psblas3/base/tools/psb_cdalv.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:
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!      2. Redistributions in binary form must reproduce the above copyright
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!      3. The name of the PSBLAS group or the names of its contributors may
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!         software without specific written permission.
!   
!    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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!   
!    
! File: psb_cdalv.f90
!
! Subroutine: psb_cdalv
!    Allocate descriptor by means of a global map vector V: index I 
!    is assigned to process V(I). It is assumed that V is identical 
!    on all calling processes.
!    
! 
! Arguments: 
!    v       - integer(psb_ipk_), dimension(:).         The array containg the partitioning scheme.
!    ctxt - integer.                         The communication context.
!    desc  - type(psb_desc_type).         The communication descriptor.
!    info    - integer.                       Return code
!    flag    - integer.                       Are V's contents 0- or 1-based?
subroutine psb_cdalv(v, ctxt, desc, info, flag)
  use psb_base_mod
  use psi_mod
  use psb_repl_map_mod
  use psb_glist_map_mod
  use psb_hash_map_mod
  implicit None
  !....Parameters...
  type(psb_ctxt_type)                      :: ctxt
  integer(psb_ipk_), intent(in)            :: v(:)
  integer(psb_ipk_), intent(in), optional  :: flag
  integer(psb_ipk_), intent(out)           :: info
  type(psb_desc_type), intent(out)  :: desc

  !locals
  integer(psb_ipk_) :: counter,j,np,me,loc_row,err,&
       & loc_col,nprocs,itmpov, k,glx,&
       & l_ov_ix,l_ov_el,idx, flag_, err_act
  integer(psb_lpk_) :: m,n,i,exch(3)
  integer(psb_lpk_) :: l_err(5)
  integer(psb_ipk_), allocatable  :: temp_ovrlap(:)
  integer(psb_ipk_) :: debug_level, debug_unit
  character(len=20)  :: name

  if(psb_get_errstatus() /= 0) return 
  debug_unit  = psb_get_debug_unit()
  debug_level = psb_get_debug_level()
  info = psb_success_
  err  = 0
  name = 'psb_cdalv'

  call psb_info(ctxt, me, np)
  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),': ',np,me
  m = size(v)
  n = m
  !... check m and n parameters....
  if (m < 1) then
    info = psb_err_iarg_neg_
    l_err(1) = 1
    l_err(2) = m
  else if (n < 1) then
    info = psb_err_iarg_neg_
    l_err(1) = 2
    l_err(2) = n
  else if (size(v)<m) then 
    info = psb_err_iarg_neg_
    l_err(1) = 2
    l_err(2) = size(v)
  endif

  if (info /= psb_success_) then 
    call psb_errpush(info,name,l_err=l_err)
    goto 9999
  end if

  if (me == psb_root_) then
    exch(1)=m
    exch(2)=n
    exch(3)=psb_cd_get_large_threshold()
    call psb_bcast(ctxt,exch(1:3),root=psb_root_)
  else
    call psb_bcast(ctxt,exch(1:3),root=psb_root_)
    if (exch(1) /= m) then
      err=550
      l_err(1)=1
      call psb_errpush(err,name,l_err=l_err)
      goto 9999
    else if (exch(2) /= n) then
      err=550
      l_err(1)=2
      call psb_errpush(err,name,l_err=l_err)
      goto 9999
    endif
    call psb_cd_set_large_threshold(exch(3))
  endif

  call psb_nullify_desc(desc)

  if (present(flag)) then
    flag_=flag
  else
    flag_=0
  endif

  if ((flag_<0).or.(flag_>1)) then
    info = 6
    call psb_errpush(info,name)
    goto 9999
  end if

  ! count local rows number
  loc_row = max(1,(m+np-1)/np) 
  ! allocate work vector
  allocate(temp_ovrlap(2),stat=info)
  if (info /= psb_success_) then     
    info=psb_err_alloc_request_
    l_err(1)=2*m+psb_mdata_size_
    call psb_errpush(info,name,l_err=l_err,a_err='integer')
    goto 9999
  endif

  if (debug_level >= psb_debug_ext_) &
       & write(debug_unit,*) me,' ',trim(name),':  starting main loop' ,info
  counter = 0
  itmpov  = 0
  temp_ovrlap(:) = -1

  !$omp parallel do private(i) reduction(+:counter)
  do i=1,m

    if (((v(i)-flag_) > np-1).or.((v(i)-flag_) < 0)) then
      info=psb_err_partfunc_wrong_pid_
      l_err(1)=3
      l_err(2)=v(i) - flag_
      l_err(3)=i
      !exit
    end if

    if ((v(i)-flag_) == me) then
      ! this point belongs to me
      counter=counter+1
    end if
  enddo
  if (info /= psb_success_) then     
    call psb_errpush(info,name,l_err=l_err)
    goto 9999
  endif
  
  loc_row=counter

  !
  ! We have to decide whether we have a "large" index space.
  !
  if (np == 1) then 
    allocate(psb_repl_map :: desc%indxmap, stat=info)
  else
    if (psb_cd_choose_large_state(ctxt,m)) then 
      allocate(psb_hash_map :: desc%indxmap, stat=info)
      if (info == 0) allocate(desc%indxmap%tempvg(m),stat=info)
      if (info ==0) desc%indxmap%tempvg(1:m) = v(1:m) - flag_
    else 
      allocate(psb_glist_map :: desc%indxmap, stat=info)
    end if
  end if


  select type(aa => desc%indxmap) 
  type is (psb_repl_map) 
    call aa%repl_map_init(ctxt,m,info)
  type is (psb_hash_map) 
    call aa%hash_map_init(ctxt,v,info)
  type is (psb_glist_map) 
    call aa%glist_map_init(ctxt,v,info)
  class default 
      ! This cannot happen 
    info = psb_err_internal_error_
    call psb_errpush(info,name)
    Goto 9999
  end select


  call psi_bld_tmpovrl(temp_ovrlap,desc,info)

  deallocate(temp_ovrlap,stat=info)
  if (info /= psb_success_) then 
    info=psb_err_alloc_dealloc_
    call psb_errpush(info,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(ctxt,err_act)

  return

end subroutine psb_cdalv