restart.F90

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!! Copyright (C) 2002-2006 M. Marques, A. Castro, A. Rubio, G. Bertsch
!! Copyright (C) 2014 M. Oliveira
!! Copyright (C) 2021 S. Ohlmann
!!
!! This program 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 2, or (at your option)
!! any later version.
!!
!! This program 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 this program; if not, write to the Free Software
!! Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
!! 02110-1301, USA.
!!
 
#include "global.h"
 
module restart_oct_m
  use batch_oct_m
  use calc_mode_par_oct_m
  use debug_oct_m
  use global_oct_m
  use index_oct_m
  use io_oct_m
  use io_binary_oct_m
  use loct_oct_m
  use mesh_oct_m
  use mesh_batch_oct_m
  use messages_oct_m
  use mpi_oct_m
  use multicomm_oct_m
  use namespace_oct_m
  use parser_oct_m
  use par_vec_oct_m
  use profiling_oct_m
  use space_oct_m
  use unit_system_oct_m
 
  implicit none
 
  private
  public ::                       &
    restart_t,                    &
    clean_stop,                   &
    restart_module_init,          &
    restart_init,                 &
    restart_end,                  &
    restart_dir,                  &
    restart_open_dir,             &
    restart_close_dir,            &
    restart_mkdir,                &
    restart_rm,                   &
    restart_open,                 &
    restart_write,                &
    restart_read,                 &
    restart_close,                &
    restart_block_signals,        &
    restart_unblock_signals,      &
    restart_skip,                 &
    restart_has_flag,             &
    restart_has_map,              &
    restart_write_mesh_function,  &
    restart_read_mesh_function,   &
    drestart_write_binary,        &
    zrestart_write_binary,        &
    drestart_read_binary,         &
    zrestart_read_binary,         &
    restart_are_basedirs_equal
 
  interface drestart_write_binary
    module procedure drestart_write_binary1, drestart_write_binary2, drestart_write_binary3, drestart_write_binary5
    module procedure drestart_write_binary1_int32, drestart_write_binary2_int32, drestart_write_binary3_int32, &
      drestart_write_binary5_int32
  end interface drestart_write_binary
 
  interface zrestart_write_binary
    module procedure zrestart_write_binary1, zrestart_write_binary2, zrestart_write_binary3, zrestart_write_binary5
    module procedure zrestart_write_binary1_int32, zrestart_write_binary2_int32, zrestart_write_binary3_int32, &
      zrestart_write_binary5_int32
  end interface zrestart_write_binary
 
  interface drestart_read_binary
    module procedure drestart_read_binary1, drestart_read_binary2, drestart_read_binary3, drestart_read_binary5
    module procedure drestart_read_binary1_int32, drestart_read_binary2_int32, drestart_read_binary3_int32, &
      drestart_read_binary5_int32
  end interface drestart_read_binary
 
  interface zrestart_read_binary
    module procedure zrestart_read_binary1, zrestart_read_binary2, zrestart_read_binary3, zrestart_read_binary5
    module procedure zrestart_read_binary1_int32, zrestart_read_binary2_int32, zrestart_read_binary3_int32, &
      zrestart_read_binary5_int32
  end interface zrestart_read_binary
 
  interface restart_read_mesh_function
    module procedure drestart_read_mesh_function, zrestart_read_mesh_function
  end interface restart_read_mesh_function
 
  interface restart_write_mesh_function
    module procedure drestart_write_mesh_function, zrestart_write_mesh_function
  end interface restart_write_mesh_function
 
  integer, parameter, public :: &
    RESTART_UNDEFINED  = -1,    &
    restart_all        =  0,    &
    restart_gs         =  1,    &
    restart_unocc      =  2,    &
    restart_td         =  3,    &
    restart_em_resp    =  4,    &
    restart_em_resp_fd =  5,    &
    restart_kdotp      =  6,    &
    restart_vib_modes  =  7,    &
    restart_vdw        =  8,    &
    restart_casida     =  9,    &
    restart_oct        =  10,   &
    restart_partition  =  11,   &
    restart_proj       =  12
 
  integer, parameter :: RESTART_N_DATA_TYPES = 12
 
  type restart_t
    private
    integer      :: data_type = restart_undefined  
    integer      :: type = restart_undefined       
    logical      :: skip
    character(len=MAX_PATH_LEN) :: dir
    character(len=MAX_PATH_LEN) :: pwd
    type(namespace_t), pointer, public :: namespace
    type(mpi_grp_t)   :: mpi_grp
    type(multicomm_t), pointer :: mc
    logical           :: has_mesh
    integer(int64), allocatable :: map(:)
    !                                     !! the mesh used in the current calculations.
  contains
    procedure :: get_data_type => restart_get_data_type
  end type restart_t
 
 
  type restart_data_t
    private
    character(len=20) :: tag
    character(len=MAX_PATH_LEN) :: basedir
    character(len=MAX_PATH_LEN) :: dir
    integer :: flags
  end type restart_data_t
 
 
  integer, parameter, public :: &
    RESTART_TYPE_DUMP = 1,      &
    restart_type_load = 2
 
  integer, parameter, public :: &
    RESTART_FLAG_STATES = 1,    &
    restart_flag_rho    = 2,    &
    restart_flag_vhxc   = 4,    &
    restart_flag_mix    = 8,    &
    restart_flag_skip   = 16
 
  type(restart_data_t) :: info(RESTART_N_DATA_TYPES)
 
 
  interface restart_block_signals
    subroutine block_signals()
      implicit none
    end subroutine block_signals
  end interface restart_block_signals
 
  interface restart_unblock_signals
    subroutine unblock_signals()
      implicit none
    end subroutine unblock_signals
  end interface
 
contains
 
  function clean_stop(comm)
    type(MPI_Comm), intent(in) :: comm
 
    logical :: clean_stop, file_exists
 
    push_sub(clean_stop)
 
    clean_stop = .false.
 
    if (mpi_grp_is_root(mpi_world)) then
      inquire(file='stop', exist=file_exists)
      if (file_exists) then
        call loct_rm('stop')
        clean_stop = .true.
      end if
    end if
 
#ifdef HAVE_MPI
    ! make sure all nodes agree on whether this condition occurred
    call mpi_bcast(clean_stop, 1, mpi_logical, 0, comm, mpi_err)
#endif
 
    if (clean_stop) then
      message(1) = 'Clean STOP'
      call messages_warning(1)
    end if
 
    pop_sub(clean_stop)
  end function clean_stop
 
 
  ! ---------------------------------------------------------
  subroutine restart_module_init(namespace)
    type(namespace_t),         intent(in)    :: namespace
 
    logical :: set(RESTART_N_DATA_TYPES)
    integer :: iline, n_cols, data_type
    character(len=MAX_PATH_LEN) :: default_basedir
    type(block_t) :: blk
 
    push_sub(restart_module_init)
 
    ! Each data type should have a tag
    info(restart_gs)%tag = "Ground-state"
    info(restart_unocc)%tag = "Unoccupied states"
    info(restart_td)%tag = "Time-dependent"
    info(restart_em_resp)%tag = "EM Resp."
    info(restart_em_resp_fd)%tag = "EM Resp. FD"
    info(restart_kdotp)%tag = "KdotP"
    info(restart_vib_modes)%tag = "Vib. Modes"
    info(restart_vdw)%tag = "VdW"
    info(restart_casida)%tag = "Casida"
    info(restart_oct)%tag = "Optimal Control"
    info(restart_proj)%tag = "GS for TDOutput"
    info(restart_partition)%tag = "Mesh Partition"
 
    ! Default flags and directories (flags not yet used)
    info(:)%basedir = 'restart'
    info(:)%flags = 0
    info(restart_partition)%flags = restart_flag_skip
 
    info(restart_gs)%dir = gs_dir
    info(restart_unocc)%dir = gs_dir
    info(restart_td)%dir = td_dir
    info(restart_em_resp)%dir = em_resp_dir
    info(restart_em_resp_fd)%dir = em_resp_fd_dir
    info(restart_kdotp)%dir = kdotp_dir
    info(restart_vib_modes)%dir = vib_modes_dir
    info(restart_vdw)%dir = vdw_dir
    info(restart_casida)%dir = casida_dir
    info(restart_oct)%dir = oct_dir
    info(restart_proj)%dir = gs_dir
    info(restart_partition)%dir = partition_dir
 
    ! Read input
    call messages_obsolete_variable(namespace, 'RestartFileFormat', 'RestartOptions')
    call messages_obsolete_variable(namespace, 'TmpDir', 'RestartOptions')
    call messages_obsolete_variable(namespace, 'RestartDir', 'RestartOptions')
    call messages_obsolete_variable(namespace, 'MeshPartitionRead', 'RestartOptions')
    call messages_obsolete_variable(namespace, 'MeshPartitionWrite', 'RestartOptions')
    call messages_obsolete_variable(namespace, 'MeshPartitionDir', 'RestartOptions')
 
    !%Variable RestartOptions
    !%Type block
    !%Section Execution::IO
    !%Description
    !% <tt>Octopus</tt> usually stores binary information, such as the wavefunctions, to be used
    !% in subsequent calculations. The most common example is the ground-state states
    !% that are used to start a time-dependent calculation. This variable allows to control
    !% where this information is written to or read from. The format of this block is the following:
    !% for each line, the first column indicates the type of data, the second column indicates
    !% the path to the directory that should be used to read and write that restart information, and the
    !% third column, which is optional, allows one to set some flags to modify the way how the data
    !% is read or written. For example, if you are running a time-dependent calculation, you can
    !% indicate where <tt>Octopus</tt> can find the ground-state information in the following way:
    !%
    !% <tt>%RestartOptions
    !% <br>&nbsp;&nbsp;restart_gs | "gs_restart"
    !% <br>&nbsp;&nbsp;restart_td | "td_restart"
    !% <br>%</tt>
    !%
    !% The second line of the above example also tells <tt>Octopus</tt> that the time-dependent restart data
    !% should be read from and written to the "td_restart" directory.
    !%
    !% In case you want to change the path of all the restart directories, you can use the <tt>restart_all</tt> option.
    !% When using the <tt>restart_all</tt> option, it is still possible to have a different restart directory for specific
    !% data types. For example, when including the following block in your input file:
    !%
    !% <tt>%RestartOptions
    !% <br>&nbsp;&nbsp;restart_all | "my_restart"
    !% <br>&nbsp;&nbsp;restart_td&nbsp;  | "td_restart"
    !% <br>%</tt>
    !%
    !% the time-dependent restart information will be stored in the "td_restart" directory, while all the remaining
    !% restart information will be stored in the "my_restart" directory.
    !%
    !% By default, the name of the "restart_all" directory is set to "restart".
    !%
    !% Some <tt>CalculationMode</tt>s also take into account specific flags set in the third column of the <tt>RestartOptions</tt>
    !% block. These are used to determine if some specific part of the restart data is to be taken into account
    !% or not when reading the restart information. For example, when restarting a ground-state calculation, one can
    !% set the <tt>restart_rho</tt> flags, so that the density used is not built from the saved wavefunctions, but is
    !% instead read from the restart directory. In this case, the block should look like this:
    !%
    !% <tt>%RestartOptions
    !% <br>&nbsp;&nbsp;restart_gs | "restart" | restart_rho
    !% <br>%</tt>
    !%
    !% A list of available flags is given below, but note that the code might ignore some of them, which will happen if they
    !% are not available for that particular calculation, or might assume some of them always present, which will happen
    !% in case they are mandatory.
    !%
    !% Finally, note that all the restart information of a given data type is always stored in a subdirectory of the
    !% specified path. The name of this subdirectory is fixed and cannot be changed. For example, ground-state information
    !% will always be stored in a subdirectory named "gs". This makes it safe in most situations to use the same path for
    !% all the data types. The name of these subdirectories is indicated in the description of the data types below.
    !%
    !% Currently, the available restart data types and flags are the following:
    !%Option restart_all 0
    !% (data type)
    !% Option to globally change the path of all the restart information.
    !%Option restart_gs  1
    !% (data type)
    !% The data resulting from a ground-state calculation.
    !% This information is stored under the "gs" subdirectory.
    !%Option restart_unocc 2
    !% (data type)
    !% The data resulting from an unoccupied states calculation. This information also corresponds to a ground state and
    !% can be used as such, so it is stored under the same subdirectory as the one of restart_gs.
    !%Option restart_td 3
    !% (data type)
    !% The data resulting from a real-time time-dependent calculation.
    !% This information is stored under the "td" subdirectory.
    !%Option restart_em_resp 4
    !% (data type)
    !% The data resulting from the calculation of the electromagnetic response using the Sternheimer approach.
    !% This information is stored under the "em_resp" subdirectory.
    !%Option restart_em_resp_fd 5
    !% (data type)
    !% The data resulting from the calculation of the electromagnetic response using finite-differences.
    !% This information is stored under the "em_resp_fd" subdirectory.
    !%Option restart_kdotp 6
    !% (data type)
    !% The data resulting from the calculation of effective masses by k.p perturbation theory.
    !% This information is stored under the "kdotp" subdirectory.
    !%Option restart_vib_modes 7
    !% (data type)
    !% The data resulting from the calculation of vibrational modes.
    !% This information is stored under the "vib_modes" subdirectory.
    !%Option restart_vdw 8
    !% (data type)
    !% The data resulting from the calculation of van der Waals coefficients.
    !% This information is stored under the "vdw" subdirectory.
    !%Option restart_casida 9
    !% (data type)
    !% The data resulting from a Casida calculation.
    !% This information is stored under the "casida" subdirectory.
    !%Option restart_oct 10
    !% (data type)
    !% The data for optimal control calculations.
    !% This information is stored under the "opt-control" subdirectory.
    !%Option restart_partition 11
    !% (data type)
    !% The data for the mesh partitioning.
    !% This information is stored under the "partition" subdirectory.
    !%Option restart_proj 12
    !% (data type)
    !% The ground-state to be used with the td_occup and populations options of <tt>TDOutput</tt>.
    !% This information should be a ground state, so the "gs" subdirectory is used.
    !%Option restart_states 1
    !% (flag)
    !% Read the electronic states. (not yet implemented)
    !%Option restart_rho 2
    !% (flag)
    !% Read the electronic density.
    !%Option restart_vhxc 4
    !% (flag)
    !% Read the Hartree and XC potentials.
    !%Option restart_mix 8
    !% (flag)
    !% Read the SCF mixing information.
    !%Option restart_skip 16
    !% (flag)
    !% This flag allows to selectively skip the reading and writting of specific restart information.
    !%End
    set = .false.
    if (parse_block(namespace, 'RestartOptions', blk) == 0) then
 
      default_basedir = 'restart'
 
      do iline = 1, parse_block_n(blk)
        n_cols = parse_block_cols(blk,iline-1)
 
        call parse_block_integer(blk, iline-1, 0, data_type)
        if (data_type < 0 .or. data_type > restart_n_data_types) then
          call messages_input_error(namespace, 'RestartOptions', "Invalid data type", row=iline-1, column=0)
        end if
        if (data_type == 0) then
          call parse_block_string(blk, iline-1, 1, default_basedir)
        else
          set(data_type) = .true.
          call parse_block_string(blk, iline-1, 1, info(data_type)%basedir)
 
          if (n_cols > 2) call parse_block_integer(blk, iline-1, 2, info(data_type)%flags)
        end if
 
      end do
      call parse_block_end(blk)
 
      where (.not. set)
        info(:)%basedir = default_basedir
      end where
    end if
 
    pop_sub(restart_module_init)
  end subroutine restart_module_init
 
 
  ! ---------------------------------------------------------
  subroutine restart_init(restart, namespace, data_type, type, mc, ierr, mesh, dir, exact)
    type(restart_t),             intent(out) :: restart
    type(namespace_t), target,   intent(in)  :: namespace
    integer,                     intent(in)  :: data_type
    integer,                     intent(in)  :: type
    type(multicomm_t), target,   intent(in)  :: mc
    integer,                     intent(out) :: ierr
    class(mesh_t),     optional, intent(in)  :: mesh
    character(len=*),  optional, intent(in)  :: dir
    logical,           optional, intent(in)  :: exact
 
    logical :: grid_changed, grid_reordered, restart_write, dir_exists
    character(len=20) :: tag
    character(len=MAX_PATH_LEN) :: basedir, dirname
 
    push_sub(restart_init)
 
    ierr = 0
 
    ! Sanity checks
    if (present(exact) .and. .not. present(mesh)) then
      message(1) = "Error in restart_init: the 'exact' optional argument requires a mesh."
      call messages_fatal(1, namespace=namespace)
    end if
 
    restart%has_mesh = present(mesh)
 
    ! Some initializations
    restart%type = type
    restart%mc => mc
    call mpi_grp_init(restart%mpi_grp, mc%master_comm)
    if (data_type < restart_undefined .and. data_type > restart_n_data_types) then
      message(1) = "Illegal data_type in restart_init"
      call messages_fatal(1, namespace=namespace)
    end if
    restart%data_type = data_type
    restart%namespace => namespace
 
    select case (restart%type)
    case (restart_type_dump)
      !%Variable RestartWrite
      !%Type logical
      !%Default true
      !%Section Execution::IO
      !%Description
      !% If this variable is set to no, restart information is not
      !% written. Note that some run modes will ignore this
      !% option and write some restart information anyway.
      !%End
 
      call parse_variable(namespace, 'RestartWrite', .true., restart_write)
      restart%skip = .not. restart_write
 
      if (restart%skip) then
        message(1) = 'Restart information will not be written.'
        call messages_info(1, namespace=namespace)
      end if
 
    case (restart_type_load)
      ! This is set to true as an error condition, checked by assertions in some routines.
      restart%skip = .false.
 
    case default
      message(1) = "Unknown restart type in restart_init"
      call messages_fatal(1, namespace=namespace)
    end select
 
 
    ! If the restart data type is not defined, the directories should be set explicitly
    if (restart%data_type == restart_undefined) then
      assert(present(dir))
      basedir = dir
      dirname = ""
    else
      basedir = info(restart%data_type)%basedir
      if (index(basedir, '/', .true.) /= len_trim(basedir)) then
        basedir = trim(basedir)//"/"
      end if
      dirname = info(restart%data_type)%dir
    end if
 
    ! Set final path
    restart%dir = trim(basedir)//trim(dirname)
    ! Remove any trailing "/" from the path (all the routines from this module should add the trailing "/" when needed)
    if (index(restart%dir, '/', .true.) == len_trim(restart%dir)) then
      restart%dir = restart%dir(1:len_trim(restart%dir)-1)
    end if
 
    ! Set initial path to the working directory
    restart%pwd = restart%dir
    ! Check if the directory already exists and create it if necessary
    if (mpi_grp_is_root(restart%mpi_grp)) then
      dir_exists = io_dir_exists(trim(restart%pwd), namespace)
      if (restart%type == restart_type_dump .and. .not. dir_exists) then
        call io_mkdir(trim(restart%pwd), namespace, parents=.true.)
      end if
    end if
    if (restart%mpi_grp%size > 1) then
      call restart%mpi_grp%bcast(dir_exists, 1, mpi_logical, 0)
    end if
 
    if (restart%data_type == restart_undefined) then
      tag = "Some "
    else
      tag = info(data_type)%tag
    end if
 
    select case (restart%type)
    case (restart_type_dump)
      if (.not. restart%skip) then
        message(1) = "Info: "//trim(tag)//" restart information will be written to '"//trim(restart%pwd)//"'."
        call messages_info(1, namespace=namespace)
 
        ! Dump the grid information. The main parameters of the grid should not change
        ! during the calculation, so we should only need to dump it once.
        if (present(mesh)) then
          call index_dump(mesh%idx, mesh%np_part_global, restart%pwd, restart%mpi_grp, &
            restart%namespace, ierr)
          if (ierr /= 0) then
            message(1) = "Unable to write index map to '"//trim(restart%pwd)//"'."
            call messages_fatal(1, namespace=namespace)
          end if
 
          call mesh_write_fingerprint(mesh, restart%pwd, "grid", restart%mpi_grp, namespace, ierr)
          if (ierr /= 0) then
            message(1) = "Unable to write mesh fingerprint to '"//trim(restart%pwd)//"/grid'."
            call messages_fatal(1, namespace=namespace)
          end if
        end if
 
      end if
 
    case (restart_type_load)
      if (.not. dir_exists) then
        ierr = 1
        restart%skip = .true.
 
        message(1) = "Info: Could not find '"//trim(restart%pwd)//"' directory for restart."
        message(2) = "Info: No restart information will be read."
        call messages_info(2, namespace=namespace)
 
      else
        message(1) = "Info: "//trim(tag)//" restart information will be read from '"//trim(restart%pwd)//"'."
        call messages_info(1, namespace=namespace)
 
        if (present(mesh)) then
          call mesh_check_dump_compatibility(mesh, restart%pwd, "grid", restart%namespace, &
            restart%mpi_grp, grid_changed, grid_reordered, restart%map, ierr)
 
          ! Check whether an error occurred. In this case we cannot read.
          if (ierr /= 0) then
            if (ierr == -1) then
              message(1) = "Unable to check mesh compatibility: unable to read mesh fingerprint"
              message(2) = "in '"//trim(restart%pwd)//"'."
            else if (ierr > 0) then
              message(1) = "Mesh from current calculation is not compatible with mesh found in"
              message(2) = "'"//trim(restart%pwd)//"'."
            end if
            message(3) = "No restart information will be read."
            call messages_warning(3, namespace=namespace)
            ierr = 1
          end if
 
          ! Print some warnings in case the mesh is compatible, but changed.
          if (grid_changed) then
            if (grid_reordered) then
              message(1) = "Info: Octopus is attempting to restart from a mesh with a different order of points."
            else
              message(1) = "Info: Octopus is attempting to restart from a different mesh."
            end if
            call messages_info(1, namespace=namespace)
          end if
 
          if (present(exact)) then
            restart%skip = grid_changed .and. .not. grid_reordered .and. exact
            if (restart%skip) then
              message(1) = "This calculation requires the exact same mesh to restart."
              message(2) = "No restart information will be read from '"//trim(restart%pwd)//"'."
              call messages_warning(2, namespace=namespace)
              ierr = 1
            end if
          else
            restart%skip = .false.
          end if
        end if
      end if
 
    end select
 
 
    ! Make sure all the processes have finished reading/writing all the grid information,
    ! as there might be some subsequent calls to this function where that information will
    ! be written/read to/from the same directory.
    if (restart%mpi_grp%size > 1) then
      call restart%mpi_grp%barrier()
    end if
 
    pop_sub(restart_init)
  end subroutine restart_init
 
 
  ! ---------------------------------------------------------
  subroutine restart_end(restart)
    type(restart_t),  intent(inout) :: restart
 
    push_sub(restart_end)
 
    if (mpi_grp_is_root(restart%mpi_grp) .and. .not. restart%skip) then
      select case (restart%type)
      case (restart_type_load)
        message(1) = "Info: Finished reading information from '"//trim(restart%dir)//"'."
        call io_rm(trim(restart%pwd)//"/loading", restart%namespace)
      case (restart_type_dump)
        call io_rm(trim(restart%pwd)//"/dumping", restart%namespace)
        message(1) = "Info: Finished writing information to '"//trim(restart%dir)//"'."
      end select
      call messages_info(1, namespace=restart%namespace)
    end if
 
    restart%type = 0
    restart%data_type = 0
    restart%skip = .true.
    safe_deallocate_a(restart%map)
    restart%has_mesh = .false.
    nullify(restart%mc)
 
    pop_sub(restart_end)
  end subroutine restart_end
 
 
  ! ---------------------------------------------------------
  function restart_dir(restart)
    type(restart_t), intent(in) :: restart
    character(len=MAX_PATH_LEN) :: restart_dir
 
    push_sub(restart_dir)
 
    restart_dir = io_workpath(restart%pwd, restart%namespace)
 
    pop_sub(restart_dir)
  end function restart_dir
 
 
  ! ---------------------------------------------------------
  subroutine restart_open_dir(restart, dirname, ierr)
    type(restart_t),  intent(inout) :: restart
    character(len=*), intent(in)    :: dirname
    integer,          intent(out)   :: ierr
 
    push_sub(restart_open_dir)
 
    assert(.not. restart%skip)
 
    ierr = 0
 
    select case (restart%type)
    case (restart_type_dump)
      call restart_mkdir(restart, dirname)
    case (restart_type_load)
      if (.not. loct_dir_exists(trim(restart%dir)//"/"//trim(dirname))) then
        ierr = 1
      end if
    end select
 
    if (ierr == 0) then
      if (index(dirname, '/', .true.) == len_trim(dirname)) then
        restart%pwd = trim(restart%dir)//"/"//dirname(1:len_trim(dirname)-1)
      else
        restart%pwd = trim(restart%dir)//"/"//trim(dirname)
      end if
    end if
 
    pop_sub(restart_open_dir)
  end subroutine restart_open_dir
 
 
  ! ---------------------------------------------------------
  subroutine restart_close_dir(restart)
    type(restart_t),  intent(inout) :: restart
 
    push_sub(restart_close_dir)
 
    assert(.not. restart%skip)
 
    restart%pwd = restart%dir
 
    pop_sub(restart_close_dir)
  end subroutine restart_close_dir
 
 
  ! ---------------------------------------------------------
  subroutine restart_mkdir(restart, dirname)
    type(restart_t),  intent(in) :: restart
    character(len=*), intent(in) :: dirname
 
    push_sub(restart_mkdir)
 
    assert(.not. restart%skip)
 
    assert(restart%type == restart_type_dump)
 
    call io_mkdir(trim(restart%pwd)//"/"//trim(dirname), restart%namespace, parents=.true.)
 
    pop_sub(restart_mkdir)
  end subroutine restart_mkdir
 
 
  ! ---------------------------------------------------------
  subroutine restart_rm(restart, name)
    type(restart_t),  intent(in) :: restart
    character(len=*), intent(in) :: name
 
    assert(.not. restart%skip)
    assert(restart%type == restart_type_dump)
 
    push_sub(restart_rm)
 
    call io_rm(trim(restart%pwd)//"/"//trim(name), restart%namespace)
 
    pop_sub(restart_rm)
  end subroutine restart_rm
 
 
  ! ---------------------------------------------------------
  function restart_open(restart, filename, status, position, silent)
    type(restart_t),            intent(in) :: restart
    character(len=*),           intent(in) :: filename
    character(len=*), optional, intent(in) :: status
    character(len=*), optional, intent(in) :: position
    logical,          optional, intent(in) :: silent
    integer :: restart_open
 
    logical :: die
    character(len=20) :: action, status_
 
    push_sub(restart_open)
 
    assert(.not. restart%skip)
 
    select case (restart%type)
    case (restart_type_dump)
      status_ = 'unknown'
      action = 'write'
      die = .true.
 
    case (restart_type_load)
      status_ = 'old'
      action = 'read'
      die = .false.
 
    case default
      message(1) = "Error in restart_open: illegal restart type"
      call messages_fatal(1)
    end select
 
    if (present(status)) status_ = status
 
    restart_open = io_open(trim(restart%pwd)//"/"//trim(filename), restart%namespace, &
      action=trim(action), status=trim(status_), &
      die=die, position=position, form="formatted", grp=restart%mpi_grp)
 
    if (restart_open == -1 .and. .not. optional_default(silent, .false.)) then
      message(1) = "Unable to open file '"//trim(restart%pwd)//"/"//trim(filename)//"'."
      call messages_warning(1)
    end if
 
    pop_sub(restart_open)
  end function restart_open
 
 
  ! ---------------------------------------------------------
  subroutine restart_write(restart, iunit, lines, nlines, ierr)
    type(restart_t),  intent(in)  :: restart
    integer,          intent(in)  :: iunit
    character(len=*), intent(in)  :: lines(:)
    integer,          intent(in)  :: nlines
    integer,          intent(out) :: ierr
 
    integer :: iline
 
    push_sub(restart_write)
 
    if (iunit /= -1) then
      ierr = 0
      if (mpi_grp_is_root(restart%mpi_grp)) then
        do iline = 1, nlines
          write(iunit,"(a)") trim(lines(iline))
        end do
      end if
    else
      ierr = 1
    end if
 
    pop_sub(restart_write)
  end subroutine restart_write
 
 
  ! ---------------------------------------------------------
  subroutine restart_read(restart, iunit, lines, nlines, ierr)
    type(restart_t),  intent(in)  :: restart
    integer,          intent(in)  :: iunit
    character(len=*), intent(out) :: lines(:)
    integer,          intent(in)  :: nlines
    integer,          intent(out) :: ierr
 
    push_sub(restart_read)
 
    call iopar_read(restart%mpi_grp, iunit, lines, nlines, ierr)
 
    pop_sub(restart_read)
  end subroutine restart_read
 
 
  ! ---------------------------------------------------------
  subroutine restart_close(restart, iunit)
    type(restart_t), intent(in)    :: restart
    integer,         intent(inout) :: iunit
 
    push_sub(restart_close)
 
    if (iunit /= -1) call io_close(iunit, restart%mpi_grp)
 
    pop_sub(restart_close)
  end subroutine restart_close
 
 
  ! ---------------------------------------------------------
  logical pure function restart_skip(restart)
    type(restart_t), intent(in) :: restart
 
    restart_skip = restart%skip .or. restart_has_flag(restart, restart_flag_skip)
 
  end function restart_skip
 
 
  ! ---------------------------------------------------------
  logical pure function restart_has_flag(restart, flag)
    type(restart_t), intent(in) :: restart
    integer,         intent(in) :: flag
 
    restart_has_flag = bitand(info(restart%data_type)%flags, flag) /= 0
 
  end function restart_has_flag
 
 
  ! ---------------------------------------------------------
  logical pure function restart_has_map(restart)
    type(restart_t), intent(in) :: restart
 
    restart_has_map = allocated(restart%map)
 
  end function restart_has_map
 
 
  ! ---------------------------------------------------------
  logical pure function restart_are_basedirs_equal(type1, type2)
    integer, intent(in) :: type1
    integer, intent(in) :: type2
 
    restart_are_basedirs_equal = trim(info(type1)%basedir) == trim(info(type2)%basedir)
 
  end function restart_are_basedirs_equal
 
  integer pure function restart_get_data_type(restart)
    class(restart_t), intent(in) :: restart
 
    restart_get_data_type = restart%data_type
  end function restart_get_data_type
 
 
#include "undef.F90"
#include "real.F90"
#include "restart_inc.F90"
 
#include "undef.F90"
#include "complex.F90"
#include "restart_inc.F90"
 
end module restart_oct_m
 
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: