amg4psblas/mlprec/impl/mld_s_smoothers_bld.f90

!   
!   
!                             MLD2P4  version 2.1
!    MultiLevel Domain Decomposition Parallel Preconditioners Package
!               based on PSBLAS (Parallel Sparse BLAS version 3.4)
!    
!    (C) Copyright 2008, 2010, 2012, 2015, 2017 
!  
!        Salvatore Filippone    Cranfield University
!        Ambra Abdullahi Hassan University of Rome Tor Vergata
!        Alfredo Buttari        CNRS-IRIT, Toulouse
!        Pasqua D'Ambra         ICAR-CNR, Naples
!        Daniela di Serafino    University of Campania "L. Vanvitelli", Caserta
!   
!    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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!         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
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!    POSSIBILITY OF SUCH DAMAGE.
!   
!  
! File: mld_s_smoothers_bld.f90
!
! Subroutine: mld_s_smoothers_bld
! Version:    real
!
!  This routine performs the final phase of the multilevel preconditioner build process:
!  builds the "smoother" objects at each level, based on the matrix hierarchy prepared
!  by mld_s_hierarchy_bld.
!  
!  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.
!  Each level provides a "build" method; for the base type, the "one-level"
!  build procedure simply invokes the build method of the first smoother object,
!  and also on the second object if allocated. 
! 
!
! Arguments:
!    a       -  type(psb_sspmat_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_sprec_type), input/output.
!               The preconditioner data structure containing the local part
!               of the preconditioner to be built.
!    info    -  integer, output.
!               Error code.              
!
!    amold   -  class(psb_s_base_sparse_mat), input, optional
!               Mold for the inner format of matrices contained in the
!               preconditioner
!
!
!    vmold   -  class(psb_s_base_vect_type), input, optional
!               Mold for the inner format of vectors contained in the
!               preconditioner
!
!
!  
subroutine mld_s_smoothers_bld(a,desc_a,prec,info,amold,vmold,imold)

  use psb_base_mod
  !use mld_s_inner_mod
  use mld_s_prec_mod, mld_protect_name => mld_s_smoothers_bld

  Implicit None

  ! Arguments
  type(psb_sspmat_type),intent(in), target           :: a
  type(psb_desc_type), intent(inout), target           :: desc_a
  class(mld_sprec_type),intent(inout),target         :: prec
  integer(psb_ipk_), intent(out)                       :: info
  class(psb_s_base_sparse_mat), intent(in), optional :: amold
  class(psb_s_base_vect_type), intent(in), optional  :: vmold
  class(psb_i_base_vect_type), intent(in), optional  :: imold
!!$  character, intent(in), optional         :: upd

  ! Local Variables
  integer(psb_ipk_)  :: ictxt, me,np
  integer(psb_ipk_)  :: err,i,k, err_act, iszv, newsz, casize, nplevs, mxplevs
  real(psb_spk_)     :: mnaggratio
  integer(psb_ipk_)  :: ipv(mld_ifpsz_), val
  integer(psb_ipk_)  :: int_err(5)
  character          :: upd_
  integer(psb_ipk_)  :: 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_s_smoothers_bld'
  info = psb_success_
  int_err(1) = 0
  ictxt = desc_a%get_context()
  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(prec%precv)) then 
    !! Error: should have called mld_sprecinit
    info=3111
    call psb_errpush(info,name)
    goto 9999
  end if

  !
  ! Check to ensure all procs have the same 
  !   
  iszv       = size(prec%precv)
  call psb_bcast(ictxt,iszv)
  if (iszv /= size(prec%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 never get here.
    info=psb_err_from_subroutine_
    ch_err='size bpv'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999
  endif
    
  !
  ! Now do the real build.
  !

  do i=1, iszv
    !
    ! build the base preconditioner at level i
    !
    call prec%precv(i)%bld(info,amold=amold,vmold=vmold,imold=imold)
    
    if (info /= psb_success_) then 
      write(ch_err,'(a,i7)') 'Error @ level',i
      call psb_errpush(psb_err_internal_error_,name,&
           & a_err=ch_err)
      goto 9999
    endif

  end do

  if (debug_level >= psb_debug_outer_) &
       & write(debug_unit,*) me,' ',trim(name),&
       & 'Exiting with',iszv,' levels'

  call psb_erractionrestore(err_act)
  return

9999 call psb_error_handler(err_act)

  return

end subroutine mld_s_smoothers_bld