subspace.F90

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!! Copyright (C) 2002-2006 M. Marques, A. Castro, A. Rubio, G. Bertsch
!!
!! 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 subspace_oct_m
  use accel_oct_m
  use accel_blas_oct_m
  use batch_oct_m
  use batch_ops_oct_m
  use blas_oct_m
  use blacs_oct_m
  use blacs_proc_grid_oct_m
  use debug_oct_m
#ifdef HAVE_ELPA
  use elpa
#endif
  use global_oct_m
  use hamiltonian_elec_oct_m
  use hardware_oct_m
  use, intrinsic :: iso_fortran_env
  use lalg_basic_oct_m
  use lalg_adv_oct_m
  use math_oct_m
  use mesh_oct_m
  use mesh_batch_oct_m
  use messages_oct_m
  use namespace_oct_m
  use parser_oct_m
  use pblas_oct_m
  use profiling_oct_m
  use scalapack_oct_m
  use states_abst_oct_m
  use states_elec_oct_m
  use states_elec_calc_oct_m
  use states_elec_parallel_oct_m
  use types_oct_m
  use varinfo_oct_m
  use wfs_elec_oct_m
 
  implicit none
 
  private
 
  public ::               &
    subspace_t,           &
    dsubspace_diag,       &
    zsubspace_diag,       &
    dsubspace_diag_hamiltonian, &
    zsubspace_diag_hamiltonian
 
  type subspace_t
    private
    integer :: method
  contains
    procedure :: init => subspace_init 
  end type subspace_t
 
 
contains
 
  subroutine subspace_init(this, namespace, st)
    class(subspace_t),    intent(out) :: this
    type(namespace_t),    intent(in)  :: namespace
    type(states_elec_t),  intent(in)  :: st
 
    integer :: default
 
    push_sub(subspace_init)
 
    !%Variable SubspaceDiagonalization
    !%Type integer
    !%Default standard
    !%Section SCF::Eigensolver
    !%Description
    !% Selects the method to perform subspace diagonalization. The
    !% default is <tt>standard</tt>, unless states parallelization is used,
    !% when the default is <tt>scalapack</tt>.
    !% Note that this variable is not parsed in the case of the evolution eigensolver.
    !%Option none 0
    !% No subspace diagonalization. WARNING: this will generally give incorrect results.
    !%Option standard 1
    !% The standard routine. Can be used with domain parallelization but not
    !% state parallelization.
    !%Option scalapack 3
    !% State-parallelized version using ScaLAPACK. (Requires that
    !% Octopus was compiled with ScaLAPACK support.)
    !%End
 
    default = option__subspacediagonalization__standard
 
#ifdef HAVE_SCALAPACK
    if (st%parallel_in_states) default = option__subspacediagonalization__scalapack
#endif
 
    call parse_variable(namespace, 'SubspaceDiagonalization', default, this%method)
 
    if (.not. varinfo_valid_option('SubspaceDiagonalization', this%method)) then
      call messages_input_error(namespace, 'SubspaceDiagonalization')
    end if
 
    call messages_print_var_option('SubspaceDiagonalization', this%method, namespace=namespace)
 
    ! some checks for ingenious users
    if (this%method == option__subspacediagonalization__scalapack) then
#ifndef HAVE_MPI
      message(1) = 'The scalapack subspace diagonalization can only be used with MPI parallelization.'
      call messages_fatal(1, only_root_writes = .true., namespace=namespace)
#else
#ifndef HAVE_SCALAPACK
      message(1) = 'The scalapack subspace diagonalization requires scalapack.'
      call messages_fatal(1, only_root_writes = .true., namespace=namespace)
#endif
      if (st%dom_st_mpi_grp%size == 1) then
        message(1) = 'The scalapack subspace diagonalization is designed to be used with domain or state parallelization.'
        call messages_warning(1, namespace=namespace)
      end if
 
      if (st%d%kpt%parallel) then
        message(1) = 'Currently the scalapack subspace diagonalization does not use k-point parallelization.'
        call messages_warning(1, namespace=namespace)
      end if
#endif
    end if
 
    pop_sub(subspace_init)
  end subroutine subspace_init
 
#include "undef.F90"
#include "real.F90"
#include "subspace_inc.F90"
 
#include "undef.F90"
#include "complex.F90"
#include "subspace_inc.F90"
 
end module subspace_oct_m
 
!! Local Variables:
!! mode: f90
!! coding: utf-8
!! End: