amg4psblas/tests/Bcmatch/amg_daggrmat_unsmth_spmm_asb.f90

!   
!   
!                             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 , 2017 
!  
!                        Salvatore Filippone  Cranfield University
!  		      Ambra Abdullahi Hassan University of Rome Tor Vergata
!        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:
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!      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
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!    POSSIBILITY OF SUCH DAMAGE.
!   
!  
! File: mld_daggrmat_nosmth_asb.F90
!
! Subroutine: mld_daggrmat_nosmth_asb
! 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 the piecewise constant interpolation operator corresponding
!  the fine-to-coarse level mapping built by mld_aggrmap_bld.
! 
!  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 mld_dprecinit 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
!
!  For 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:
!    a          -  type(psb_dspmat_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_d_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_dspmat_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_dspmat_type), input/output
!                  The tentative prolongator on input, the computed prolongator on output
!               
!    op_restr    -  type(psb_dspmat_type), output
!                  The restrictor operator; normally, it is the transpose of the prolongator. 
!               
!    info       -  integer, output.
!                  Error code.
!
!
subroutine mld_daggrmat_unsmth_spmm_asb(a,desc_a,ilaggr,nlaggr,parms,ac,op_prol,op_restr,info)
  use psb_base_mod
  use mld_d_inner_mod!, mld_protect_name => mld_daggrmat_unsmth_spmm_asb

  implicit none

  ! Arguments
  type(psb_dspmat_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_dspmat_type), intent(inout)     :: op_prol
  type(psb_dspmat_type), intent(out)       :: ac,op_restr
  integer(psb_ipk_), intent(out)             :: info

  ! Local variables
  integer(psb_ipk_)  :: err_act
  integer(psb_ipk_)  :: ctxt,np,me, icomm, ndx, minfo
  character(len=20)  :: name
  integer(psb_ipk_)  :: ierr(5) 
  type(psb_d_coo_sparse_mat) :: ac_coo, tmpcoo
  type(psb_d_csr_sparse_mat) :: acsr1, acsr2
  type(psb_dspmat_type) :: am3, am4, tmp_prol
  integer(psb_ipk_) :: debug_level, debug_unit
  integer(psb_ipk_) :: nrow, nglob, ncol, ntaggr, nzl, ip, &
       & naggr, nzt, naggrm1, naggrp1, i, k

  name='mld_aggrmat_unsmth_spmm_asb'
  if(psb_get_errstatus().ne.0) return 
  info=psb_success_
  call psb_erractionsave(err_act)


  ctxt = desc_a%get_context()
  icomm = desc_a%get_mpic()
  call psb_info(ctxt, me, np)
  debug_unit  = psb_get_debug_unit()
  debug_level = psb_get_debug_level()
  nglob = desc_a%get_global_rows()
  nrow  = desc_a%get_local_rows()
  ncol  = desc_a%get_local_cols()


  naggr   = nlaggr(me+1)
  ntaggr  = sum(nlaggr)
  naggrm1 = sum(nlaggr(1:me))
  naggrp1 = sum(nlaggr(1:me+1))

  call op_prol%cscnv(info,type='csr',dupl=psb_dupl_add_)
  if (info /= psb_success_) goto 9999

  call op_prol%cp_to(acsr1)

  call tmp_prol%mv_from(acsr1)
  !
  ! Now we have to gather the halo of tmp_prol, and add it to itself
  ! to multiply it by A,
  !
  call psb_sphalo(tmp_prol,desc_a,am4,info,&
       & colcnv=.false.,rowscale=.true.)
  if (info == psb_success_) call psb_rwextd(ncol,tmp_prol,info,b=am4)      
  if (info == psb_success_) call am4%free()
  if(info /= psb_success_) then
    call psb_errpush(psb_err_internal_error_,name,a_err='Halo of tmp_prol')
    goto 9999
  end if

  call psb_spspmm(a,tmp_prol,am3,info)
  if(info /= psb_success_) then
    call psb_errpush(psb_err_from_subroutine_,name,a_err='spspmm 2')
    goto 9999
  end if


  call tmp_prol%mv_to(tmpcoo)
  call tmpcoo%transp()

  nzl = tmpcoo%get_nzeros()
  i=0
  !
  ! Now we have to fix this.  The only rows of B that are correct 
  ! are those corresponding to "local" aggregates, i.e. indices in ilaggr(:)
  !
  do k=1, nzl
    if ((naggrm1 < tmpcoo%ia(k)) .and.(tmpcoo%ia(k) <= naggrp1)) then
      i = i+1
      tmpcoo%val(i) = tmpcoo%val(k)
      tmpcoo%ia(i)  = tmpcoo%ia(k)
      tmpcoo%ja(i)  = tmpcoo%ja(k)
    end if
  end do
  call tmpcoo%set_nzeros(i)
  !  call tmpcoo%trim()
  call op_restr%mv_from(tmpcoo)
  call op_restr%cscnv(info,type='csr',dupl=psb_dupl_add_)

  if (info /= psb_success_) then 
    call psb_errpush(psb_err_from_subroutine_,name,a_err='spcnv op_restr')
    goto 9999
  end if
  if (debug_level >= psb_debug_outer_) &
       & write(debug_unit,*) me,' ',trim(name),&
       & 'starting sphalo/ rwxtd'

  ! op_restr = ((i-wDA)Ptilde)^T
  call psb_sphalo(am3,desc_a,am4,info,&
       & colcnv=.false.,rowscale=.true.)
  if (info == psb_success_) call psb_rwextd(ncol,am3,info,b=am4)      
  if (info == psb_success_) call am4%free()
  if(info /= psb_success_) then
    call psb_errpush(psb_err_internal_error_,name,a_err='Extend am3')
    goto 9999
  end if

  ! op_restr 
  call psb_sphalo(am3,desc_a,am4,info,&
       & colcnv=.false.,rowscale=.true.)
  if (info == psb_success_) call psb_rwextd(ncol,am3,info,b=am4)      
  if (info == psb_success_) call am4%free()
  if(info /= psb_success_) then
    call psb_errpush(psb_err_internal_error_,name,a_err='Extend am3')
    goto 9999
  end if

  if (debug_level >= psb_debug_outer_) &
       & write(debug_unit,*) me,' ',trim(name),&
       & 'starting spspmm 3'
  call psb_spspmm(op_restr,am3,ac,info)
  if (info == psb_success_) call am3%free()
  if (info == psb_success_) call ac%cscnv(info,type='csr',dupl=psb_dupl_add_)
  if (info /= psb_success_) then
    call psb_errpush(psb_err_internal_error_,name,a_err='Build ac = op_restr x am3')
    goto 9999
  end if


  if (debug_level >= psb_debug_outer_) &
       & write(debug_unit,*) me,' ',trim(name),&
       & 'Done smooth_aggregate '

  call psb_erractionrestore(err_act)
  return

9999 call psb_error_handler(err_act)

  return

end subroutine mld_daggrmat_unsmth_spmm_asb