!!$ 
!!$              Parallel Sparse BLAS  version 3.4
!!$    (C) Copyright 2006, 2010, 2015
!!$                       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
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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 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.
!!$ 
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!!$  
module psb_s_mat_dist_mod
  use psb_base_mod, only :  psb_ipk_, psb_spk_, psb_desc_type, psb_parts, &
       & psb_sspmat_type, psb_s_base_sparse_mat, psb_s_vect_type

  interface psb_matdist
    subroutine psb_smatdist(a_glob, a, ictxt, desc_a,&
         & info, b_glob, b, x_glob, x, parts, v, inroot,fmt,mold)
      !
      ! an utility subroutine to distribute a matrix among processors
      ! according to a user defined data distribution, using
      ! sparse matrix subroutines.
      !
      !  type(psb_sspmat)                       :: a_glob
      !     on entry: this contains the global sparse matrix as follows:
      !
      !  type(psb_sspmat_type)                            :: a
      !     on exit : this will contain the local sparse matrix.
      !
      !       interface parts
      !         !   .....user passed subroutine.....
      !         subroutine parts(global_indx,n,np,pv,nv)
      !           implicit none
      !           integer(psb_ipk_), intent(in)  :: global_indx, n, np
      !           integer(psb_ipk_), intent(out) :: nv
      !           integer(psb_ipk_), intent(out) :: pv(*)
      !
      !       end subroutine parts
      !       end interface
      !     on entry:  subroutine providing user defined data distribution.
      !        for each global_indx the subroutine should return
      !        the list  pv of all processes owning the row with
      !        that index; the list will contain nv entries.
      !        usually nv=1; if nv >1 then we have an overlap in the data
      !        distribution.
      !
      !  integer(psb_ipk_) :: ictxt
      !     on entry: the PSBLAS parallel environment context.
      !
      !  type (desc_type)                  :: desc_a
      !     on exit : the updated array descriptor
      !
      !  real(psb_spk_),  optional      :: b_glob(:)
      !     on entry: RHS      
      !     
      !  type(psb_s_vect_type), optional      :: b
      !     on exit : this will contain the local right hand side.
      !
      !  real(psb_spk_),  optional      :: x_glob(:)
      !     on entry: initial guess      
      !     
      !  type(psb_s_vect_type), optional      :: x
      !     on exit : this will contain the local right hand side.
      !
      !  integer(psb_ipk_), optional    :: inroot
      !     on entry: specifies processor holding a_glob. default: 0
      !     on exit : unchanged.
      !
      import :: psb_ipk_, psb_sspmat_type, psb_spk_, psb_desc_type,&
           & psb_s_base_sparse_mat, psb_s_vect_type, psb_parts
      implicit none

      ! parameters
      type(psb_sspmat_type)      :: a_glob
      integer(psb_ipk_) :: ictxt
      type(psb_sspmat_type)      :: a
      type(psb_desc_type)        :: desc_a
      integer(psb_ipk_), intent(out)       :: info
      real(psb_spk_), optional       :: b_glob(:)
      type(psb_s_vect_type), optional   :: b
      real(psb_spk_), optional       :: x_glob(:)
      type(psb_s_vect_type), optional   :: x
      integer(psb_ipk_), optional       :: inroot
      character(len=*), optional :: fmt
      class(psb_s_base_sparse_mat), optional :: mold
      procedure(psb_parts), optional  :: parts
      integer(psb_ipk_), optional     :: v(:)
    end subroutine psb_smatdist
  end interface

end module psb_s_mat_dist_mod