!!$ !!$ !!$ MLD2P4 version 1.0 !!$ MultiLevel Domain Decomposition Parallel Preconditioners Package !!$ based on PSBLAS (Parallel Sparse BLAS version 2.2) !!$ !!$ (C) Copyright 2008 !!$ !!$ 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. 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File: mld_dcoarse_bld.f90 ! ! Subroutine: mld_dcoarse_bld ! Version: real ! ! This routine builds the preconditioner corresponding to the current ! level of the multilevel preconditioner. The routine first builds the ! (coarse) matrix associated to the current level from the (fine) matrix ! associated to the previous level, then builds the related base preconditioner. ! Note that this routine is only ever called on levels >= 2. ! ! ! Arguments: ! a - type(psb_dspmat_type). ! The sparse matrix structure containing the local part of the ! matrix to be preconditioned. ! desc_a - type(psb_desc_type), input. ! The communication descriptor of a. ! p - type(mld_donelev_type), input/output. ! The preconditioner data structure containing the local ! part of the one-level preconditioner to be built. ! 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_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