SUBROUTINE lpm_read_restart_file

!--------------------------------------------------------------------------------!
! 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 1997-2014 Leibniz Universitaet Hannover
!--------------------------------------------------------------------------------!
!
! Current revisions:
! ------------------
!
!
! Former revisions:
! -----------------
! $Id: lpm_read_restart_file.f90 1321 2014-03-20 09:40:40Z maronga $
!
! 1320 2014-03-20 08:40:49Z raasch
! ONLY-attribute added to USE-statements,
! comment fields (!:) to be used for variable explanations added to
! all variable declaration statements
!
! 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 init_particles)
!
!
! Description:
! ------------
! Read particle data from the restart file.
!------------------------------------------------------------------------------!

    USE control_parameters,                                                    &
        ONLY:  message_string

    USE indices,                                                               &
        ONLY:  nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, nzb, nzt

    USE particle_attributes,                                                   &
        ONLY:  bc_par_b, bc_par_lr, bc_par_ns, bc_par_t, initial_particles,    &
               number_of_initial_particles, maximum_number_of_particles,       &
               maximum_number_of_tailpoints, maximum_number_of_tails,          &
               new_tail_id, number_of_particles, number_of_particle_groups,    &
               number_of_tails, particles, particle_groups, particle_mask,     &
               particle_tail_coordinates, particle_type, part_1, part_2,       &
               prt_count, prt_start_index,  sort_count, tail_mask, time_prel,  &
               time_write_particle_data, uniform_particles, use_particle_tails


    USE pegrid

    IMPLICIT NONE

    CHARACTER (LEN=10) ::  particle_binary_version    !:
    CHARACTER (LEN=10) ::  version_on_file            !:

!
!-- Read particle data from previous model run.
!-- First open the input unit.
    IF ( myid_char == '' )  THEN
       OPEN ( 90, FILE='PARTICLE_RESTART_DATA_IN'//myid_char, &
                  FORM='UNFORMATTED' )
    ELSE
       OPEN ( 90, FILE='PARTICLE_RESTART_DATA_IN/'//myid_char, &
                  FORM='UNFORMATTED' )
    ENDIF

!
!-- First compare the version numbers
    READ ( 90 )  version_on_file
    particle_binary_version = '3.0'
    IF ( TRIM( version_on_file ) /= TRIM( particle_binary_version ) )  THEN
       message_string = 'version mismatch concerning data from prior ' // &
                        'run &version on file    = "' //                  &
                                      TRIM( version_on_file ) //          &
                        '&version in program = "' //                      &
                                      TRIM( particle_binary_version ) // '"'
       CALL message( 'lpm_read_restart_file', 'PA0214', 1, 2, 0, 6, 0 )
    ENDIF

!
!-- Read some particle parameters and the size of the particle arrays,
!-- allocate them and read their contents.
    READ ( 90 )  bc_par_b, bc_par_lr, bc_par_ns, bc_par_t,                  &
                 maximum_number_of_particles, maximum_number_of_tailpoints, &
                 maximum_number_of_tails, number_of_initial_particles,      &
                 number_of_particles, number_of_particle_groups,            &
                 number_of_tails, particle_groups, time_prel,               &
                 time_write_particle_data, uniform_particles

    IF ( number_of_initial_particles /= 0 )  THEN
       ALLOCATE( initial_particles(1:number_of_initial_particles) )
       READ ( 90 )  initial_particles
    ENDIF

    ALLOCATE( prt_count(nzb:nzt+1,nysg:nyng,nxlg:nxrg),       &
              prt_start_index(nzb:nzt+1,nysg:nyng,nxlg:nxrg), &
              particle_mask(maximum_number_of_particles),     &
              part_1(maximum_number_of_particles),            &
              part_2(maximum_number_of_particles) )

    part_1 = particle_type( 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, &
                            0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, &
                            0.0, 0, 0, 0, 0 )

    part_2 = particle_type( 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, &
                            0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, &
                            0.0, 0, 0, 0, 0 )

    sort_count = 0

    particles => part_1

    READ ( 90 )  prt_count, prt_start_index
    READ ( 90 )  particles

    IF ( use_particle_tails )  THEN
       ALLOCATE( particle_tail_coordinates(maximum_number_of_tailpoints,5, &
                 maximum_number_of_tails),                                 &
                 new_tail_id(maximum_number_of_tails),                     &
                 tail_mask(maximum_number_of_tails) )
       READ ( 90 )  particle_tail_coordinates
    ENDIF

    CLOSE ( 90 )


 END SUBROUTINE lpm_read_restart_file