!  
!   
!                             AMG4PSBLAS version 1.0
!    Algebraic Multigrid Package
!               based on PSBLAS (Parallel Sparse BLAS version 3.7)
!    
!    (C) Copyright 2021 
!  
!        Salvatore Filippone  
!        Pasqua D'Ambra   
!        Fabio Durastante        
!   
!    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 AMG4PSBLAS group or the names of its contributors may
!         not be used to endorse or promote products derived from this
!         software without specific prior 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 AMG4PSBLAS GROUP OR ITS CONTRIBUTORS
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!    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.
!   
!  
!
! File: amg_s_slu_solver_mod.f90
!
! Module: amg_s_slu_solver_mod
!
!  This module defines: 
!  - the amg_s_slu_solver_type data structure containing the ingredients
!    to interface with the SuperLU package. 
!    1. The factorization is restricted to the diagonal block of the
!       current image.
!
module amg_s_slu_solver

  use iso_c_binding
  use amg_s_base_solver_mod

#if defined(PSB_IPK8)

  type, extends(amg_s_base_solver_type) :: amg_s_slu_solver_type

  end type amg_s_slu_solver_type

#else  

  type, extends(amg_s_base_solver_type) :: amg_s_slu_solver_type
    type(c_ptr)                 :: lufactors=c_null_ptr
    integer(c_long_long)        :: symbsize=0, numsize=0
  contains
    procedure, pass(sv) :: build   => amg_s_slu_solver_bld
    procedure, pass(sv) :: apply_a => amg_s_slu_solver_apply
    procedure, pass(sv) :: apply_v => amg_s_slu_solver_apply_vect
    procedure, pass(sv) :: free    => s_slu_solver_free
    procedure, pass(sv) :: clear_data  => s_slu_solver_clear_data
    procedure, pass(sv) :: descr   => s_slu_solver_descr
    procedure, pass(sv) :: sizeof  => s_slu_solver_sizeof
    procedure, nopass   :: get_fmt => s_slu_solver_get_fmt
    procedure, nopass   :: get_id  => s_slu_solver_get_id
    final               :: s_slu_solver_finalize
  end type amg_s_slu_solver_type


  private :: s_slu_solver_free,   s_slu_solver_descr, &
       &  s_slu_solver_sizeof, &
       &  s_slu_solver_get_fmt, s_slu_solver_get_id, &
       &  s_slu_solver_clear_data
  private :: s_slu_solver_finalize



  interface 
    function amg_sslu_fact(n,nnz,values,rowptr,colind,&
         & lufactors)&
         & bind(c,name='amg_sslu_fact') result(info)
      use iso_c_binding
      integer(c_int), value :: n,nnz
      integer(c_int)        :: info
      integer(c_int)        :: rowptr(*),colind(*)
      real(c_float)        :: values(*)
      type(c_ptr)           :: lufactors
    end function amg_sslu_fact
  end interface

  interface 
    function amg_sslu_solve(itrans,n,nrhs,b,ldb,lufactors)&
         & bind(c,name='amg_sslu_solve') result(info)
      use iso_c_binding
      integer(c_int)        :: info
      integer(c_int), value :: itrans,n,nrhs,ldb
      real(c_float)        :: b(ldb,*)
      type(c_ptr), value    :: lufactors
    end function amg_sslu_solve
  end interface

  interface 
    function amg_sslu_free(lufactors)&
         & bind(c,name='amg_sslu_free') result(info)
      use iso_c_binding
      integer(c_int)        :: info
      type(c_ptr), value    :: lufactors
    end function amg_sslu_free
  end interface

  interface
    subroutine amg_s_slu_solver_bld(a,desc_a,sv,info,b,amold,vmold,imold)
      use psb_base_mod
      import amg_s_slu_solver_type
      Implicit None

      ! Arguments
      type(psb_sspmat_type), intent(inout), target        :: a
      Type(psb_desc_type), Intent(inout)                  :: desc_a 
      class(amg_s_slu_solver_type), intent(inout)         :: sv
      integer(psb_ipk_), intent(out)                      :: info
      type(psb_sspmat_type), intent(in), target, optional :: b
      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
    end subroutine amg_s_slu_solver_bld
  end interface

  interface
    subroutine amg_s_slu_solver_apply_vect(alpha,sv,x,beta,y,desc_data,&
         & trans,work,wv,info,init,initu)
      use psb_base_mod
      import amg_s_slu_solver_type
      implicit none 
      type(psb_desc_type), intent(in)      :: desc_data
      class(amg_s_slu_solver_type), intent(inout) :: sv
      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
      real(psb_spk_),target, intent(inout) :: work(:)
      type(psb_s_vect_type),intent(inout) :: wv(:)
      integer(psb_ipk_), intent(out)                 :: info
      character, intent(in), optional                :: init
      type(psb_s_vect_type),intent(inout), optional   :: initu
    end subroutine amg_s_slu_solver_apply_vect
  end interface

  interface
    subroutine amg_s_slu_solver_apply(alpha,sv,x,beta,y,desc_data,&
         & trans,work,info,init,initu)
      use psb_base_mod
      import amg_s_slu_solver_type
      implicit none 
      type(psb_desc_type), intent(in)      :: desc_data
      class(amg_s_slu_solver_type), intent(inout) :: sv
      real(psb_spk_),intent(inout)         :: x(:)
      real(psb_spk_),intent(inout)         :: y(:)
      real(psb_spk_),intent(in)            :: alpha,beta
      character(len=1),intent(in)          :: trans
      real(psb_spk_),target, intent(inout) :: work(:)
      integer(psb_ipk_), intent(out)        :: info
      character, intent(in), optional       :: init
      real(psb_spk_),intent(inout), optional :: initu(:)
    end subroutine amg_s_slu_solver_apply
  end interface

contains

!!$  subroutine s_slu_solver_apply(alpha,sv,x,beta,y,desc_data,&
!!$       & trans,work,info,init,initu)
!!$    use psb_base_mod
!!$    implicit none 
!!$    type(psb_desc_type), intent(in)      :: desc_data
!!$    class(amg_s_slu_solver_type), intent(inout) :: sv
!!$    real(psb_spk_),intent(inout)         :: x(:)
!!$    real(psb_spk_),intent(inout)         :: y(:)
!!$    real(psb_spk_),intent(in)            :: alpha,beta
!!$    character(len=1),intent(in)          :: trans
!!$    real(psb_spk_),target, intent(inout) :: work(:)
!!$    integer, intent(out)                 :: info
!!$    character, intent(in), optional       :: init
!!$    real(psb_spk_),intent(inout), optional :: initu(:)
!!$
!!$    integer    :: n_row,n_col
!!$    real(psb_spk_), pointer :: ww(:)
!!$    type(psb_ctxt_type) :: ctxt
!!$    integer    :: np,me,i, err_act
!!$    character          :: trans_
!!$    character(len=20)  :: name='s_slu_solver_apply'
!!$
!!$    call psb_erractionsave(err_act)
!!$
!!$    info = psb_success_
!!$
!!$    trans_ = psb_toupper(trans)
!!$    select case(trans_)
!!$    case('N')
!!$    case('T','C')
!!$    case default
!!$      call psb_errpush(psb_err_iarg_invalid_i_,name)
!!$      goto 9999
!!$    end select
!!$    !
!!$    ! For non-iterative solvers, init and initu are ignored.
!!$    !
!!$
!!$    n_row = desc_data%get_local_rows()
!!$    n_col = desc_data%get_local_cols()
!!$
!!$    if (n_col <= size(work)) then 
!!$      ww => work(1:n_col)
!!$    else
!!$      allocate(ww(n_col),stat=info)
!!$      if (info /= psb_success_) then 
!!$        info=psb_err_alloc_request_
!!$        call psb_errpush(info,name,i_err=(/n_col,0,0,0,0/),&
!!$             & a_err='real(psb_spk_)')
!!$        goto 9999      
!!$      end if
!!$    endif
!!$
!!$    ww(1:n_row) = x(1:n_row)
!!$    select case(trans_)
!!$    case('N')
!!$      info = amg_sslu_solve(0,n_row,1,ww,n_row,sv%lufactors)
!!$    case('T')
!!$      info = amg_sslu_solve(1,n_row,1,ww,n_row,sv%lufactors)
!!$    case('C')
!!$      info = amg_sslu_solve(2,n_row,1,ww,n_row,sv%lufactors)
!!$    case default
!!$      call psb_errpush(psb_err_internal_error_, &
!!$           & name,a_err='Invalid TRANS in ILU subsolve')
!!$      goto 9999
!!$    end select
!!$
!!$    if (info == psb_success_) &
!!$         & call psb_geaxpby(alpha,ww,beta,y,desc_data,info)
!!$
!!$
!!$    if (info /= psb_success_) then
!!$      call psb_errpush(psb_err_internal_error_,& 
!!$           & name,a_err='Error in subsolve')
!!$      goto 9999
!!$    endif
!!$
!!$    if (n_col > size(work)) then 
!!$      deallocate(ww)
!!$    endif
!!$
!!$    call psb_erractionrestore(err_act)
!!$    return
!!$
!!$9999 call psb_error_handler(err_act)
!!$    return
!!$
!!$  end subroutine s_slu_solver_apply
!!$  
!!$  subroutine s_slu_solver_apply_vect(alpha,sv,x,beta,y,desc_data,&
!!$       & trans,work,wv,info,init,initu)
!!$    use psb_base_mod
!!$    implicit none 
!!$    type(psb_desc_type), intent(in)      :: desc_data
!!$    class(amg_s_slu_solver_type), intent(inout) :: sv
!!$    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
!!$    real(psb_spk_),target, intent(inout) :: work(:)
!!$    type(psb_s_vect_type),intent(inout) :: wv(:)
!!$    integer, intent(out)                  :: info
!!$    character, intent(in), optional                :: init
!!$    type(psb_s_vect_type),intent(inout), optional   :: initu
!!$
!!$    integer    :: err_act
!!$    character(len=20)  :: name='s_slu_solver_apply_vect'
!!$
!!$    call psb_erractionsave(err_act)
!!$
!!$    info = psb_success_
!!$    !
!!$    ! For non-iterative solvers, init and initu are ignored.
!!$    !
!!$
!!$    call x%v%sync()
!!$    call y%v%sync()
!!$    call sv%apply(alpha,x%v%v,beta,y%v%v,desc_data,trans,work,info)
!!$    call y%v%set_host()
!!$    if (info /= 0) goto 9999
!!$
!!$    call psb_erractionrestore(err_act)
!!$    return
!!$
!!$9999 call psb_error_handler(err_act)
!!$    return
!!$  
!!$  end subroutine s_slu_solver_apply_vect
!!$
!!$  subroutine s_slu_solver_bld(a,desc_a,sv,info,b,amold,vmold,imold)
!!$
!!$    use psb_base_mod
!!$
!!$    Implicit None
!!$
!!$    ! Arguments
!!$    type(psb_sspmat_type), intent(in), target           :: a
!!$    Type(psb_desc_type), Intent(inout)                  :: desc_a 
!!$    class(amg_s_slu_solver_type), intent(inout)         :: sv
!!$    integer, intent(out)                                :: info
!!$    type(psb_sspmat_type), intent(in), target, optional :: b
!!$    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
!!$    ! Local variables
!!$    type(psb_sspmat_type) :: atmp
!!$    type(psb_s_csc_sparse_mat) :: acsc
!!$    type(psb_s_coo_sparse_mat) :: acoo
!!$    integer :: n_row,n_col, nrow_a, nztota
!!$    type(psb_ctxt_type) :: ctxt
!!$    integer :: np,me,i, err_act, debug_unit, debug_level
!!$    character(len=20)  :: name='s_slu_solver_bld', ch_err
!!$    
!!$    info=psb_success_
!!$    call psb_erractionsave(err_act)
!!$    debug_unit  = psb_get_debug_unit()
!!$    debug_level = psb_get_debug_level()
!!$    ctxt       = desc_a%get_context()
!!$    call psb_info(ctxt, me, np)
!!$    if (debug_level >= psb_debug_outer_) &
!!$         & write(debug_unit,*) me,' ',trim(name),' start'
!!$    
!!$    
!!$    n_row  = desc_a%get_local_rows()
!!$    n_col  = desc_a%get_local_cols()
!!$    
!!$    
!!$    call a%cscnv(atmp,info,type='coo')
!!$    call psb_rwextd(n_row,atmp,info,b=b) 
!!$    call atmp%cscnv(info,type='coo',dupl=psb_dupl_add_)
!!$    nrow_a = atmp%get_nrows()
!!$    call atmp%a%csclip(acoo,info,jmax=nrow_a)
!!$    call acsc%mv_from_coo(acoo,info)
!!$    nztota = acsc%get_nzeros()
!!$    ! Fix the entries to call C-base SuperLU
!!$    acsc%ia(:)  = acsc%ia(:)  - 1
!!$    acsc%icp(:) = acsc%icp(:) - 1
!!$    info = amg_sslu_fact(nrow_a,nztota,acsc%val,&
!!$         & acsc%icp,acsc%ia,sv%lufactors)
!!$    
!!$    if (info /= psb_success_) then
!!$      info=psb_err_from_subroutine_
!!$      ch_err='amg_sslu_fact'
!!$      call psb_errpush(info,name,a_err=ch_err)
!!$      goto 9999
!!$    end if
!!$    
!!$    call acsc%free()
!!$    call atmp%free()
!!$
!!$    if (debug_level >= psb_debug_outer_) &
!!$         & write(debug_unit,*) me,' ',trim(name),' end'
!!$
!!$    call psb_erractionrestore(err_act)
!!$    return
!!$
!!$9999 call psb_error_handler(err_act)
!!$    return
!!$  end subroutine s_slu_solver_bld

  subroutine s_slu_solver_free(sv,info)

    Implicit None

    ! Arguments
    class(amg_s_slu_solver_type), intent(inout) :: sv
    integer, intent(out)                       :: info
    Integer :: err_act
    character(len=20)  :: name='s_slu_solver_free'

    call psb_erractionsave(err_act)

    info = psb_success_ 

    call sv%clear_data(info)

    if (info /= psb_success_) goto 9999

    call psb_erractionrestore(err_act)
    return

9999 call psb_error_handler(err_act)
  return
  end subroutine s_slu_solver_free

  subroutine s_slu_solver_clear_data(sv,info)

    Implicit None

    ! Arguments
    class(amg_s_slu_solver_type), intent(inout) :: sv
    integer, intent(out)                       :: info
    Integer :: err_act
    character(len=20)  :: name='s_slu_solver_clear_data'

    call psb_erractionsave(err_act)

    info = psb_success_ 
    if (c_associated(sv%lufactors)) info = amg_sslu_free(sv%lufactors)
    sv%lufactors = c_null_ptr
    if (info /= psb_success_) goto 9999

    call psb_erractionrestore(err_act)
    return

9999 call psb_error_handler(err_act)
    return
  end subroutine s_slu_solver_clear_data

  subroutine s_slu_solver_finalize(sv)

    Implicit None

    ! Arguments
    type(amg_s_slu_solver_type), intent(inout) :: sv
    integer :: info
    Integer :: err_act
    character(len=20)  :: name='s_slu_solver_finalize'

    call sv%free(info) 

    return
  
  end subroutine s_slu_solver_finalize

  subroutine s_slu_solver_descr(sv,info,iout,coarse,prefix)

    Implicit None

    ! Arguments
    class(amg_s_slu_solver_type), intent(in) :: sv
    integer, intent(out)                       :: info
    integer, intent(in), optional              :: iout
    logical, intent(in), optional              :: coarse
    character(len=*), intent(in), optional     :: prefix

    ! Local variables
    integer      :: err_act
    character(len=20), parameter :: name='amg_s_slu_solver_descr'
    integer :: iout_
    character(1024)    :: prefix_

    call psb_erractionsave(err_act)
    info = psb_success_
    if (present(iout)) then 
      iout_ = iout 
    else
      iout_ = psb_out_unit
    endif
    if (present(prefix)) then
      prefix_ = prefix
    else
      prefix_ = ""
    end if
    
    write(iout_,*) trim(prefix_), '  SuperLU Sparse Factorization Solver. '

    call psb_erractionrestore(err_act)
    return

9999 call psb_error_handler(err_act)
    return
  end subroutine s_slu_solver_descr

  function s_slu_solver_sizeof(sv) result(val)

    implicit none 
    ! Arguments
    class(amg_s_slu_solver_type), intent(in) :: sv
    integer(psb_epk_) :: val
    integer             :: i

    val = 2*psb_sizeof_ip + psb_sizeof_dp
    val = val + sv%symbsize
    val = val + sv%numsize
    return
  end function s_slu_solver_sizeof

  function s_slu_solver_get_fmt() result(val)
    implicit none 
    character(len=32)  :: val

    val = "SuperLU solver"
  end function s_slu_solver_get_fmt

  function s_slu_solver_get_id() result(val)
    implicit none 
    integer(psb_ipk_)  :: val

    val = amg_slu_
  end function s_slu_solver_get_id
#endif
end module amg_s_slu_solver
