!  
!   
!                             MLD2P4  version 2.1
!    MultiLevel Domain Decomposition Parallel Preconditioners Package
!               based on PSBLAS (Parallel Sparse BLAS version 3.5)
!    
!    (C) Copyright 2008, 2010, 2012, 2015, 2017 
!  
!        Salvatore Filippone    Cranfield University, UK
!        Pasqua D'Ambra         IAC-CNR, Naples, IT
!        Daniela di Serafino    University of Campania "L. Vanvitelli", Caserta, IT
!   
!    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.
!   
!  
subroutine mld_s_base_smoother_apply_vect(alpha,sm,x,beta,y,desc_data,&
     &  trans,sweeps,work,info,init,initu,wv)
  use psb_base_mod
  use mld_s_base_smoother_mod, mld_protect_name =>  mld_s_base_smoother_apply_vect
  implicit none 
  type(psb_desc_type), intent(in)                 :: desc_data
  class(mld_s_base_smoother_type), intent(inout) :: sm
  type(psb_s_vect_type),intent(inout)            :: x
  type(psb_s_vect_type),intent(inout)            :: y
  real(psb_spk_),intent(in)                       :: alpha,beta
  character(len=1),intent(in)                      :: trans
  integer(psb_ipk_), intent(in)                    :: sweeps
  real(psb_spk_),target, intent(inout)            :: work(:)
  integer(psb_ipk_), intent(out)                   :: info
  character, intent(in), optional                  :: init
  type(psb_s_vect_type),intent(inout), optional   :: initu
  type(psb_s_vect_type),intent(inout), optional   :: wv(:)
  !    
  integer(psb_ipk_) :: err_act
  character(len=20) :: name='s_base_smoother_apply'

  call psb_erractionsave(err_act)
  info = psb_success_
  if (sweeps == 0) then
    
    !
    ! K^0 = I
    ! zero sweeps  of any smoother is just the identity.
    !
    call psb_geaxpby(alpha,x,beta,y,desc_data,info) 

  else
    if (allocated(sm%sv)) then
      call sm%sv%apply(alpha,x,beta,y,desc_data,trans,work,info,init=init, initu=initu)
    else
      info = 1121
    endif
  end if
  if (info /= psb_success_) then 
    call psb_errpush(info,name)
    goto 9999 
  end if

  call psb_erractionrestore(err_act)
  return

9999 call psb_error_handler(err_act)

  return

end subroutine mld_s_base_smoother_apply_vect