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psblas3/base/internals/psi_fnd_owner.f90

169 lines
5.3 KiB
Fortran

!!$
!!$ Parallel Sparse BLAS version 2.2
!!$ (C) Copyright 2006/2007/2008
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari University of Rome Tor Vergata
!!$
!!$ 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
!!$ PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS 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.
!!$
!!$
!
! File: psi_fnd_owner.f90
!
! Subroutine: psi_fnd_owner
! Figure out who owns global indices.
!
! Arguments:
! nv - integer Number of indices required on the calling
! process
! idx(:) - integer Required indices on the calling process
! iprc(:) - integer, allocatable Output: process identifiers for the corresponding
! indices
! desc_a - type(psb_desc_type). The communication descriptor.
! info - integer. return code.
!
subroutine psi_fnd_owner(nv,idx,iprc,desc,info)
use psb_descriptor_type
use psb_serial_mod
use psb_const_mod
use psb_error_mod
use psb_penv_mod
use psb_realloc_mod
use psi_mod, psb_protect_name => psi_fnd_owner
implicit none
integer, intent(in) :: nv
integer, intent(in) :: idx(:)
integer, allocatable, intent(out) :: iprc(:)
type(psb_desc_type), intent(in) :: desc
integer, intent(out) :: info
integer,allocatable :: hsz(:),hidx(:),helem(:),hproc(:)
integer :: i,n_row,n_col, err_act,ih,icomm,hsize
integer :: ictxt,np,me
character(len=20) :: name
info = 0
name = 'psi_fnd_owner'
call psb_erractionsave(err_act)
ictxt = psb_cd_get_context(desc)
icomm = psb_cd_get_mpic(desc)
n_row = psb_cd_get_local_rows(desc)
n_col = psb_cd_get_local_cols(desc)
! check on blacs grid
call psb_info(ictxt, me, np)
if (np == -1) then
info = 2010
call psb_errpush(info,name)
goto 9999
endif
if (nv < 0 ) then
info = 2010
call psb_errpush(info,name)
goto 9999
endif
if (.not.(psb_is_ok_desc(desc))) then
call psb_errpush(4010,name,a_err='invalid desc')
goto 9999
end if
!
! The basic idea is very simple.
! First we figure out the total number of requests.
Allocate(hidx(np+1),hsz(np),stat=info)
if (info /= 0) then
call psb_errpush(4010,name,a_err='Allocate')
goto 9999
end if
hsz = 0
hsz(me+1) = nv
call psb_amx(ictxt,hsz,info)
hidx(1) = 1
do i=1, np
hidx(i+1) = hidx(i) + hsz(i)
end do
hsize = hidx(np+1)-1
Allocate(helem(hsize),hproc(hsize),stat=info)
if (info /= 0) then
call psb_errpush(4010,name,a_err='Allocate')
goto 9999
end if
! Second we build the aggregate list of requests (with psb_amx)
helem(:) = 0
ih = hidx(me+1)
do i=1, hsz(me+1)
helem(ih+i-1) = idx(i)
end do
call psb_amx(ictxt,helem,info)
! Third, we figure out locally whether we own the indices (whoever is
! asking for them) and build our part of the reply (we shift process
! indices so that they're 1-based)
call psi_idx_cnv(hsize,helem,desc,info,owned=.true.)
if (info /= 0) then
call psb_errpush(4010,name,a_err='psi_idx_cnv')
goto 9999
end if
do i=1,hsize
if ((0< helem(i)).and. (helem(i) <= n_row))then
hproc(i) = me+1
else
hproc(i) = 0
end if
end do
! Fourth, we do a psb_amx on the replies so that we have everybody's answers
call psb_amx(ictxt,hproc,info)
! Fifth, we extract the answers for our local query, and shift back the
! process indices to 0-based.
call psb_realloc(nv,iprc,info)
ih = hidx(me+1)
do i=1, hsz(me+1)
iprc(i) = hproc(ih+i-1) - 1
end do
call psb_erractionrestore(err_act)
return
9999 continue
call psb_erractionrestore(err_act)
if (err_act == psb_act_ret_) then
return
else
call psb_error(ictxt)
end if
return
end subroutine psi_fnd_owner