amg4psblas/mld_dbaseprec_aply.f90

!!$ 
!!$ 
!!$                    MD2P4
!!$    Multilevel Domain Decomposition Parallel Preconditioner Package for PSBLAS
!!$                      for 
!!$              Parallel Sparse BLAS  v2.0
!!$    (C) Copyright 2006 Salvatore Filippone    University of Rome Tor Vergata
!!$                       Alfredo Buttari        University of Rome Tor Vergata
!!$                       Daniela di Serafino    Second University of Naples
!!$                       Pasqua D'Ambra         ICAR-CNR                      
!!$ 
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!!$  
subroutine psb_dbaseprc_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
  !
  !  Compute   Y <-  beta*Y + alpha*K^-1 X 
  !  where K is a a basic preconditioner stored in prec
  ! 

  use psb_base_mod
  use psb_prec_mod, mld_protect_name => psb_dbaseprc_aply

  implicit none 

  type(psb_desc_type),intent(in)      :: desc_data
  type(psb_dbaseprc_type), intent(in) :: prec
  real(kind(0.d0)),intent(inout)      :: x(:), y(:)
  real(kind(0.d0)),intent(in)         :: alpha,beta
  character(len=1)                    :: trans
  real(kind(0.d0)),target             :: work(:)
  integer, intent(out)                :: info

  ! Local variables
  integer :: n_row,n_col, int_err(5), nrow_d
  real(kind(1.d0)), pointer :: ww(:), aux(:), tx(:),ty(:)
  character     ::diagl, diagu
  integer :: ictxt,np,me,i, isz, nrg, err_act
  real(kind(1.d0)) :: t1, t2, t3, t4, t5, t6, t7
  logical,parameter                 :: debug=.false., debugprt=.false.
  character(len=20)   :: name, ch_err

  name='psb_dbaseprc_aply'
  info = 0
  call psb_erractionsave(err_act)

  ictxt = psb_cd_get_context(desc_data)

  call psb_info(ictxt, me, np)

  diagl='U'
  diagu='U'

  select case(trans)
  case('N','n')
  case('T','t','C','c')
  case default
    info=40
    int_err(1)=6
    ch_err(2:2)=trans
    goto 9999
  end select

  select case(prec%iprcparm(p_type_))

  case(noprec_)

    call psb_geaxpby(alpha,x,beta,y,desc_data,info)

  case(diag_)
    
    if (size(work) >= size(x)) then 
      ww => work
    else
      allocate(ww(size(x)),stat=info)
      if (info /= 0) then 
        call psb_errpush(4010,name,a_err='Allocate')
        goto 9999      
      end if
    end if

    n_row = psb_cd_get_local_rows(desc_data)
    ww(1:n_row) = x(1:n_row)*prec%d(1:n_row)
    call psb_geaxpby(alpha,ww,beta,y,desc_data,info)

    if (size(work) < size(x)) then 
      deallocate(ww,stat=info)
      if (info /= 0) then 
        call psb_errpush(4010,name,a_err='Deallocate')
        goto 9999      
      end if
    end if

  case(bjac_)

    call psb_bjac_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
    if(info.ne.0) then
      info=4010
      ch_err='psb_bjac_aply'
      goto 9999
    end if

  case(asm_,ras_,ash_,rash_)

    if (prec%iprcparm(n_ovr_)==0) then 
      ! shortcut: this fixes performance for RAS(0) == BJA
      call psb_bjac_aply(alpha,prec,x,beta,y,desc_data,trans,work,info)
      if(info.ne.0) then
        info=4010
        ch_err='psb_bjacaply'
        goto 9999
      end if

    else
      ! Note: currently trans is unused.
      n_row  = psb_cd_get_local_rows(prec%desc_data)
      n_col  = psb_cd_get_local_cols(prec%desc_data)
      nrow_d = psb_cd_get_local_rows(desc_data)
      isz=max(n_row,N_COL)
      if ((6*isz) <= size(work)) then 
        ww => work(1:isz)
        tx => work(isz+1:2*isz)
        ty => work(2*isz+1:3*isz)
        aux => work(3*isz+1:)
      else if ((4*isz) <= size(work)) then 
        aux => work(1:)
        allocate(ww(isz),tx(isz),ty(isz),stat=info)
        if (info /= 0) then 
          call psb_errpush(4010,name,a_err='Allocate')
          goto 9999      
        end if
      else if ((3*isz) <= size(work)) then 
        ww => work(1:isz)
        tx => work(isz+1:2*isz)
        ty => work(2*isz+1:3*isz)
        allocate(aux(4*isz),stat=info)
        if (info /= 0) then 
          call psb_errpush(4010,name,a_err='Allocate')
          goto 9999      
        end if

      else 
        allocate(ww(isz),tx(isz),ty(isz),&
             &aux(4*isz),stat=info)
        if (info /= 0) then 
          call psb_errpush(4010,name,a_err='Allocate')
          goto 9999      
        end if

      endif

      if (debugprt) write(0,*)' vdiag: ',prec%d(:)
      if (debug) write(0,*) 'Bi-CGSTAB with Additive Schwarz prec' 

      tx(1:nrow_d)     = x(1:nrow_d) 
      tx(nrow_d+1:isz) = dzero

      if (prec%iprcparm(restr_)==psb_halo_) then 
        call psb_halo(tx,prec%desc_data,info,work=aux,data=psb_comm_ext_)
        if(info /=0) then
          info=4010
          ch_err='psb_halo'
          goto 9999
        end if
      else if (prec%iprcparm(restr_) /= psb_none_) then 
        write(0,*) 'Problem in PRC_APLY: Unknown value for restriction ',&
             &prec%iprcparm(restr_)
      end if

      if (prec%iprcparm(iren_)>0) then 
        call dgelp('N',n_row,1,prec%perm,tx,isz,ww,isz,info)
        if(info /=0) then
          info=4010
          ch_err='psb_dgelp'
          goto 9999
        end if
      endif

      call psb_bjac_aply(done,prec,tx,dzero,ty,prec%desc_data,trans,aux,info)
      if(info.ne.0) then
        info=4010
        ch_err='psb_bjac_aply'
        goto 9999
      end if

      if (prec%iprcparm(iren_)>0) then 
        call dgelp('N',n_row,1,prec%invperm,ty,isz,ww,isz,info)
        if(info /=0) then
          info=4010
          ch_err='psb_dgelp'
          goto 9999
        end if
      endif

      select case (prec%iprcparm(prol_)) 

      case(psb_none_) 
        ! Would work anyway, but since it's supposed to do nothing...
        ! call f90_psovrl(ty,prec%desc_data,update=prec%a_restrict)

      case(psb_sum_,psb_avg_) 
        call psb_ovrl(ty,prec%desc_data,info,&
             & update=prec%iprcparm(prol_),work=aux)
        if(info /=0) then
          info=4010
          ch_err='psb_ovrl'
          goto 9999
        end if

      case default
        write(0,*) 'Problem in PRC_APLY: Unknown value for prolongation ',&
             & prec%iprcparm(prol_)
      end select

      call psb_geaxpby(alpha,ty,beta,y,desc_data,info) 


      if ((6*isz) <= size(work)) then 
      else if ((4*isz) <= size(work)) then 
        deallocate(ww,tx,ty)
      else if ((3*isz) <= size(work)) then 
        deallocate(aux)
      else 
        deallocate(ww,aux,tx,ty)
      endif
    end if
  case default
    write(0,*) 'Invalid PRE%PREC ',prec%iprcparm(p_type_),':',&
         & min_prec_,noprec_,diag_,bjac_,&
         & ras_,asm_,ash_,rash_
  end select

  call psb_erractionrestore(err_act)
  return

9999 continue
  call psb_errpush(info,name,i_err=int_err,a_err=ch_err)
  call psb_erractionrestore(err_act)
  if (err_act.eq.psb_act_abort_) then
    call psb_error()
    return
  end if
  return

end subroutine psb_dbaseprc_aply