END SELECT
1486
1487       ENDDO
1488
1489    ENDIF
1490
1491 END SUBROUTINE init_pegrid
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