!!$ 
!!$              Parallel Sparse BLAS  version 3.1
!!$    (C) Copyright 2006, 2007, 2008, 2009, 2010, 2012, 2013
!!$                       Salvatore Filippone    University of Rome Tor Vergata
!!$                       Alfredo Buttari        CNRS-IRIT, Toulouse
!!$ 
!!$  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 PSBLAS 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 PSBLAS GROUP OR ITS CONTRIBUTORS
!!$  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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!!$  POSSIBILITY OF SUCH DAMAGE.
!!$ 
!!$  

subroutine psb_s_diag_dump(prec,info,prefix,head)
  use psb_base_mod
  use psb_s_diagprec, psb_protect_name => psb_s_diag_dump
  implicit none 
  class(psb_s_diag_prec_type), intent(in) :: prec
  integer(psb_ipk_), intent(out)                    :: info
  character(len=*), intent(in), optional  :: prefix,head
  integer(psb_ipk_) :: i, j, il1, iln, lname, lev
  integer(psb_ipk_) :: ictxt,iam, np
  character(len=80)  :: prefix_
  character(len=120) :: fname ! len should be at least 20 more than

  !  len of prefix_ 

  info = 0
  ictxt = prec%get_ctxt()
  call psb_info(ictxt,iam,np)

  if (present(prefix)) then 
    prefix_ = trim(prefix(1:min(len(prefix),len(prefix_))))
  else
    prefix_ = "dump_diag_s"
  end if

  lname = len_trim(prefix_)
  fname = trim(prefix_)
  write(fname(lname+1:lname+5),'(a,i3.3)') '_p',iam
  write(fname(lname+1:),'(a,a)')'_diag.mtx'
  if (allocated(prec%dv)) &
       & call psb_geprt(fname,prec%dv%v%v,head=head)

end subroutine psb_s_diag_dump


subroutine psb_s_diag_apply_vect(alpha,prec,x,beta,y,desc_data,info,trans,work)
  use psb_base_mod
  use psb_s_diagprec, psb_protect_name =>  psb_s_diag_apply_vect
  implicit none 
  type(psb_desc_type),intent(in)    :: desc_data
  class(psb_s_diag_prec_type), intent(inout)  :: prec
  type(psb_s_vect_type),intent(inout)   :: x
  real(psb_spk_),intent(in)         :: alpha, beta
  type(psb_s_vect_type),intent(inout)   :: y
  integer(psb_ipk_), intent(out)              :: info
  character(len=1), optional        :: trans
  real(psb_spk_),intent(inout), optional, target :: work(:)
  integer(psb_ipk_) :: err_act, nrow, ierr(5)
  character(len=20)  :: name='s_diag_prec_apply'
  real(psb_spk_), pointer :: ww(:)
  class(psb_s_base_vect_type), allocatable :: dw

  call psb_erractionsave(err_act)

  !
  ! This is the base version and we should throw an error. 
  ! Or should it be the DIAG preonditioner???
  !
  info = psb_success_

  nrow = desc_data%get_local_rows()
  if (x%get_nrows() < nrow) then 
    info = 36; ierr(1) = 2; ierr(2) = nrow;
    call psb_errpush(info,name,i_err=ierr)
    goto 9999
  end if
  if (y%get_nrows() < nrow) then 
    info = 36; ierr(1) = 3; ierr(2) = nrow;
    call psb_errpush(info,name,i_err=ierr)
    goto 9999
  end if
  if (.not.allocated(prec%d)) then
    info = 1124
    call psb_errpush(info,name,a_err="preconditioner: D")
    goto 9999
  end if
  if (size(prec%d) < nrow) then
    info = 1124
    call psb_errpush(info,name,a_err="preconditioner: D")
    goto 9999
  end if

  if (size(work) >= x%get_nrows()) then 
    ww => work
  else
    allocate(ww(x%get_nrows()),stat=info)
    if (info /= psb_success_) then 
      ierr(1) = x%get_nrows()
      call psb_errpush(psb_err_alloc_request_,name,&
           & i_err=ierr,a_err='real(psb_spk_)')
      goto 9999      
    end if
  end if


  call y%mlt(alpha,prec%dv,x,beta,info,conjgx=trans)

  if (size(work) < x%get_nrows()) then 
    deallocate(ww,stat=info)
    if (info /= psb_success_) then 
      call psb_errpush(psb_err_from_subroutine_, &
           & name,a_err='Deallocate')
      goto 9999      
    end if
  end if

  call psb_erractionrestore(err_act)
  return

9999 continue
  call psb_erractionrestore(err_act)
  if (err_act == psb_act_abort_) then
    call psb_error()
    return
  end if
  return

end subroutine psb_s_diag_apply_vect


subroutine psb_s_diag_apply(alpha,prec,x,beta,y,desc_data,info,trans,work)
  use psb_base_mod
  use psb_s_diagprec, psb_protect_name =>  psb_s_diag_apply
  implicit none 

  type(psb_desc_type),intent(in)    :: desc_data
  class(psb_s_diag_prec_type), intent(in)  :: prec
  real(psb_spk_),intent(inout)      :: x(:)
  real(psb_spk_),intent(in)         :: alpha, beta
  real(psb_spk_),intent(inout)      :: y(:)
  integer(psb_ipk_), intent(out)              :: info
  character(len=1), optional        :: trans
  real(psb_spk_),intent(inout), optional, target :: work(:)
  integer(psb_ipk_) :: err_act, nrow, ierr(5)
  character :: trans_
  character(len=20)  :: name='s_diag_prec_apply'
  real(psb_spk_), pointer :: ww(:)

  call psb_erractionsave(err_act)

  info = psb_success_

  nrow = desc_data%get_local_rows()
  if (size(x) < nrow) then 
    info = 36; ierr(1) = 2; ierr(2) = nrow;
    call psb_errpush(info,name,i_err=ierr)
    goto 9999
  end if
  if (size(y) < nrow) then 
    info = 36; ierr(1) = 3; ierr(2) = nrow;
    call psb_errpush(info,name,i_err=ierr)
    goto 9999
  end if
  if (.not.allocated(prec%d)) then
    info = 1124
    call psb_errpush(info,name,a_err="preconditioner: D")
    goto 9999
  end if
  if (size(prec%d) < nrow) then
    info = 1124
    call psb_errpush(info,name,a_err="preconditioner: D")
    goto 9999
  end if
  if (present(trans)) then 
    trans_ = psb_toupper(trans)
  else
    trans_='N'
  end if

  select case(trans_)
  case('N')
  case('T','C')
  case default
    info=psb_err_iarg_invalid_i_
    ierr(1) = 6
    call psb_errpush(info,name,i_err=ierr,a_err=trans_)
    goto 9999
  end select

  if (size(work) >= size(x)) then 
    ww => work
  else
    allocate(ww(size(x)),stat=info)
    if (info /= psb_success_) then 
      ierr(1) = size(x)
      call psb_errpush(psb_err_alloc_request_,name,&
           & i_err=ierr,a_err='real(psb_spk_)')
      goto 9999      
    end if
  end if


  if (trans_ == 'C') then 
    ww(1:nrow) = x(1:nrow)*(prec%d(1:nrow))
  else
    ww(1:nrow) = x(1:nrow)*prec%d(1:nrow)
  endif
  call psb_geaxpby(alpha,ww,beta,y,desc_data,info)

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

  call psb_erractionrestore(err_act)
  return

9999 continue
  call psb_erractionrestore(err_act)
  if (err_act == psb_act_abort_) then
    call psb_error()
    return
  end if
  return

end subroutine psb_s_diag_apply


subroutine psb_s_diag_precbld(a,desc_a,prec,info,upd,amold,afmt,vmold)
  use psb_base_mod
  use psb_s_diagprec, psb_protect_name =>  psb_s_diag_precbld

  Implicit None

  type(psb_sspmat_type), intent(in), target :: a
  type(psb_desc_type), intent(in), target   :: desc_a
  class(psb_s_diag_prec_type),intent(inout) :: prec
  integer(psb_ipk_), intent(out)                      :: info
  character, intent(in), optional           :: upd
  character(len=*), intent(in), optional    :: afmt
  class(psb_s_base_sparse_mat), intent(in), optional :: amold
  class(psb_s_base_vect_type), intent(in), optional  :: vmold
  integer(psb_ipk_) :: err_act, nrow,i
  character(len=20)  :: name='s_diag_precbld'

  call psb_erractionsave(err_act)

  info = psb_success_
  nrow = desc_a%get_local_cols()
  if (allocated(prec%d)) then 
    if (size(prec%d) < nrow) then 
      deallocate(prec%d,stat=info)
    end if
  end if
  if ((info == psb_success_).and.(.not.allocated(prec%d))) then 
    allocate(prec%d(nrow), stat=info)
  end if
  if (info /= psb_success_) then 
    info = psb_err_alloc_dealloc_
    call psb_errpush(info,name)
    goto 9999
  end if

  call a%get_diag(prec%d,info) 
  if (info /= psb_success_) then 
    info = psb_err_from_subroutine_
    call psb_errpush(info,name, a_err='get_diag')
    goto 9999
  end if

  do i=1,nrow
    if (prec%d(i) == dzero) then
      prec%d(i) = done
    else
      prec%d(i) = done/prec%d(i)
    endif
  end do
  allocate(prec%dv,stat=info) 
  if (info == 0) then 
    if (present(vmold)) then 
      allocate(prec%dv%v,mold=vmold,stat=info) 
    else
      allocate(psb_s_base_vect_type :: prec%dv%v,stat=info) 
    end if
  end if
  if (info == 0) then 
    call prec%dv%bld(prec%d)
  else 
    write(0,*) 'Error on precbld ',info
  end if

  call psb_erractionrestore(err_act)
  return

9999 continue
  call psb_erractionrestore(err_act)
  if (err_act == psb_act_abort_) then
    call psb_error()
    return
  end if
  return
end subroutine psb_s_diag_precbld