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spclibs/multigrid/src/partition.f90
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partition.f90
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!>
!> @file partition.f90
!>
!> @brief
!>
!> @copyright
!> Copyright (©) 2021 EPFL (Ecole Polytechnique Fédérale de Lausanne)
!> SPC (Swiss Plasma Center)
!>
!> spclibs is free software: you can redistribute it and/or modify it under
!> the terms of the GNU Lesser General Public License as published by the Free
!> Software Foundation, either version 3 of the License, or (at your option)
!> any later version.
!>
!> spclibs is distributed in the hope that it will be useful, but WITHOUT ANY
!> WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
!> FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
!>
!> You should have received a copy of the GNU Lesser General Public License
!> along with this program. If not, see <https://www.gnu.org/licenses/>.
!>
!> @authors
!> (in alphabetical order)
!> @author Trach-Minh Tran <trach-minh.tran@epfl.ch>
!>
PROGRAM main
USE mpi
USE pputils2, ONLY : dist1d
USE parmg, ONLY : get_lmax, coarse, disp
IMPLICIT NONE
!
INTEGER :: me, npes, ierr
INTEGER :: n, npt, npt_loc, s, e
INTEGER :: l, lmax
!
CALL MPI_INIT(ierr)
CALL MPI_COMM_RANK(MPI_COMM_WORLD, me, ierr)
CALL MPI_COMM_SIZE(MPI_COMM_WORLD, npes, ierr)
!
IF(me.EQ.0) THEN
WRITE(*,*) 'Enter n'
READ(*,*) n
END IF
CALL mpi_bcast(n,1,MPI_INTEGER, 0, MPI_COMM_WORLD, ierr)
!
! Partition ot finest grid
!
npt = n+1
CALL dist1d(MPI_COMM_WORLD, 0, npt, s, npt_loc)
e = s+npt_loc-1
CALL disp('start index=', s, MPI_COMM_WORLD)
!
! Max number of levels
!
lmax = get_lmax(s, npt_loc, 1, MPI_COMM_WORLD)
IF(me.EQ.0) WRITE(*,'(a,i0)') 'Max number of levels ', lmax
!
! Grid coarsening
!
DO l=1,lmax
IF(l.GT.1) THEN
CALL coarse(s, e)
npt_loc = e-s+1
CALL mpi_allreduce(npt_loc, npt, 1, MPI_INTEGER, MPI_SUM, &
& MPI_COMM_WORLD, ierr)
END IF
IF(me.EQ.0) WRITE(*, '(a,i3)') 'level', l
CALL disp('s ', s, MPI_COMM_WORLD)
CALL disp('e ', e, MPI_COMM_WORLD)
CALL disp('npt_loc', npt_loc, MPI_COMM_WORLD)
CALL disp('npt ', npt, MPI_COMM_WORLD)
END DO
!
CALL MPI_FINALIZE(ierr)
!
!+++++
END PROGRAM main
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