!!$ 
!!$ 
!!$                           MLD2P4  version 2.0
!!$  MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$             based on PSBLAS (Parallel Sparse BLAS version 3.0)
!!$  
!!$  (C) Copyright 2008,2009,2010
!!$
!!$                      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_dmlprec_bld.f90
!
! Subroutine: mld_dmlprec_bld
! Version:    real
!
!  This routine builds the preconditioner according to the requirements made by
!  the user trough the subroutines mld_precinit and mld_precset.
!  
!  A multilevel preconditioner is regarded as an array of 'one-level' data structures,
!  each containing the part of the preconditioner associated to a certain level,
!  (for more details see the description of mld_Tonelev_type in mld_prec_type.f90).
!  The levels are numbered in increasing order starting from the finest one, i.e.
!  level 1 is the finest level. No transfer operators are associated to level 1.
! 
!
! Arguments:
!    a       -  type(psb_dspmat_type).
!               The sparse matrix structure containing the local part of the
!               matrix to be preconditioned.
!    desc_a  -  type(psb_desc_type), input.
!               The communication descriptor of a.
!    p       -  type(mld_dprec_type), input/output.
!               The preconditioner data structure containing the local part
!               of the preconditioner to be built.
!    info    -  integer, output.
!               Error code.              
!  
subroutine mld_dmlprec_bld(a,desc_a,p,info)

  use psb_base_mod
  use mld_d_inner_mod, mld_protect_name => mld_dmlprec_bld
  use mld_d_prec_mod

  Implicit None

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

  ! Local Variables
  type(mld_dprec_type)    :: t_prec
  Integer      :: err,i,k,ictxt, me,np, err_act, iszv, newsz
  integer      :: ipv(mld_ifpsz_), val
  integer      :: int_err(5)
  character    :: upd_
  type(mld_dml_parms) :: prm
  integer            :: debug_level, debug_unit
  character(len=20)  :: name, ch_err

  if (psb_get_errstatus().ne.0) return 
  info=psb_success_
  err=0
  call psb_erractionsave(err_act)
  debug_unit  = psb_get_debug_unit()
  debug_level = psb_get_debug_level()

  name = 'mld_dmlprec_bld'
  info = psb_success_
  int_err(1) = 0
  ictxt = psb_cd_get_context(desc_a)
  call psb_info(ictxt, me, np)

  if (debug_level >= psb_debug_outer_) &
       & write(debug_unit,*) me,' ',trim(name),&
       & 'Entering '
  !
  ! For the time being we are commenting out the UPDATE argument
  ! we plan to resurrect it later. 
!!$  if (present(upd)) then 
!!$    if (debug_level >= psb_debug_outer_) &
!!$         & write(debug_unit,*) me,' ',trim(name),'UPD ', upd
!!$
!!$    if ((psb_toupper(upd).eq.'F').or.(psb_toupper(upd).eq.'T')) then
!!$      upd_=psb_toupper(upd)
!!$    else
!!$      upd_='F'
!!$    endif
!!$  else
!!$    upd_='F'
!!$  endif
  upd_ = 'F'

  if (.not.allocated(p%precv)) then 
    !! Error: should have called mld_dprecinit
    info=3111
    call psb_errpush(info,name)
    goto 9999
  end if

  !
  ! Check to ensure all procs have the same 
  !   
  newsz = -1
  iszv  = size(p%precv)
  call psb_bcast(ictxt,iszv)
  if (iszv /= size(p%precv)) then 
    info=psb_err_internal_error_
    call psb_errpush(info,name,a_err='Inconsistent size of precv')
    goto 9999
  end if

  if (iszv <= 1) then
    ! We should only ever get here for multilevel.
    info=psb_err_from_subroutine_
    ch_err='size bpv'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999
  endif


    if (iszv > 1) then

      !
      ! Build the matrix and the transfer operators corresponding
      ! to the remaining levels
      !
      !
      ! Check on the iprcparm contents: they should be the same
      ! on all processes.
      !
      call psb_bcast(ictxt,p%precv(1)%parms)
      !
      ! Finest level first; remember to fix base_a and base_desc
      ! 
      p%precv(1)%base_a    => a
      p%precv(1)%base_desc => desc_a

      if (info /= psb_success_) then 
        call psb_errpush(psb_err_internal_error_,name,a_err='Base level precbuild.')
        goto 9999
      end if


      do i=2, iszv
        !
        ! Check on the iprcparm contents: they should be the same
        ! on all processes.
        !
        call psb_bcast(ictxt,p%precv(1)%parms)

        !
        ! Sanity checks on the parameters
        !
        if (i<iszv) then 
          !
          ! A replicated matrix only makes sense at the coarsest level
          !
          call mld_check_def(p%precv(i)%parms%coarse_mat,'Coarse matrix',&
               &   mld_distr_mat_,is_distr_ml_coarse_mat)

        else if (i == iszv) then 

!!$          call check_coarse_lev(p%precv(i)) 

        end if

        if (debug_level >= psb_debug_outer_) &
             & write(debug_unit,*) me,' ',trim(name),&
             & 'Calling mlprcbld at level  ',i
        !
        ! Build the mapping between levels i-1 and i and the matrix
        ! at level i
        ! 
        if (info == psb_success_) call mld_coarse_bld(p%precv(i-1)%base_a,&
             & p%precv(i-1)%base_desc, p%precv(i),info)

        if (info /= psb_success_) then 
          call psb_errpush(psb_err_internal_error_,name,&
               & a_err='Init upper level preconditioner')
          goto 9999
        endif

        if (debug_level >= psb_debug_outer_) &
             & write(debug_unit,*) me,' ',trim(name),&
             & 'Return from ',i,' call to mlprcbld ',info      

        if (i>2) then 
          if (all(p%precv(i)%map%naggr == p%precv(i-1)%map%naggr)) then 
            newsz=i-1
          end if
          call psb_bcast(ictxt,newsz)
          if (newsz > 0) exit
        end if
      end do

      if (newsz > 0) then 
        if (me == 0) then 
          write(debug_unit,*) trim(name),&
               &': Warning: aggregates from level ',&
               & newsz
          write(debug_unit,*) trim(name),&
               &':                       to level ',&
               & iszv,' coincide.'
          write(debug_unit,*) trim(name),&
               &': Number of levels actually used :',newsz
          write(debug_unit,*)
        end if
        allocate(t_prec%precv(newsz),stat=info)
        if (info /= psb_success_) then 
          call psb_errpush(psb_err_from_subroutine_,name,&
               & a_err='prec reallocation')
          goto 9999
        endif
        do i=1,newsz-1
          call mld_move_alloc(p%precv(i),t_prec%precv(i),info)
        end do
        call mld_move_alloc(p%precv(iszv),t_prec%precv(newsz),info)
        do i=newsz+1, iszv
          call mld_precfree(p%precv(i),info)
        end do
        call mld_move_alloc(t_prec,p,info) 
        ! Ignore errors from transfer
        info = psb_success_
        !
        ! Restart
        iszv = newsz
        ! Fix the pointers, but the level 1 should
        ! be already OK
        do i=2, iszv - 1 
          p%precv(i)%base_a    => p%precv(i)%ac
          p%precv(i)%base_desc => p%precv(i)%desc_ac
          p%precv(i)%map%p_desc_X => p%precv(i-1)%base_desc
          p%precv(i)%map%p_desc_Y => p%precv(i)%base_desc
        end do


        i    = iszv 
        call check_coarse_lev(p%precv(i)) 
        if (info == psb_success_) call mld_coarse_bld(p%precv(i-1)%base_a,&
             & p%precv(i-1)%base_desc, p%precv(i),info)
        if (info /= psb_success_) then 
          call psb_errpush(psb_err_from_subroutine_,name,a_err='coarse rebuild')
          goto 9999
        endif
      end if
    end if

    do i=1, iszv
      !
      ! build the base preconditioner at level i
      !
      if (debug_level >= psb_debug_outer_) &
           & write(debug_unit,*) me,' ',trim(name),&
           & 'Calling mlprcbld at level  ',i
      call mld_check_def(p%precv(i)%parms%sweeps,&
           & 'Jacobi sweeps',1,is_legal_jac_sweeps)
      call mld_check_def(p%precv(i)%parms%sweeps_pre,&
           & 'Jacobi sweeps',1,is_legal_jac_sweeps)
      call mld_check_def(p%precv(i)%parms%sweeps_post,&
           & 'Jacobi sweeps',1,is_legal_jac_sweeps)

      if (.not.allocated(p%precv(i)%sm)) then 
        !! Error: should have called mld_dprecinit
        info=3111
        call psb_errpush(info,name)
        goto 9999
      end if
      if (.not.allocated(p%precv(i)%sm%sv)) then 
        !! Error: should have called mld_dprecinit
        info=3111
        call psb_errpush(info,name)
        goto 9999
      end if


      !
      !  Test version for beginning of OO stuff. 
      ! 
      call p%precv(i)%sm%build(p%precv(i)%base_a,p%precv(i)%base_desc,'F',info)

      if (info /= psb_success_) then 
        call psb_errpush(psb_err_internal_error_,name,&
             & a_err='One level preconditioner build.')
        goto 9999
      endif

      if (debug_level >= psb_debug_outer_) &
           & write(debug_unit,*) me,' ',trim(name),&
           & 'Return from ',i,' call to mlprcbld ',info      
    end do


  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 check_coarse_lev(prec)
    type(mld_donelev_type) :: prec

    !
    ! At the coarsest level, check mld_coarse_solve_ 
    !
!!$    val = prec%parms%coarse_solve
!!$    select case (val) 
!!$    case(mld_jac_)   
!!$
!!$      if (prec%prec%iprcparm(mld_sub_solve_) /= mld_diag_scale_) then 
!!$        if (me == 0) write(debug_unit,*)&
!!$             & 'Warning: inconsistent coarse level specification.'
!!$        if (me == 0) write(debug_unit,*)&
!!$             & '         Resetting according to the value specified for mld_coarse_solve_.'
!!$        prec%prec%iprcparm(mld_sub_solve_)    = mld_diag_scale_
!!$      end if
!!$      prec%prec%iprcparm(mld_smoother_type_)  = mld_jac_          
!!$
!!$    case(mld_bjac_)   
!!$
!!$      if ((prec%prec%iprcparm(mld_sub_solve_) == mld_diag_scale_).or.&
!!$           & ( prec%prec%iprcparm(mld_smoother_type_) /= mld_bjac_))  then 
!!$        if (me == 0) write(debug_unit,*)&
!!$             & 'Warning: inconsistent coarse level specification.'
!!$        if (me == 0) write(debug_unit,*)&
!!$             & '         Resetting according to the value specified for mld_coarse_solve_.'
!!$! !$#if defined(HAVE_UMF_)
!!$! !$        prec%prec%iprcparm(mld_sub_solve_)       = mld_umf_
!!$! !$#elif defined(HAVE_SLU_)
!!$! !$        prec%prec%iprcparm(mld_sub_solve_)       = mld_slu_
!!$! !$#else 
!!$        prec%prec%iprcparm(mld_sub_solve_)       = mld_ilu_n_
!!$! !$#endif
!!$      end if
!!$      prec%prec%iprcparm(mld_smoother_type_)  = mld_bjac_          
!!$
!!$    case(mld_umf_, mld_slu_)
!!$      if ((prec%iprcparm(mld_coarse_mat_)  /= mld_repl_mat_).or.&
!!$           & (prec%prec%iprcparm(mld_sub_solve_)  /= val)) then 
!!$        if (me == 0) write(debug_unit,*)&
!!$             & 'Warning: inconsistent coarse level specification.'
!!$        if (me == 0) write(debug_unit,*)&
!!$             & '         Resetting according to the value specified for mld_coarse_solve_.'
!!$        prec%iprcparm(mld_coarse_mat_)         = mld_repl_mat_
!!$        prec%prec%iprcparm(mld_sub_solve_)     = val
!!$        prec%prec%iprcparm(mld_smoother_type_) = mld_bjac_          
!!$      end if
!!$    case(mld_sludist_)
!!$      if ((prec%iprcparm(mld_coarse_mat_)  /= mld_distr_mat_).or.&
!!$           & (prec%prec%iprcparm(mld_sub_solve_)  /= val)) then 
!!$        if (me == 0) write(debug_unit,*)&
!!$             & 'Warning: inconsistent coarse level specification.'
!!$        if (me == 0) write(debug_unit,*)&
!!$             & '         Resetting according to the value specified for mld_coarse_solve_.'
!!$        prec%iprcparm(mld_coarse_mat_)           = mld_distr_mat_
!!$        prec%prec%iprcparm(mld_sub_solve_)       = val
!!$        prec%prec%iprcparm(mld_smoother_type_)   = mld_bjac_          
!!$        prec%prec%iprcparm(mld_smoother_sweeps_) = 1
!!$      end if
!!$    end select
  end subroutine check_coarse_lev

end subroutine mld_dmlprec_bld