amg4psblas/mlprec/mld_cprecaply.f90

!!$
!!$ 
!!$                           MLD2P4  version 1.1
!!$  MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$             based on PSBLAS (Parallel Sparse BLAS version 2.3.1)
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!!$                      Salvatore Filippone  University of Rome Tor Vergata
!!$                      Alfredo Buttari      University of Rome Tor Vergata
!!$                      Pasqua D'Ambra       ICAR-CNR, Naples
!!$                      Daniela di Serafino  Second University of Naples
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! File: mld_cprecaply.f90
!
! Subroutine: mld_cprecaply
! Version:    complex
!
!  This routine applies the preconditioner built by mld_cprecbld, i.e. it computes
!
!                             Y = op(M^(-1)) * X,
!  where
!  - M is the preconditioner,
!  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
!  - X and Y are vectors.
!  This operation is performed at each iteration of a preconditioned Krylov solver.
!
!
! Arguments:
!    prec       -  type(mld_cprec_type), input.
!                  The preconditioner data structure containing the local part
!                  of the preconditioner to be applied.
!    x          -  complex(psb_spk_), dimension(:), input.
!                  The local part of the vector X in Y = op(M^(-1)) * X.
!    y          -  complex(psb_spk_), dimension(:), output.
!                  The local part of the vector Y in Y = op(M^(-1)) * X.
!    desc_data  -  type(psb_desc_type), input.
!                  The communication descriptor associated to the matrix to be
!                  preconditioned.
!    info       -  integer, output.
!                  Error code.
!    trans      -  character(len=1), optional.
!                  If trans='N','n' then op(M^(-1)) = M^(-1);
!                  if trans='T','t' then op(M^(-1)) = M^(-T) (transpose of M^(-1)).
!    work       -  complex(psb_spk_), dimension (:), optional, target.
!                  Workspace. Its size must be at
!                  least 4*psb_cd_get_local_cols(desc_data).
!    
subroutine mld_cprecaply(prec,x,y,desc_data,info,trans,work)

  use psb_base_mod
  use mld_inner_mod
  use mld_prec_mod, mld_protect_name => mld_cprecaply

  implicit none
  
  ! Arguments
  type(psb_desc_type),intent(in)      :: desc_data
  type(mld_cprec_type), intent(in)    :: prec
  complex(psb_spk_),intent(in)      :: x(:)
  complex(psb_spk_),intent(inout)   :: y(:)
  integer, intent(out)                :: info
  character(len=1), optional          :: trans
  complex(psb_spk_), optional, target  :: work(:)

  ! Local variables
  character     :: trans_ 
  complex(psb_spk_), pointer :: work_(:)
  integer :: ictxt,np,me,err_act,iwsz
  character(len=20)   :: name
  
  name='mld_cprecaply'
  info = 0
  call psb_erractionsave(err_act)

  ictxt = psb_cd_get_context(desc_data)
  call psb_info(ictxt, me, np)

  if (present(trans)) then 
    trans_=psb_toupper(trans)
  else
    trans_='N'
  end if

  if (present(work)) then 
    work_ => work
  else
    iwsz = max(1,4*psb_cd_get_local_cols(desc_data))
    allocate(work_(iwsz),stat=info)
    if (info /= 0) then 
      call psb_errpush(4025,name,i_err=(/iwsz,0,0,0,0/),&
           & a_err='complex(psb_spk_)')
      goto 9999      
    end if

  end if

  if (.not.(allocated(prec%precv))) then 
    !! Error 1: should call mld_dprecbld
    info=3112
    call psb_errpush(info,name)
    goto 9999
  end if
  if (size(prec%precv) >1) then
    !
    ! Number of levels > 1: apply the multilevel preconditioner
    ! 
    call mld_mlprec_aply(cone,prec,x,czero,y,desc_data,trans_,work_,info)
    if(info /= 0) then
      call psb_errpush(4010,name,a_err='mld_cmlprec_aply')
      goto 9999
    end if

  else  if (size(prec%precv) == 1) then 
    !
    ! Number of levels = 1: apply the base preconditioner
    !
    call mld_baseprec_aply(cone,prec%precv(1)%prec,x,czero,y,desc_data,trans_, work_,info)
  else 
    info = 4013
    call psb_errpush(info,name,a_err='Invalid size of precv',&
         & i_Err=(/size(prec%precv),0,0,0,0/))
    goto 9999
  endif

  ! If the original distribution has an overlap we should fix that. 
  call psb_halo(y,desc_data,info,data=psb_comm_mov_)


  if (present(work)) then 
  else
    deallocate(work_)
  end if

  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

end subroutine mld_cprecaply


! File: mld_cprecaply.f90.
!
! Subroutine: mld_cprecaply1.
! Version:    complex.
!
!  Applies the preconditioner built by mld_cprecbld, i.e. computes
!
!                             X = op(M^(-1)) * X,
!  where
!  - M is the preconditioner,
!  - op(M^(-1)) is M^(-1) or its transpose, according to the value of trans,
!  - X is a vectors.
!  This operation is performed at each iteration of a preconditioned Krylov solver.
!
!  This routine differs from mld_cprecaply because the preconditioned vector X
!  overwrites the original one.
!
!
! Arguments:
!    prec       -  type(mld_cprec_type), input.
!                  The preconditioner data structure containing the local part
!                  of the preconditioner to be applied.
!    x          -  complex(psb_spk_), dimension(:), input/output.
!                  The local part of vector X in X := op(M^(-1)) * X.
!    desc_data  -  type(psb_desc_type), input.
!                  The communication descriptor associated to the matrix to be
!                  preconditioned.
!    info       -  integer, output.
!                  Error code.
!    trans      -  character(len=1), optional.
!                  If trans='N','n' then op(M^(-1)) = M^(-1);
!                  if trans='T','t' then op(M^(-1)) = M^(-T) (transpose of M^(-1)).
!  
subroutine mld_cprecaply1(prec,x,desc_data,info,trans)

  use psb_base_mod
  use mld_inner_mod
  use mld_prec_mod, mld_protect_name => mld_cprecaply1

  implicit none

  ! Arguments
  type(psb_desc_type),intent(in)    :: desc_data
  type(mld_cprec_type), intent(in)  :: prec
  complex(psb_spk_),intent(inout) :: x(:)
  integer, intent(out)              :: info
  character(len=1), optional        :: trans

  ! Local variables
  integer :: ictxt,np,me, err_act
  complex(psb_spk_), pointer :: WW(:), w1(:)
  character(len=20)   :: name

  name='mld_cprecaply1'
  info = 0
  call psb_erractionsave(err_act)
  

  ictxt = psb_cd_get_context(desc_data)
  call psb_info(ictxt, me, np)

  allocate(ww(size(x)),w1(size(x)),stat=info)
  if (info /= 0) then 
    info=4025
    call psb_errpush(info,name,i_err=(/2*size(x),0,0,0,0/),&
         & a_err='complex(psb_spk_)')
    goto 9999      
  end if

  call mld_precaply(prec,x,ww,desc_data,info,trans=trans,work=w1)
  if (info /= 0) then
    call psb_errpush(4010,name,a_err='mld_precaply')
    goto 9999
  end if

  x(:) = ww(:)
  deallocate(ww,W1,stat=info)
  if (info /= 0) then
    info = 4000
    call psb_errpush(info,name)
    goto 9999
  end if
  
  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
end subroutine mld_cprecaply1