!!$
!!$
!!$ MLD2P4 version 1.1
!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$ based on PSBLAS (Parallel Sparse BLAS version 2.3.1)
!!$
!!$ (C) Copyright 2008,2009
!!$
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari University of Rome Tor Vergata
!!$ Pasqua D'Ambra ICAR-CNR, Naples
!!$ Daniela di Serafino Second University of Naples
!!$
!!$ 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_dcoarse_bld.f90
!
! Subroutine: mld_dcoarse_bld
! Version: real
!
! This routine builds the matrix associated to the current level of the
! multilevel preconditioner from the matrix associated to the previous level,
! by using a smoothed aggregation technique (therefore, it also builds the
! prolongation and restriction operators mapping the current level to the
! previous one and vice versa). Then the routine builds the base preconditioner
! at the current level.
! The current level is regarded as the coarse one, while the previous as
! the fine one. This is in agreement with the fact that the routine is called,
! by mld_mlprec_bld, only on levels >=2.
!
!
! Arguments:
! a - type(psb_dspmat_type).
! The sparse matrix structure containing the local part of the
! fine-level matrix.
! desc_a - type(psb_desc_type), input.
! The communication descriptor of a.
! p - type(mld_donelev_type), input/output.
! The 'one-level' data structure containing the local part
! of the base preconditioner to be built as well as
! information concerning the prolongator and its transpose.
! info - integer, output.
! Error code.
!
subroutine mld_dcoarse_bld(a,desc_a,p,info)
use psb_base_mod
use mld_inner_mod, mld_protect_name => mld_dcoarse_bld
implicit none
! Arguments
type(psb_dspmat_type), intent(in), target :: a
type(psb_desc_type), intent(in), target :: desc_a
type(mld_donelev_type), intent(inout),target :: p
integer, intent(out) :: info
! Local variables
type(psb_desc_type) :: desc_ac
type(psb_dspmat_type) :: ac
character(len=20) :: name
integer :: ictxt, np, me, err_act
integer, allocatable :: ilaggr(:), nlaggr(:)
name='mld_dcoarse_bld'
if (psb_get_errstatus().ne.0) return
call psb_erractionsave(err_act)
info = 0
ictxt = psb_cd_get_context(desc_a)
call psb_info(ictxt,me,np)
if (.not.allocated(p%iprcparm)) then
info = 2222
call psb_errpush(info,name)
goto 9999
endif
call mld_check_def(p%iprcparm(mld_ml_type_),'Multilevel type',&
& mld_mult_ml_,is_legal_ml_type)
call mld_check_def(p%iprcparm(mld_aggr_alg_),'Aggregation',&
& mld_dec_aggr_,is_legal_ml_aggr_alg)
call mld_check_def(p%iprcparm(mld_aggr_kind_),'Smoother',&
& mld_smooth_prol_,is_legal_ml_aggr_kind)
call mld_check_def(p%iprcparm(mld_coarse_mat_),'Coarse matrix',&
& mld_distr_mat_,is_legal_ml_coarse_mat)
call mld_check_def(p%iprcparm(mld_aggr_filter_),'Use filtered matrix',&
& mld_no_filter_mat_,is_legal_aggr_filter)
call mld_check_def(p%iprcparm(mld_smoother_pos_),'smooth_pos',&
& mld_pre_smooth_,is_legal_ml_smooth_pos)
call mld_check_def(p%iprcparm(mld_aggr_omega_alg_),'Omega Alg.',&
& mld_eig_est_,is_legal_ml_aggr_omega_alg)
call mld_check_def(p%iprcparm(mld_aggr_eig_),'Eigenvalue estimate',&
& mld_max_norm_,is_legal_ml_aggr_eig)
call mld_check_def(p%rprcparm(mld_aggr_omega_val_),'Omega',dzero,is_legal_omega)
call mld_check_def(p%rprcparm(mld_aggr_thresh_),'Aggr_Thresh',dzero,is_legal_aggr_thrs)
!
! Build a mapping between the row indices of the fine-level matrix
! and the row indices of the coarse-level matrix, according to a decoupled
! aggregation algorithm. This also defines a tentative prolongator from
! the coarse to the fine level.
!
call mld_aggrmap_bld(p%iprcparm(mld_aggr_alg_),p%rprcparm(mld_aggr_thresh_),&
& a,desc_a,ilaggr,nlaggr,info)
if(info /= 0) then
call psb_errpush(4010,name,a_err='mld_aggrmap_bld')
goto 9999
end if
!
! Build the coarse-level matrix from the fine-level one, starting from
! the mapping defined by mld_aggrmap_bld and applying the aggregation
! algorithm specified by p%iprcparm(mld_aggr_kind_)
!
call mld_aggrmat_asb(a,desc_a,ilaggr,nlaggr,p,info)
if(info /= 0) then
call psb_errpush(4010,name,a_err='mld_aggrmat_asb')
goto 9999
end if
!
! Fix the base_a and base_desc pointers for handling of residuals.
! This is correct because this routine is only called at levels >=2.
!
p%base_a => p%ac
p%base_desc => p%desc_ac
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_dcoarse_bld