!!$ !!$ !!$ MLD2P4 version 2.1 !!$ MultiLevel Domain Decomposition Parallel Preconditioners Package !!$ based on PSBLAS (Parallel Sparse BLAS version 3.4) !!$ !!$ (C) Copyright 2008, 2010, 2012, 2015, 2017 !!$ !!$ Salvatore Filippone Cranfield University !!$ Ambra Abdullahi Hassan University of Rome Tor Vergata !!$ Alfredo Buttari CNRS-IRIT, Toulouse !!$ Pasqua D'Ambra ICAR-CNR, Naples !!$ Daniela di Serafino University of Campania "L. Vanvitelli", Caserta !!$ !!$ 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_saggrmap_bld.f90 ! ! Subroutine: mld_saggrmap_bld ! Version: real ! ! This routine builds a mapping from the row indices of the fine-level matrix ! to the row indices of the coarse-level matrix, according to a decoupled ! aggregation algorithm. This mapping will be used by mld_aggrmat_asb to ! build the coarse-level matrix. ! ! The aggregation algorithm is a parallel version of that described in ! * M. Brezina and P. Vanek, A black-box iterative solver based on a ! two-level Schwarz method, Computing, 63 (1999), 233-263. ! * P. Vanek, J. Mandel and M. Brezina, Algebraic Multigrid by Smoothed ! Aggregation for Second and Fourth Order Elliptic Problems, Computing, 56 ! (1996), 179-196. ! For more details see ! P. D'Ambra, D. di Serafino and S. Filippone, On the development of ! PSBLAS-based parallel two-level Schwarz preconditioners, Appl. Num. Math. ! 57 (2007), 1181-1196. ! ! ! Arguments: ! aggr_type - integer, input. ! The scalar used to identify the aggregation algorithm. ! theta - real, input. ! The aggregation threshold used in the aggregation algorithm. ! 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. ! ilaggr - integer, dimension(:), allocatable. ! 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 on exit the indices ! will be shifted so as to make sure the ranges on the various processes do not ! overlap. ! nlaggr - integer, dimension(:), allocatable. ! nlaggr(i) contains the aggregates held by process i. ! op_prol - type(psb_sspmat_type). ! The tentative prolongator, based on ilaggr. ! ! info - integer, output. ! Error code. ! subroutine mld_saggrmap_bld(aggr_type,iorder,theta,a,desc_a,ilaggr,nlaggr,op_prol,info) use psb_base_mod use mld_s_inner_mod, mld_protect_name => mld_saggrmap_bld implicit none ! Arguments integer(psb_ipk_), intent(in) :: iorder integer(psb_ipk_), intent(in) :: aggr_type real(psb_spk_), intent(in) :: theta type(psb_sspmat_type), intent(in) :: a type(psb_desc_type), intent(in) :: desc_a integer(psb_ipk_), allocatable, intent(out) :: ilaggr(:),nlaggr(:) type(psb_sspmat_type), intent(out) :: op_prol integer(psb_ipk_), intent(out) :: info ! Local variables integer(psb_ipk_), allocatable :: ils(:), neigh(:) integer(psb_ipk_) :: icnt,nlp,k,n,ia,isz,nr, naggr,i,j,m,naggrm1, naggrp1, ntaggr type(psb_sspmat_type) :: atmp, atrans type(psb_s_coo_sparse_mat) :: tmpcoo integer(psb_ipk_) :: debug_level, debug_unit,err_act integer(psb_ipk_) :: ictxt,np,me integer(psb_ipk_) :: nrow, ncol, n_ne character(len=20) :: name, ch_err if(psb_get_errstatus() /= 0) return info=psb_success_ name = 'mld_aggrmap_bld' call psb_erractionsave(err_act) debug_unit = psb_get_debug_unit() debug_level = psb_get_debug_level() ! ictxt=desc_a%get_context() call psb_info(ictxt,me,np) nrow = desc_a%get_local_rows() ncol = desc_a%get_local_cols() select case (aggr_type) case (mld_dec_aggr_) call mld_dec_map_bld(iorder,theta,a,desc_a,nlaggr,ilaggr,info) case (mld_sym_dec_aggr_) nr = a%get_nrows() call a%csclip(atmp,info,imax=nr,jmax=nr,& & rscale=.false.,cscale=.false.) call atmp%set_nrows(nr) call atmp%set_ncols(nr) if (info == psb_success_) call atmp%transp(atrans) if (info == psb_success_) call atrans%cscnv(info,type='COO') if (info == psb_success_) call psb_rwextd(nr,atmp,info,b=atrans,rowscale=.false.) call atmp%set_nrows(nr) call atmp%set_ncols(nr) if (info == psb_success_) call atrans%free() if (info == psb_success_) call atmp%cscnv(info,type='CSR') if (info == psb_success_) call mld_dec_map_bld(iorder,theta,atmp,desc_a,nlaggr,ilaggr,info) if (info == psb_success_) call atmp%free() case default info = -1 call psb_errpush(psb_err_input_value_invalid_i_,name,& & i_err=(/ione,aggr_type,izero,izero,izero/)) goto 9999 end select if (info /= psb_success_) then info=psb_err_internal_error_ call psb_errpush(info,name,a_err='dec_map_bld') goto 9999 end if naggr = nlaggr(me+1) ntaggr = sum(nlaggr) naggrm1 = sum(nlaggr(1:me)) naggrp1 = sum(nlaggr(1:me+1)) ilaggr(1:nrow) = ilaggr(1:nrow) + naggrm1 call psb_halo(ilaggr,desc_a,info) if (info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='psb_halo') goto 9999 end if call tmpcoo%allocate(ncol,ntaggr,ncol) do i=1,ncol tmpcoo%val(i) = sone tmpcoo%ia(i) = i tmpcoo%ja(i) = ilaggr(i) end do call tmpcoo%set_nzeros(ncol) call tmpcoo%set_dupl(psb_dupl_add_) call tmpcoo%set_sorted() ! At this point this is in row-major call op_prol%mv_from(tmpcoo) call psb_erractionrestore(err_act) return 9999 call psb_error_handler(err_act) return end subroutine mld_saggrmap_bld