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OpenMPI Sample Applications

Sample MPI applications provided both as a trivial primer to MPI as well as simple tests to ensure that your OpenMPI installation is working properly.

Examples

There are two MPI examples, each using one of six different MPI interfaces:

Hello World

```c tab="C" / * Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana * University Research and Technology * Corporation. All rights reserved. * Copyright (c) 2006 Cisco Systems, Inc. All rights reserved. * * Sample MPI "hello world" application in C /

include

include "mpi.h"

int main(int argc, char* argv[]) { int rank, size, len; char version[MPI_MAX_LIBRARY_VERSION_STRING];

MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Get_library_version(version, &len);
printf("Hello, world, I am %d of %d, (%s, %d)\n",
       rank, size, version, len);
MPI_Finalize();

return 0;

} c++ tab="C++" // // Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana // University Research and Technology // Corporation. All rights reserved. // Copyright (c) 2006 Cisco Systems, Inc. All rights reserved. // // Sample MPI "hello world" application in C++ // // NOTE: The MPI C++ bindings were deprecated in MPI-2.2 and removed // from the standard in MPI-3. Open MPI still provides C++ MPI // bindings, but they are no longer built by default (and may be // removed in a future version of Open MPI). You must // --enable-mpi-cxx when configuring Open MPI to enable the MPI C++ // bindings. //

include "mpi.h"

include

int main(int argc, char **argv) { int rank, size, len; char version[MPI_MAX_LIBRARY_VERSION_STRING]; MPI::Init(); rank = MPI::COMM_WORLD.Get_rank(); size = MPI::COMM_WORLD.Get_size(); MPI_Get_library_version(version, &len); std::cout << "Hello, world! I am " << rank << " of " << size << "(" << version << ", " << len << ")" << std::endl; MPI::Finalize(); return 0; } ```

```fortran tab="F mpi.h" C C Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana C University Research and Technology C Corporation. All rights reserved. C Copyright (c) 2006-2015 Cisco Systems, Inc. All rights reserved. C COPYRIGHT C C Sample MPI "hello world" application using the Fortran mpif.h C bindings. C program main implicit none include 'mpif.h' integer ierr, rank, size, len character(len=MPI_MAX_LIBRARY_VERSION_STRING) version

    call MPI_INIT(ierr)
    call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
    call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr)
    call MPI_GET_LIBRARY_VERSION(version, len, ierr)

    write(*, '("Hello, world, I am ", i2, " of ", i2, ": ", a)')
 &        rank, size, version

    call MPI_FINALIZE(ierr)

    end

fortran tab="F use mpi" ! ! Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana ! University Research and Technology ! Corporation. All rights reserved. ! Copyright (c) 2004-2005 The Regents of the University of California. ! All rights reserved. ! Copyright (c) 2006-2015 Cisco Systems, Inc. All rights reserved. ! COPYRIGHT ! ! Sample MPI "hello world" application using the Fortran mpi module ! bindings. ! program main use mpi implicit none integer :: ierr, rank, size, len character(len=MPI_MAX_LIBRARY_VERSION_STRING) :: version call MPI_INIT(ierr) call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr) call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr) call MPI_GET_LIBRARY_VERSION(version, len, ierr) write(*, '("Hello, world, I am ", i2, " of ", i2, ": ", a)') & rank, size, version call MPI_FINALIZE(ierr) end ```

```java tab="Java" /* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

/ / * Author of revised version: Franklyn Pinedo * * Adapted from Source Code in C of Tutorial/User's Guide for MPI by * Peter Pacheco. / / * Copyright (c) 2011 Cisco Systems, Inc. All rights reserved. * */

import mpi.*;

class Hello { static public void main(String[] args) throws MPIException {

MPI.Init(args);

int myrank = MPI.COMM_WORLD.getRank();
int size = MPI.COMM_WORLD.getSize() ;
System.out.println("Hello world from rank " + myrank + " of " + size);

MPI.Finalize();
}

} ``` * C: hello_c.c * C++: hello_cxx.cc * Fortran mpif.h: hello_mpifh.f * Fortran use mpi: hello_usempi.f90 * Fortran use mpi_f08: hello_usempif08.f90 * Java: Hello.java * C shmem.h: hello_oshmem_c.c * Fortran shmem.fh: hello_oshmemfh.f90

Send a Trivial Message Around in a Ring

Test the Connectivity Between All Pross

Build Examples

Download examples. The Makefile in this directory will build the examples for the supported languages (e.g., if you do not have the Fortran "use mpi" bindings compiled as part of OpenMPI, those examples will be skipped). The Makefile assumes that the wrapper compilers mpicc, mpic++, and mpifort are in your path. Although the Makefile is tailored for OpenMPI (e.g., it checks the mpi_info command to see if you have support for C++, mpif.h, use mpi, and use mpi_f08 F90), all of the example programs are pure MPI, and therefore not specific to OpenMPI. Hence, you can use a different MPI implementation to compile and run these programs if you wish. console [login@cn204.anselm ]$ tar xvf ompi.tar.gz ./ ./connectivity_c.c ./Hello.java ./ring_mpifh.f ./hello_oshmem_cxx.cc ... ... ./hello_cxx.cc [login@cn204.anselm ]$ ml OpenMPI/2.1.1-GCC-6.3.0-2.27 [login@cn204.anselm ]$ make mpicc -g hello_c.c -o hello_c mpicc -g ring_c.c -o ring_c mpicc -g connectivity_c.c -o connectivity_c mpicc -g spc_example.c -o spc_example mpic++ -g hello_cxx.cc -o hello_cxx mpic++ -g ring_cxx.cc -o ring_cxx mpifort -g hello_mpifh.f -o hello_mpifh mpifort -g ring_mpifh.f -o ring_mpifh mpifort -g hello_usempi.f90 -o hello_usempi mpifort -g ring_usempi.f90 -o ring_usempi mpifort -g hello_usempif08.f90 -o hello_usempif08 mpifort -g ring_usempif08.f90 -o ring_usempif08 mpijavac Hello.java mpijavac Ring.java shmemcc -g hello_oshmem_c.c -o hello_oshmem shmemc++ -g hello_oshmem_cxx.cc -o hello_oshmemcxx shmemcc -g ring_oshmem_c.c -o ring_oshmem shmemcc -g oshmem_shmalloc.c -o oshmem_shmalloc shmemcc -g oshmem_circular_shift.c -o oshmem_circular_shift shmemcc -g oshmem_max_reduction.c -o oshmem_max_reduction shmemcc -g oshmem_strided_puts.c -o oshmem_strided_puts shmemcc -g oshmem_strided_puts.c -o oshmem_strided_puts shmemcc -g oshmem_symmetric_data.c -o oshmem_symmetric_data shmemfort -g hello_oshmemfh.f90 -o hello_oshmemfh shmemfort -g ring_oshmemfh.f90 -o ring_oshmemfh [login@cn204.anselm ]$ find . -executable -type f ./hello_oshmem ./dtrace/myppriv.sh ./dtrace/partrace.sh ./oshmem_shmalloc ./ring_cxx ./ring_usempi ./hello_mpifh ./hello_cxx ./oshmem_max_reduction ./oshmem_symmetric_data ./oshmem_strided_puts ./hello_usempif08 ./ring_usempif08 ./spc_example ./hello_oshmemfh ./ring_oshmem ./oshmem_circular_shift ./hello_c ./ring_c ./hello_usempi ./ring_oshmemfh ./connectivity_c ./ring_mpifh

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