!!$ 
!!$ 
!!$                    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                      
!!$ 
!!$  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 MD2P4 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 MD2P4 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.
!!$ 
!!$  
subroutine psb_dprecbld(a,desc_a,p,info,upd)

  use psb_base_mod
  use psb_prec_mod, protect => psb_dprecbld
  Implicit None

  type(psb_dspmat_type), target           :: a
  type(psb_desc_type), intent(in), target :: desc_a
  type(psb_dprec_type),intent(inout)      :: p
  integer, intent(out)                    :: info
  character, intent(in), optional         :: upd

  ! Local scalars
  Integer      :: err,i,j,k,ictxt, me,np,lw, err_act
  integer      :: int_err(5)
  character    :: iupd

  logical, parameter :: debug=.false., dump_aggr=.false.
  integer,parameter  :: iroot=0,iout=60,ilout=40
  character(len=20)   :: name, ch_err

  if(psb_get_errstatus().ne.0) return 
  info=0
  err=0
  call psb_erractionsave(err_act)
  name = 'psb_dprecbld'

  if (debug) write(0,*) 'Entering precbld',P%prec,desc_a%matrix_data(:)
  info = 0
  int_err(1) = 0
  ictxt = psb_cd_get_context(desc_a)

  if (debug) write(0,*) 'Preconditioner psb_info'
  call psb_info(ictxt, me, np)

  if (present(upd)) then 
    if (debug) write(0,*) 'UPD ', upd
    if ((upd.eq.'F').or.(upd.eq.'T')) then
      iupd=upd
    else
      iupd='F'
    endif
  else
    iupd='F'
  endif

  if (.not.allocated(p%baseprecv)) then 
    !! Error 1: should call precset
    info=4010
    ch_err='unallocated bpv'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999
  end if
  !
  ! Should add check to ensure all procs have the same... 
  !
  ! ALso should define symbolic names for the preconditioners. 
  !
  if (size(p%baseprecv) >= 1) then 
    call init_baseprc_av(p%baseprecv(1),info)
    if (info /= 0) then 
      info=4010
      ch_err='allocate'
      call psb_errpush(info,name,a_err=ch_err)
      goto 9999
    endif

    call mld_baseprc_bld(a,desc_a,p%baseprecv(1),info,iupd)

  else
    info=4010
    ch_err='size bpv'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999

  endif

  if (size(p%baseprecv) > 1) then

    do i=2, size(p%baseprecv)
      
      call init_baseprc_av(p%baseprecv(i),info)
      if (info /= 0) then 
        info=4010
        ch_err='allocate'
        call psb_errpush(info,name,a_err=ch_err)
        goto 9999
      endif

      call mld_mlprec_bld(p%baseprecv(i-1)%base_a,p%baseprecv(i-1)%base_desc,&
           & p%baseprecv(i),info)
      if (dump_aggr) then 
        call psb_csprt(90+me,p%baseprecv(i)%base_a,head='%  Smoothed aggregate.')
      end if

      if (info /= 0) then 
        info=4010
        call psb_errpush(info,name)
        goto 9999
      endif

      if (debug) then 
        write(0,*) 'Return from ',i-1,' call to mlprcbld ',info
      endif
      
    end do

  endif

  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

contains

  subroutine init_baseprc_av(p,info)
    type(psb_dbaseprc_type), intent(inout) :: p
    integer                                :: info
    if (allocated(p%av)) then 
      ! Have not decided what to do yet
    end if
    allocate(p%av(max_avsz),stat=info)
!!$    if (info /= 0) return
    do k=1,size(p%av)
      call psb_nullify_sp(p%av(k))
    end do
    
  end subroutine init_baseprc_av

end subroutine psb_dprecbld