quantum-espresso/Modules/set_para_diag.f90

98 lines
3.6 KiB
Fortran

!
! Copyright (C) 2021 Quantum ESPRESSO Fondation
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!----------------------------------------------------------------------------
SUBROUTINE set_para_diag( nbnd, use_para_diag )
!-----------------------------------------------------------------------------
!! Sets up the communicator used for parallel diagonalization in LAXlib.
!! Merges previous code executed at startup with function "check_para_diag".
!! To be called after the initialization of variables is completed and
!! the dimension of matrices to be diagonalized is known
!
USE io_global, ONLY : stdout, ionode
USE mp_bands, ONLY : intra_bgrp_comm, inter_bgrp_comm
USE mp_pools, ONLY : intra_pool_comm
USE mp_world, ONLY : world_comm
USE mp_exx, ONLY : negrp
USE command_line_options, ONLY : ndiag_
IMPLICIT NONE
INCLUDE 'laxlib.fh'
INTEGER, INTENT(IN) :: nbnd
!! dimension of matrices to be diagonalized (number of bands)
LOGICAL, INTENT(INOUT) :: use_para_diag
!! true if parallel linear algebra is to be used
!
LOGICAL, SAVE :: first = .TRUE.
LOGICAL :: do_diag_in_band_group = .TRUE.
INTEGER :: np_ortho(2), ortho_parent_comm
IF( .NOT. first ) RETURN
first = .FALSE.
!
IF( negrp > 1 .OR. do_diag_in_band_group ) THEN
! one diag group per bgrp with strict hierarchy: POOL > BAND > DIAG
! if using exx groups from mp_exx, always use this diag method
CALL laxlib_start ( ndiag_, intra_bgrp_comm, .TRUE. )
ELSE
! one diag group per pool ( individual k-point level )
! with band group and diag group both being children of POOL comm
CALL laxlib_start ( ndiag_, intra_pool_comm, .FALSE. )
END IF
CALL set_mpi_comm_4_solvers( intra_pool_comm, intra_bgrp_comm, &
inter_bgrp_comm )
!
#if defined(__MPI)
CALL laxlib_getval( np_ortho = np_ortho, ortho_parent_comm = ortho_parent_comm )
!
IF( np_ortho(1) > nbnd ) &
CALL errore ('set_para_diag', 'Too few bands for required ndiag',nbnd)
!
use_para_diag = ( np_ortho( 1 ) > 1 .AND. np_ortho( 2 ) > 1 )
!
IF ( ionode ) THEN
!
WRITE( stdout, '(5X,"Subspace diagonalization in iterative solution ",&
& "of the eigenvalue problem:")' )
IF ( use_para_diag ) THEN
IF (ortho_parent_comm == intra_pool_comm) THEN
WRITE( stdout, '(5X,"one sub-group per k-point group (pool) will be used")' )
ELSE IF (ortho_parent_comm == intra_bgrp_comm) THEN
WRITE( stdout, '(5X,"one sub-group per band group will be used")' )
ELSE
CALL errore( 'setup','Unexpected sub-group communicator ', 1 )
END IF
#if defined(__ELPA) || defined(__ELPA_2015) || defined(__ELPA_2016)
WRITE( stdout, '(5X,"ELPA distributed-memory algorithm ", &
& "(size of sub-group: ", I2, "*", I3, " procs)",/)') &
np_ortho(1), np_ortho(2)
#elif defined(__SCALAPACK)
WRITE( stdout, '(5X,"scalapack distributed-memory algorithm ", &
& "(size of sub-group: ", I2, "*", I3, " procs)",/)') &
np_ortho(1), np_ortho(2)
#else
WRITE( stdout, '(5X,"custom distributed-memory algorithm ", &
& "(size of sub-group: ", I2, "*", I3, " procs)",/)') &
np_ortho(1), np_ortho(2)
#endif
ELSE
WRITE( stdout, '(5X,"a serial algorithm will be used",/)' )
END IF
!
END IF
!
#else
!
use_para_diag = .FALSE.
!
#endif
!
RETURN
END SUBROUTINE set_para_diag