!!$
!!$
!!$ MLD2P4 version 2.0
!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$ based on PSBLAS (Parallel Sparse BLAS version 3.3)
!!$
!!$ (C) Copyright 2008, 2010, 2012, 2015
!!$
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari CNRS-IRIT, Toulouse
!!$ 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_zaggrmap_bld.f90
!
! Subroutine: mld_zaggrmap_bld
! Version: complex
!
! 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_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.
! 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.
! nlaggr - integer, dimension(:), allocatable.
! nlaggr(i) contains the aggregates held by process i.
! info - integer, output.
! Error code.
!
subroutine mld_zaggrmap_bld(aggr_type,theta,a,desc_a,ilaggr,nlaggr,info)
use psb_base_mod
use mld_z_inner_mod, mld_protect_name => mld_zaggrmap_bld
implicit none
! Arguments
integer(psb_ipk_), intent(in) :: aggr_type
real(psb_dpk_), intent(in) :: theta
type(psb_zspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
integer(psb_ipk_), allocatable, intent(out) :: ilaggr(:),nlaggr(:)
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
type(psb_zspmat_type) :: atmp, atrans
logical :: recovery
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(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 atrans%transp(atmp)
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(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
call psb_erractionrestore(err_act)
return
9999 call psb_error_handler(err_act)
return
end subroutine mld_zaggrmap_bld