source: palm/trunk/SOURCE/lpm_sort_arrays.f90 @ 1203

 SUBROUTINE lpm_sort_arrays

!--------------------------------------------------------------------------------!
! This file is part of PALM.
!
! PALM is free software: you can redistribute it and/or modify it under the terms
! of the GNU General Public License as published by the Free Software Foundation,
! either version 3 of the License, or (at your option) any later version.
!
! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
! A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
!
! You should have received a copy of the GNU General Public License along with
! PALM. If not, see <http://www.gnu.org/licenses/>.
!
! Copyright 1997-2012  Leibniz University Hannover
!--------------------------------------------------------------------------------!
!
! Current revisions:
! ------------------
! 
!
! Former revisions:
! -----------------
! $Id: lpm_sort_arrays.f90 1037 2012-10-22 14:10:22Z witha $
!
! 1036 2012-10-22 13:43:42Z raasch
! code put under GPL (PALM 3.9)
!
! 849 2012-03-15 10:35:09Z raasch
! initial revision (former part of advec_particles)
!
!
! Description:
! ------------
! Sort particles in the sequence the grid boxes are stored in memory.
!------------------------------------------------------------------------------!

    USE arrays_3d
    USE control_parameters
    USE cpulog
    USE grid_variables
    USE indices
    USE interfaces
    USE particle_attributes

    IMPLICIT NONE

    INTEGER ::  i, ilow, j, k, n

    TYPE(particle_type), DIMENSION(:), POINTER ::  particles_temp


    CALL cpu_log( log_point_s(47), 'lpm_sort_arrays', 'start' )

!
!-- Initialize counters and set pointer of the temporary array into which
!-- particles are sorted to free memory
    prt_count  = 0
    sort_count = sort_count +1

    SELECT CASE ( MOD( sort_count, 2 ) )

       CASE ( 0 )

          particles_temp => part_1

       CASE ( 1 )

          particles_temp => part_2

    END SELECT

!
!-- Count the particles per gridbox
    DO  n = 1, number_of_particles

       i = ( particles(n)%x + 0.5 * dx ) * ddx
       j = ( particles(n)%y + 0.5 * dy ) * ddy
       k = particles(n)%z / dz + 1 + offset_ocean_nzt
           ! only exact if equidistant

       prt_count(k,j,i) = prt_count(k,j,i) + 1

       IF ( i < nxl .OR. i > nxr .OR. j < nys .OR. j > nyn .OR. k < nzb+1 .OR. &
            k > nzt )  THEN
          WRITE( message_string, * ) ' particle out of range: i=', i, ' j=', &
                          j, ' k=', k,                                       &
                          ' nxl=', nxl, ' nxr=', nxr,                        &
                          ' nys=', nys, ' nyn=', nyn,                        &
                          ' nzb=', nzb, ' nzt=', nzt
         CALL message( 'lpm_sort_arrays', 'PA0149', 1, 2, 0, 6, 0 ) 
       ENDIF

    ENDDO

!
!-- Calculate the lower indices of those ranges of the particles-array
!-- containing particles which belong to the same gridpox i,j,k
    ilow = 1
    DO  i = nxl, nxr
       DO  j = nys, nyn
          DO  k = nzb+1, nzt
             prt_start_index(k,j,i) = ilow
             ilow = ilow + prt_count(k,j,i)
          ENDDO
       ENDDO
    ENDDO

!
!-- Sorting the particles
    DO  n = 1, number_of_particles

       i = ( particles(n)%x + 0.5 * dx ) * ddx
       j = ( particles(n)%y + 0.5 * dy ) * ddy
       k = particles(n)%z / dz + 1 + offset_ocean_nzt
           ! only exact if equidistant

       particles_temp(prt_start_index(k,j,i)) = particles(n)

       prt_start_index(k,j,i) = prt_start_index(k,j,i) + 1

    ENDDO

!
!-- Redirect the particles pointer to the sorted array
    SELECT CASE ( MOD( sort_count, 2 ) )

       CASE ( 0 )

          particles => part_1

       CASE ( 1 )

          particles => part_2

    END SELECT

!
!-- Reset the index array to the actual start position
    DO  i = nxl, nxr
       DO  j = nys, nyn
          DO  k = nzb+1, nzt
             prt_start_index(k,j,i) = prt_start_index(k,j,i) - prt_count(k,j,i)
          ENDDO
       ENDDO
    ENDDO

    CALL cpu_log( log_point_s(47), 'lpm_sort_arrays', 'stop' )


 END SUBROUTINE lpm_sort_arrays