!
!
! MLD2P4 version 2.1
! MultiLevel Domain Decomposition Parallel Preconditioners Package
! based on PSBLAS (Parallel Sparse BLAS version 3.5)
!
! (C) Copyright 2008, 2010, 2012, 2015, 2017
!
! Salvatore Filippone Cranfield University, UK
! Ambra Abdullahi Hassan University of Rome Tor Vergata, IT
! Alfredo Buttari CNRS-IRIT, Toulouse, FR
! Pasqua D'Ambra IAC-CNR, Naples, IT
! Daniela di Serafino University of Campania "L. Vanvitelli", Caserta, IT
!
! 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_zaggrmat_asb.f90
!
! Subroutine: mld_zaggrmat_asb
! Version: complex
!
! 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.
!
! A mapping from the nodes of the adjacency graph of A to the nodes of the
! adjacency graph of A_C has been computed by the mld_aggrmap_bld subroutine.
! The prolongator P_C is built here from this mapping, according to the
! value of p%iprcparm(mld_aggr_prol_), specified by the user through
! mld_zprecinit and mld_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
! mld_z_lev_aggrmat_asb.
!
! Currently four different prolongators are implemented, corresponding to
! four aggregation algorithms:
! 1. un-smoothed aggregation,
! 2. smoothed aggregation,
! 3. "bizarre" aggregation.
! 4. minimum energy
! 1. The non-smoothed aggregation uses as prolongator the piecewise constant
! interpolation operator corresponding to the fine-to-coarse level mapping built
! by mld_aggrmap_bld. This is called tentative prolongator.
! 2. The smoothed aggregation uses as prolongator the operator obtained by applying
! a damped Jacobi smoother to the tentative prolongator.
! 3. The "bizarre" aggregation uses a prolongator proposed by the authors of MLD2P4.
! This prolongator still requires a deep analysis and testing and its use is
! not recommended.
! 4. Minimum energy aggregation: ADD REFERENCE.
!
! For more details see
! M. Brezina and P. Vanek, A black-box iterative solver based on a two-level
! Schwarz method, Computing, 63 (1999), 233-263.
! 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:
! a - type(psb_zspmat_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(mld_z_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(mld_dml_parms), input
! Parameters controlling the choice of algorithm
! ac - type(psb_zspmat_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_zspmat_type), input/output
! The tentative prolongator on input, the computed prolongator on output
!
! op_restr - type(psb_zspmat_type), output
! The restrictor operator; normally, it is the transpose of the prolongator.
!
! info - integer, output.
! Error code.
!
subroutine mld_zaggrmat_asb(a,desc_a,ilaggr,nlaggr,parms,ac,op_prol,op_restr,info)
use psb_base_mod
use mld_base_prec_type
use mld_z_inner_mod, mld_protect_name => mld_zaggrmat_asb
implicit none
! Arguments
type(psb_zspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
integer(psb_ipk_), intent(inout) :: ilaggr(:), nlaggr(:)
type(mld_dml_parms), intent(inout) :: parms
type(psb_zspmat_type), intent(inout) :: ac, op_prol,op_restr
integer(psb_ipk_), intent(out) :: info
! Local variables
type(psb_z_coo_sparse_mat) :: acoo, bcoo
type(psb_z_csr_sparse_mat) :: acsr1
integer(psb_ipk_) :: nzl,ntaggr, err_act
integer(psb_ipk_) :: debug_level, debug_unit
integer(psb_ipk_) :: ictxt,np,me
character(len=20) :: name
name='mld_aggrmat_asb'
if(psb_get_errstatus().ne.0) return
info=psb_success_
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)
select case (parms%aggr_prol)
case (mld_no_smooth_)
call mld_zaggrmat_nosmth_asb(a,desc_a,ilaggr,nlaggr,&
& parms,ac,op_prol,op_restr,info)
case(mld_smooth_prol_)
call mld_zaggrmat_smth_asb(a,desc_a,ilaggr,nlaggr, &
& parms,ac,op_prol,op_restr,info)
case(mld_biz_prol_)
call mld_zaggrmat_biz_asb(a,desc_a,ilaggr,nlaggr, &
& parms,ac,op_prol,op_restr,info)
case(mld_min_energy_)
call mld_zaggrmat_minnrg_asb(a,desc_a,ilaggr,nlaggr, &
& parms,ac,op_prol,op_restr,info)
case default
info = psb_err_internal_error_
call psb_errpush(info,name,a_err='Invalid aggr kind')
goto 9999
end select
if (info /= psb_success_) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='Inner aggrmat asb')
goto 9999
end if
call psb_erractionrestore(err_act)
return
9999 call psb_error_handler(err_act)
return
end subroutine mld_zaggrmat_asb