! ! ! AMG4PSBLAS version 1.0 ! Algebraic Multigrid Package ! based on PSBLAS (Parallel Sparse BLAS version 3.5) ! ! (C) Copyright 2020 ! ! Salvatore Filippone ! Pasqua D'Ambra ! Fabio Durastante ! ! 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 AMG4PSBLAS 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 AMG4PSBLAS 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: amg_saggrmat_smth_bld.F90 ! ! Subroutine: amg_saggrmat_smth_bld ! Version: real ! ! This routine builds a coarse-level matrix A_C from a fine-level matrix A ! by using the Galerkin approach, i.e. ! ! A_C = P_C^T A P_C, ! ! where P_C is a prolongator from the coarse level to the fine one. ! ! The prolongator P_C is built according to a smoothed aggregation algorithm, ! i.e. it is obtained by applying a damped Jacobi smoother to the piecewise ! constant interpolation operator P corresponding to the fine-to-coarse level ! mapping built by the amg_aggrmap_bld subroutine: ! ! P_C = (I - omega*D^(-1)A) * P, ! ! where D is the diagonal matrix with main diagonal equal to the main diagonal ! of A, and omega is a suitable smoothing parameter. An estimate of the spectral ! radius of D^(-1)A, to be used in the computation of omega, is provided, ! according to the value of p%parms%aggr_omega_alg, specified by the user ! through amg_sprecinit and amg_zprecset. ! ! The coarse-level matrix A_C is distributed among the parallel processes or ! replicated on each of them, according to the value of p%parms%coarse_mat, ! specified by the user through amg_sprecinit and amg_zprecset. ! On output from this routine the entries of AC, op_prol, op_restr ! are still in "global numbering" mode; this is fixed in the calling routine ! aggregator%mat_bld. ! ! ! Arguments: ! a - type(psb_sspmat_type), input. ! The sparse matrix structure containing the local part of ! the fine-level matrix. ! desc_a - type(psb_desc_type), input. ! The communication descriptor of the fine-level matrix. ! p - type(amg_s_onelev_type), input/output. ! The 'one-level' data structure that will contain the local ! part of the matrix to be built as well as the information ! concerning the prolongator and its transpose. ! parms - type(amg_sml_parms), input ! Parameters controlling the choice of algorithm ! ac - type(psb_sspmat_type), output ! The coarse matrix on output ! ! ilaggr - integer, dimension(:), input ! The mapping between the row indices of the coarse-level ! matrix and the row indices of the fine-level matrix. ! ilaggr(i)=j means that node i in the adjacency graph ! of the fine-level matrix is mapped onto node j in the ! adjacency graph of the coarse-level matrix. Note that the indices ! are assumed to be shifted so as to make sure the ranges on ! the various processes do not overlap. ! nlaggr - integer, dimension(:) input ! nlaggr(i) contains the aggregates held by process i. ! op_prol - type(psb_sspmat_type), input/output ! The tentative prolongator on input, the computed prolongator on output ! ! op_restr - type(psb_sspmat_type), output ! The restrictor operator; normally, it is the transpose of the prolongator. ! ! info - integer, output. ! Error code. ! subroutine amg_saggrmat_smth_bld(a,desc_a,ilaggr,nlaggr,parms,& & ac,desc_ac,op_prol,op_restr,t_prol,info) use psb_base_mod use amg_base_prec_type use amg_s_inner_mod, amg_protect_name => amg_saggrmat_smth_bld use amg_s_base_aggregator_mod implicit none ! Arguments type(psb_sspmat_type), intent(in) :: a type(psb_desc_type), intent(inout) :: desc_a integer(psb_lpk_), intent(inout) :: ilaggr(:), nlaggr(:) type(amg_sml_parms), intent(inout) :: parms type(psb_sspmat_type), intent(out) :: op_prol,ac,op_restr type(psb_lsspmat_type), intent(inout) :: t_prol type(psb_desc_type), intent(inout) :: desc_ac integer(psb_ipk_), intent(out) :: info ! Local variables integer(psb_lpk_) :: nrow, nglob, ncol, ntaggr, ip, & & naggr, nzl,naggrm1,naggrp1, i, j, k, jd, icolF, nrw integer(psb_ipk_) :: inaggr, nzlp integer(psb_ipk_) :: ictxt, np, me character(len=20) :: name type(psb_ls_coo_sparse_mat) :: tmpcoo type(psb_s_coo_sparse_mat) :: coo_prol, coo_restr type(psb_s_csr_sparse_mat) :: acsr1, acsrf, csr_prol, acsr real(psb_spk_), allocatable :: adiag(:) real(psb_spk_), allocatable :: arwsum(:) integer(psb_ipk_) :: ierr(5) logical :: filter_mat integer(psb_ipk_) :: debug_level, debug_unit, err_act integer(psb_ipk_), parameter :: ncmax=16 real(psb_spk_) :: anorm, omega, tmp, dg, theta logical, parameter :: debug_new=.false. character(len=80) :: filename name='amg_aggrmat_smth_bld' info=psb_success_ call psb_erractionsave(err_act) if (psb_errstatus_fatal()) then info = psb_err_internal_error_; goto 9999 end if debug_unit = psb_get_debug_unit() debug_level = psb_get_debug_level() ictxt = desc_a%get_context() call psb_info(ictxt, me, np) nglob = desc_a%get_global_rows() nrow = desc_a%get_local_rows() ncol = desc_a%get_local_cols() theta = parms%aggr_thresh naggr = nlaggr(me+1) ntaggr = sum(nlaggr) naggrm1 = sum(nlaggr(1:me)) naggrp1 = sum(nlaggr(1:me+1)) filter_mat = (parms%aggr_filter == amg_filter_mat_) ! ! naggr: number of local aggregates ! nrow: local rows. ! ! Get the diagonal D adiag = a%get_diag(info) if (info == psb_success_) & & call psb_realloc(ncol,adiag,info) if (info == psb_success_) & & call psb_halo(adiag,desc_a,info) if (info == psb_success_) call a%cp_to(acsr) if(info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='sp_getdiag') goto 9999 end if if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),& & ' Initial copies done.' call acsr%cp_to_fmt(acsrf,info) if (filter_mat) then ! ! Build the filtered matrix Af from A ! do i=1, nrow tmp = szero jd = -1 do j=acsrf%irp(i),acsrf%irp(i+1)-1 if (acsrf%ja(j) == i) jd = j if (abs(acsrf%val(j)) < theta*sqrt(abs(adiag(i)*adiag(acsrf%ja(j))))) then tmp=tmp+acsrf%val(j) acsrf%val(j)=szero endif enddo if (jd == -1) then write(0,*) 'Wrong input: we need the diagonal!!!!', i else acsrf%val(jd)=acsrf%val(jd)-tmp end if enddo ! Take out zeroed terms call acsrf%clean_zeros(info) end if do i=1,size(adiag) if (adiag(i) /= szero) then adiag(i) = sone / adiag(i) else adiag(i) = sone end if end do if (parms%aggr_omega_alg == amg_eig_est_) then if (parms%aggr_eig == amg_max_norm_) then allocate(arwsum(nrow)) call acsr%arwsum(arwsum) anorm = maxval(abs(adiag(1:nrow)*arwsum(1:nrow))) call psb_amx(ictxt,anorm) omega = 4.d0/(3.d0*anorm) parms%aggr_omega_val = omega else info = psb_err_internal_error_ call psb_errpush(info,name,a_err='invalid amg_aggr_eig_') goto 9999 end if else if (parms%aggr_omega_alg == amg_user_choice_) then omega = parms%aggr_omega_val else if (parms%aggr_omega_alg /= amg_user_choice_) then info = psb_err_internal_error_ call psb_errpush(info,name,a_err='invalid amg_aggr_omega_alg_') goto 9999 end if call acsrf%scal(adiag,info) if (info /= psb_success_) goto 9999 call t_prol%mv_to(tmpcoo) inaggr = naggr call psb_cdall(ictxt,desc_ac,info,nl=inaggr) nzlp = tmpcoo%get_nzeros() call desc_ac%indxmap%g2lip_ins(tmpcoo%ja(1:nzlp),info) call tmpcoo%set_ncols(desc_ac%get_local_cols()) call tmpcoo%mv_to_ifmt(csr_prol,info) call psb_cdasb(desc_ac,info) call psb_cd_reinit(desc_ac,info) ! ! Build the smoothed prolongator using either A or Af ! acsr1 = (I-w*D*A) Prol acsr1 = (I-w*D*Af) Prol ! This is always done through the variable acsrf which ! is a bit less readable, but saves space and one matrix copy ! call omega_smooth(omega,acsrf) call psb_par_spspmm(acsrf,desc_a,csr_prol,acsr1,desc_ac,info) if(info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='spspmm 1') goto 9999 end if if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),& & 'Done SPSPMM 1' nzl = acsr1%get_nzeros() call acsr1%mv_to_coo(coo_prol,info) call amg_ptap_bld(acsr,desc_a,nlaggr,parms,ac,& & coo_prol,desc_ac,coo_restr,info) call op_prol%mv_from(coo_prol) call op_restr%mv_from(coo_restr) if (debug_level >= psb_debug_outer_) & & write(debug_unit,*) me,' ',trim(name),& & 'Done smooth_aggregate ' call psb_erractionrestore(err_act) return 9999 continue call psb_errpush(info,name) call psb_error_handler(err_act) return contains subroutine omega_smooth(omega,acsr) implicit none real(psb_spk_),intent(in) :: omega type(psb_s_csr_sparse_mat), intent(inout) :: acsr ! integer(psb_lpk_) :: i,j do i=1,acsr%get_nrows() do j=acsr%irp(i),acsr%irp(i+1)-1 if (acsr%ja(j) == i) then acsr%val(j) = sone - omega*acsr%val(j) else acsr%val(j) = - omega*acsr%val(j) end if end do end do end subroutine omega_smooth end subroutine amg_saggrmat_smth_bld