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amg4psblas/mlprec/mld_ddiag_bld.f90

162 lines
5.2 KiB
Fortran

!!$
!!$
!!$ MLD2P4
!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$ based on PSBLAS (Parallel Sparse BLAS v.2.0)
!!$
!!$ (C) Copyright 2007 Alfredo Buttari University of Rome Tor Vergata
!!$ Pasqua D'Ambra ICAR-CNR, Naples
!!$ Daniela di Serafino Second University of Naples
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$
!!$ Redistribution and use in source and binary forms, with or without
!!$ modification, are permitted provided that the following conditions
!!$ are met:
!!$ 1. Redistributions of source code must retain the above copyright
!!$ notice, this list of conditions and the following disclaimer.
!!$ 2. Redistributions in binary form must reproduce the above copyright
!!$ notice, this list of conditions, and the following disclaimer in the
!!$ documentation and/or other materials provided with the distribution.
!!$ 3. The name of the MLD2P4 group or the names of its contributors may
!!$ not be used to endorse or promote products derived from this
!!$ software without specific written permission.
!!$
!!$ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
!!$ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
!!$ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
!!$ PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE MLD2P4 GROUP OR ITS CONTRIBUTORS
!!$ BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
!!$ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
!!$ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
!!$ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
!!$ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
!!$ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
!!$ POSSIBILITY OF SUCH DAMAGE.
!!$
!!$
! File: mld_ddiag_bld.f90
!
! Subroutine: mld_ddiag_bld
! Version: real
!
! This routine builds the diagonal preconditioner corresponding to a given
! sparse matrix A.
!
!
! Arguments:
! a - type(psb_dspmat_type), input.
! The sparse matrix structure containing the local part of the
! matrix A to be preconditioned.
! desc_a - type(psb_desc_type), input.
! The communication descriptor associated to the sparse matrix A.
! p - type(mld_dbaseprc_type), input/output.
! The 'base preconditioner' data structure containing the local
! part of the diagonal preconditioner.
! info - integer, output.
! Error code.
!
subroutine mld_ddiag_bld(a,desc_a,p,upd,info)
use psb_base_mod
use mld_prec_mod, mld_protect_name => mld_ddiag_bld
Implicit None
! Arguments
type(psb_dspmat_type), target :: a
type(psb_desc_type), intent(in) :: desc_a
type(mld_dbaseprc_type),intent(inout) :: p
character, intent(in) :: upd
integer, intent(out) :: info
! Local variables
Integer :: err, n_row, n_col,I,j,k,ictxt,&
& me,np,mglob,lw, err_act
integer :: debug_level, debug_unit
character(len=20) :: name, ch_err
if(psb_get_errstatus().ne.0) return
info=0
err=0
call psb_erractionsave(err_act)
debug_unit = psb_get_debug_unit()
debug_level = psb_get_debug_level()
name = 'mld_ddiag_bld'
info = 0
ictxt = psb_cd_get_context(desc_a)
n_row = psb_cd_get_local_rows(desc_a)
n_col = psb_cd_get_local_cols(desc_a)
mglob = psb_cd_get_global_rows(desc_a)
call psb_info(ictxt, me, np)
if (debug_level >= psb_debug_outer_)&
& write(debug_unit,*) me,' ',trim(name),' Enter'
call psb_realloc(n_col,p%d,info)
if (info /= 0) then
call psb_errpush(4010,name,a_err='psb_realloc')
goto 9999
end if
!
! Retrieve the diagonal entries of the matrix A
!
call psb_sp_getdiag(a,p%d,info)
if(info /= 0) then
info=4010
ch_err='psb_sp_getdiag'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end if
!
! Copy into p%desc_data the descriptor associated to A
!
call psb_cdcpy(desc_a,p%desc_Data,info)
if (info /= 0) then
call psb_errpush(4010,name,a_err='psb_cdcpy')
goto 9999
end if
!
! The i-th diagonal entry of the preconditioner is set to one if the
! corresponding entry a_ii of the sparse matrix A is zero; otherwise
! it is set to one/a_ii
!
do i=1,n_row
if (p%d(i) == dzero) then
p%d(i) = done
else
p%d(i) = done/p%d(i)
endif
end do
if (a%pl(1) /= 0) then
!
! Apply the same row permutation as in the sparse matrix A
!
call psb_gelp('n',a%pl,p%d,info)
if(info /= 0) then
info=4010
ch_err='psb_gelp'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end if
endif
if (debug_level >= psb_debug_outer_) &
& write(debug_unit,*) me,' ',trim(name),'Done'
call psb_erractionrestore(err_act)
return
9999 continue
call psb_erractionrestore(err_act)
if (err_act.eq.psb_act_abort_) then
call psb_error()
return
end if
return
end subroutine mld_ddiag_bld