!!$
!!$
!!$ 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. 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 a 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_kind_), specified by the user through
! mld_dprecinit and mld_dprecset.
!
! Currently three different prolongators are implemented, corresponding to
! three aggregation algorithms:
! 1. raw aggregation,
! 2. smoothed aggregation,
! 3. "bizarre" aggregation.
! 1. The raw 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.
!
! 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.
! ac - type(psb_zspmat_type), output.
! The sparse matrix structure containing the local part of
! the coarse-level matrix.
! desc_ac - type(psb_desc_type), output.
! The communication descriptor of the coarse-level matrix.
! p - type(mld_zbaseprc_type), input/output.
! The base preconditioner data structure containing the local
! part of the base preconditioner to be built.
! info - integer, output.
! Error code.
!
subroutine mld_zaggrmat_asb(a,desc_a,ac,desc_ac,p,info)
use psb_base_mod
use mld_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
type(psb_zspmat_type), intent(out) :: ac
type(psb_desc_type), intent(out) :: desc_ac
type(mld_zbaseprc_type), intent(inout), target :: p
integer, intent(out) :: info
! Local variables
integer :: ictxt,np,me, err_act, icomm
character(len=20) :: name
name='mld_aggrmat_asb'
if(psb_get_errstatus().ne.0) return
info=0
call psb_erractionsave(err_act)
ictxt = psb_cd_get_context(desc_a)
icomm = psb_cd_get_mpic(desc_a)
call psb_info(ictxt, me, np)
select case (p%iprcparm(mld_aggr_kind_))
case (mld_no_smooth_)
call mld_aggrmat_raw_asb(a,desc_a,ac,desc_ac,p,info)
if(info /= 0) then
call psb_errpush(4010,name,a_err='mld_aggrmat_raw_asb')
goto 9999
end if
case(mld_smooth_prol_,mld_biz_prol_)
call mld_aggrmat_smth_asb(a,desc_a,ac,desc_ac,p,info)
if(info /= 0) then
call psb_errpush(4010,name,a_err='mld_aggrmat_smth_asb')
goto 9999
end if
case default
call psb_errpush(4001,name,a_err='Invalid aggr kind')
goto 9999
end select
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_zaggrmat_asb