psblas3/base/tools/psb_cdals.f90

!   
!                Parallel Sparse BLAS  version 3.5
!      (C) Copyright 2006-2018
!        Salvatore Filippone    
!        Alfredo Buttari      
!   
!    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
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!    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
!    POSSIBILITY OF SUCH DAMAGE.
!   
!    
! File: psb_cdals.f90
!
! Subroutine: psb_cdals
!    Allocate descriptor
!    and checks correctness of PARTS subroutine
! 
! Arguments: 
!    m       - integer.                       The number of rows.
!    n       - integer.                       The number of columns.
!    parts   - external subroutine.           The routine that contains the 
!                                                 partitioning scheme.
!    ictxt - integer.                         The communication context.
!    desc  - type(psb_desc_type).         The communication descriptor.
!    info    - integer.                       Error code (if any).
subroutine psb_cdals(m, n, parts, ictxt, desc, info)
  use psb_base_mod
  use psi_mod
  use psb_repl_map_mod
  use psb_list_map_mod
  use psb_hash_map_mod
  implicit None
  procedure(psb_parts)             :: parts
  !....Parameters...
  integer(psb_lpk_), intent(in)    :: M,N
  type(psb_ctxt_type), intent(in)  :: ictxt
  Type(psb_desc_type), intent(out) :: desc
  integer(psb_ipk_), intent(out)   :: info

  !locals
  integer(psb_ipk_) :: counter,i,j,loc_row,err,loc_col,&
       & l_ov_ix,l_ov_el,idx, err_act, itmpov, k, glx, nlx
  integer(psb_lpk_) :: iglob
  integer(psb_ipk_) :: exch(3)
  integer(psb_ipk_), allocatable  :: temp_ovrlap(:)
  integer(psb_lpk_), allocatable  :: l_temp_ovrlap(:), loc_idx(:)
  integer(psb_ipk_), allocatable  :: prc_v(:)
  integer(psb_ipk_) :: debug_level, debug_unit
  integer(psb_ipk_) :: me, np, nprocs
  character(len=20)    :: name

  if(psb_get_errstatus() /= 0) return 
  info=psb_success_
  err=0
  name = 'psb_cdall'
  call psb_erractionsave(err_act)
  debug_unit  = psb_get_debug_unit()
  debug_level = psb_get_debug_level()

  call psb_info(ictxt, me, np)
  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),': ',np
  !     ....verify blacs grid correctness..
  
  !... check m and n parameters....
  if (m < 1) then
    info = psb_err_iarg_neg_
    err=info
    call psb_errpush(err,name,l_err=(/lone,m/))
    goto 9999
  else if (n < 1) then
    info = psb_err_iarg_neg_
    err=info
    call psb_errpush(err,name,l_err=(/lone*2,n/))
    goto 9999
  endif

  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),':  doing global checks'  
  !global check on m and n parameters
  if (me == psb_root_) then
    exch(1)=m; exch(2)=n; exch(3)=psb_cd_get_large_threshold()
    call psb_bcast(ictxt,exch(1:3),root=psb_root_)
  else
    call psb_bcast(ictxt,exch(1:3),root=psb_root_)
    if (exch(1) /= m) then
      err=550
      call psb_errpush(err,name,m_err=(/1/))
      goto 9999
    else if (exch(2) /= n) then
      err=550
      call psb_errpush(err,name,m_err=(/2/))
      goto 9999
    endif
    call psb_cd_set_large_threshold(exch(3))
  endif

  call psb_nullify_desc(desc)

  ! count local rows number
  loc_row = max(1,(m+np-1)/np) 
  ! allocate work vector
  allocate(l_temp_ovrlap(max(1,2*loc_row)), prc_v(np),stat=info)

  if (info /= psb_success_) then     
    info=psb_err_alloc_request_
    err=info
    call psb_errpush(err,name,a_err='integer',l_err=(/2*m+psb_mdata_size_+np/))
    goto 9999
  endif

  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),':  starting main loop' ,info
  counter = 0
  itmpov  = 0
  l_temp_ovrlap(:) = -1
  !
  ! We have to decide whether we have a "large" index space.
  !

  !
  ! Yes, we do have a large index space. Therefore we are 
  ! keeping on the local process a map of only the global 
  ! indices ending up here; this map is stored partly in
  ! a hash of sorted lists, part in a hash table.
  ! At assembly time 
  ! is transferred to a series of ordered linear lists, 
  ! hashed by the low order bits of the entries.
  !
  loc_col = max(1,(m+np-1)/np)
  loc_col = min(2*loc_col,m)

  allocate(desc%lprm(1), loc_idx(loc_col), stat=info)  
  if (info == psb_success_) then 
    if (np == 1) then 
      allocate(psb_repl_map :: desc%indxmap, stat=info)
    else
      allocate(psb_hash_map :: desc%indxmap, stat=info)
      desc%indxmap%parts => parts
    end if
  end if

  if (info /= psb_success_) then
    info=psb_err_alloc_request_
    call psb_errpush(info,name,i_err=(/loc_col/),a_err='integer')
    goto 9999
  end if

  ! set LOC_TO_GLOB array to all "-1" values
  desc%lprm(1) = 0

  k = 0
  do iglob=1,m
    if (info == psb_success_) then
      call parts(iglob,m,np,prc_v,nprocs)
      if (nprocs > np) then
        info=psb_err_partfunc_toomuchprocs_
        call psb_errpush(info,name,l_err=(/3_psb_lpk_,np*lone,nprocs*lone,iglob/))
        goto 9999
      else if (nprocs <= 0) then
        info=psb_err_partfunc_toofewprocs_
        call psb_errpush(info,name,l_err=(/3_psb_lpk_,nprocs*lone,iglob/))
        goto 9999
      else
        do j=1,nprocs
          if ((prc_v(j) > np-1).or.(prc_v(j) < 0)) then
            info=psb_err_partfunc_wrong_pid_
            call psb_errpush(info,name,l_err=(/3_psb_lpk_,prc_v(j)*lone,iglob/))
            goto 9999
          end if
        end do
      endif
      j=1
      do 
        if (j > nprocs) exit
        if (prc_v(j) == me) exit
        j=j+1
      enddo

      if (j <= nprocs) then 
        if (prc_v(j) == me) then
          ! this point belongs to me
          k = k + 1 
          call psb_ensure_size((k+1),loc_idx,info,pad=-1_psb_lpk_)
          if (info /= psb_success_) then
            info=psb_err_from_subroutine_
            call psb_errpush(info,name,a_err='psb_ensure_size')
            goto 9999
          end if
          loc_idx(k) = iglob

          if (nprocs > 1)  then
            call psb_ensure_size((itmpov+3+nprocs),l_temp_ovrlap,info,pad=-1_psb_lpk_)
            if (info /= psb_success_) then
              info=psb_err_from_subroutine_
              call psb_errpush(info,name,a_err='psb_ensure_size')
              goto 9999
            end if
            itmpov = itmpov + 1
            l_temp_ovrlap(itmpov) = iglob
            itmpov = itmpov + 1
            l_temp_ovrlap(itmpov) = nprocs
            l_temp_ovrlap(itmpov+1:itmpov+nprocs) = prc_v(1:nprocs)
            itmpov = itmpov + nprocs
          endif
        end if
      end if
    end if
  enddo
  if (info /= psb_success_) then 
    info=psb_err_alloc_dealloc_
    call psb_errpush(info,name)
    goto 9999
  endif
  loc_row = k 

  ! check on parts function
  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),':  End main loop:' ,loc_row,itmpov,info

  select type(aa => desc%indxmap) 
  type is (psb_repl_map) 
    call aa%repl_map_init(ictxt,m,info)
  class default 
    call aa%init(ictxt,loc_idx(1:k),info)
  end select


  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),':  error check:' ,err
  !
  ! Now that we have initialized indxmap we can convert the
  ! indices to local numbering.
  !
  block
    integer(psb_ipk_) :: i,nprocs
    allocate(temp_ovrlap(size(l_temp_ovrlap)),stat=info)
    if (info == psb_success_) then 
      temp_ovrlap = -1
      i = 1
      do while (l_temp_ovrlap(i) /= -1) 
        call desc%indxmap%g2l(l_temp_ovrlap(i),temp_ovrlap(i),info)
        i              = i + 1
        temp_ovrlap(i) = l_temp_ovrlap(i)
        nprocs         = temp_ovrlap(i)
        temp_ovrlap(i+1:i+nprocs) = l_temp_ovrlap(i+1:i+nprocs)
        i       = i + 1
        i       = i + nprocs     
      enddo
    end if
  end block
  if (info == psb_success_) call psi_bld_tmpovrl(temp_ovrlap,desc,info)

  if (info == psb_success_) deallocate(prc_v,temp_ovrlap,stat=info)
  if (info /= psb_no_err_) then 
    info=psb_err_alloc_dealloc_
    err=info
    call psb_errpush(err,name)
    Goto 9999
  endif

  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),': end'

  call psb_erractionrestore(err_act)
  return

9999 call psb_error_handler(ictxt,err_act)

  return

end subroutine psb_cdals