Something I've been working on with low bandwidth over the past

several weeks: marshaling hello world and ring examples in all 4
languages (C, C++, F77, F90), making them consistent and pretty, and
adding them to the build system in a non-intrusive way.

This commit was SVN r10792.

Makefile.am

@@ -9,6 +9,7 @@
 #                         University of Stuttgart.  All rights reserved.
 # Copyright (c) 2004-2005 The Regents of the University of California.
 #                         All rights reserved.
+# Copyright (c) 2006      Cisco Systems, Inc.  All rights reserved.
 # $COPYRIGHT$
 # 
 # Additional copyrights may follow
@@ -19,5 +20,7 @@
 SUBDIRS = config contrib $(MCA_PROJECT_SUBDIRS) test
 EXTRA_DIST = README INSTALL VERSION Doxyfile LICENSE
 
+include examples/Makefile.include
+
 dist-hook:
 	csh "$(top_srcdir)/config/distscript.csh" "$(top_srcdir)" "$(distdir)" "$(OMPI_VERSION)" "$(OMPI_SVN_R)"

examples/Makefile

@@ -0,0 +1,70 @@
+#
+# Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
+#                         University Research and Technology
+#                         Corporation.  All rights reserved.
+# Copyright (c) 2004-2005 The University of Tennessee and The University
+#                         of Tennessee Research Foundation.  All rights
+#                         reserved.
+# Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
+#                         University of Stuttgart.  All rights reserved.
+# Copyright (c) 2004-2005 The Regents of the University of California.
+#                         All rights reserved.
+# $COPYRIGHT$
+# 
+# Additional copyrights may follow
+# 
+# $HEADER$
+#
+
+# Use the Open MPI-provided wrapper compilers
+
+CC = mpicc
+CXX = mpic++
+F77 = mpif77
+FC = mpif90
+
+# Using -g is not necessary, but it is helpful for example programs,
+# especially if users want to examine them with debuggers.
+
+CFLAGS = -g
+CXXFLAGS = -g
+F77FLAGS = -g
+FCFLAGS = -g
+
+# Example programs to build
+
+EXAMPLES = hello_c hello_cxx hello_f77 hello_f90 \
+           ring_c ring_cxx ring_f77 ring_f90
+
+# Default target.  Always build the C example.  Only build the others
+# if Open MPI was build with the relevant language bindings.
+
+all: hello_c ring_c
+	@ if test "`ompi_info --parsable | grep bindings:cxx:yes`" != ""; then \
+	    $(MAKE) hello_cxx ring_cxx; \
+	fi
+	@ if test "`ompi_info --parsable | grep bindings:f77:yes`" != ""; then \
+	    $(MAKE) hello_f77 ring_f77; \
+	fi
+	@ if test "`ompi_info --parsable | grep bindings:f90:yes`" != ""; then \
+	    $(MAKE) hello_f90 ring_f90; \
+	fi
+
+
+# The usual "clean" target
+
+clean:
+	rm -f $(EXAMPLES) *~ *.o
+
+# Don't rely on default rules for the fortran examples
+
+hello_f77: hello_f77.f
+	$(F77) $(F77FLAGS) $< -o $@
+ring_f77: ring_f77.f
+	$(F77) $(F77FLAGS) $< -o $@
+
+hello_f90: hello_f90.f90
+	$(FC) $(FCFLAGS) $< -o $@
+ring_f90: ring_f90.f90
+	$(FC) $(FCFLAGS) $< -o $@
+

examples/Makefile.include

@@ -0,0 +1,40 @@
+# -*- makefile -*-
+#
+# Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
+#                         University Research and Technology
+#                         Corporation.  All rights reserved.
+# Copyright (c) 2004-2005 The University of Tennessee and The University
+#                         of Tennessee Research Foundation.  All rights
+#                         reserved.
+# Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
+#                         University of Stuttgart.  All rights reserved.
+# Copyright (c) 2004-2005 The Regents of the University of California.
+#                         All rights reserved.
+# Copyright (c) 2006      Cisco Systems, Inc.  All rights reserved.
+# $COPYRIGHT$
+# 
+# Additional copyrights may follow
+# 
+# $HEADER$
+#
+
+# Note that this file does not stand on its own.  It is included by a
+# higher-level Makefile so that Automake features such as "make dist"
+# work properly (and include all the relevant files in this directory
+# in the distribution tarball).
+
+# If you are looking for the file that builds these examples, look at
+# "Makefile" in this same directory (it is *NOT* generated by
+# Automake).
+
+EXTRA_DIST += \
+        examples/README \
+        examples/Makefile \
+        examples/hello_c.c \
+        examples/hello_cxx.cc \
+        examples/hello_f77.f \
+        examples/hello_f90.f90 \
+        examples/ring_c.c \
+        examples/ring_cxx.cc \
+        examples/ring_f77.f \
+        examples/ring_f90.f90

examples/README

@@ -0,0 +1,42 @@
+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.
+
+The files in this directory are sample MPI applications provided both
+as a trivial primer to MPI as well as simple tests to ensure that your
+Open MPI installation is working properly.
+
+If you are looking for a comprehensive MPI tutorial, these samples are
+not enough.  An excellent MPI tutorial is available here:
+
+        http://webct.ncsa.uiuc.edu:8900/public/MPI/
+
+There are 2 MPI examples in this directory, each in four languages:
+
+- Hello world
+  C:   hello_c.c
+  C++: hello_cxx.cc
+  F77: hello_f77.f
+  F90: hello_f90.f90
+
+- Send a trivial message around in a ring
+  C:   ring_c.c
+  C++: ring_cxx.cc
+  F77: ring_f77.f
+  F90: ring_f90.f90
+
+The Makefile in this directory will build as many of the examples as
+you have language support (e.g., if you do not have F90 bindings
+compiled as part of Open MPI, the F90 examples will be skipped).
+
+The Makefile assumes that the wrapper compilers mpicc, mpic++, mpif77,
+and mpif90 are in your path.
+
+Although the Makefile is tailored for Open MPI (e.g., it checks the
+"ompi_info" command to see if you have support for C++, F77, and F90),
+all of the example programs are pure MPI, and therefore not specific
+to Open MPI.  Hence, you can use a different MPI implementation to
+complie and run these programs if you wish.
+
+Make today an Open MPI day!

examples/hello_c.c

@@ -0,0 +1,24 @@
+/*
+ * 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 <stdio.h>
+#include "mpi.h"
+
+int main(int argc, char* argv[])
+{
+    int rank, size;
+
+    MPI_Init(NULL, NULL);
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+    printf("Hello, world, I am %d of %d\n", rank, size);
+    MPI_Finalize();
+
+    return 0;
+}

examples/hello_cxx.cc

@@ -0,0 +1,24 @@
+//
+// 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 <iostream>
+#include "mpi.h"
+
+int main(int argc, char **argv)
+{
+    int rank, size;
+
+    MPI::Init();
+    rank = MPI::COMM_WORLD.Get_rank();
+    size = MPI::COMM_WORLD.Get_size();
+    std::cout << "Hello, world!  I am " << rank << " of " << size << std::endl;
+    MPI::Finalize();
+
+    return 0;
+}

examples/hello_f77.f

@@ -0,0 +1,20 @@
+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      Cisco Systems, Inc.  All rights reserved.
+C
+C Sample MPI "hello world" application in Fortran 77
+C
+        program main
+        implicit none
+        include 'mpif.h'
+        integer ierr, rank, size
+
+        call MPI_INIT(ierr)
+        call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
+        call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr)
+        print *, "Hello, world, I am ", rank, " of ", size
+        call MPI_FINALIZE(ierr)
+
+        end

examples/hello_f90.f90

@@ -0,0 +1,21 @@
+!
+! 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      Cisco Systems, Inc.  All rights reserved.
+!
+! Sample MPI "hello world" application in Fortran 90
+!
+program main
+    use mpi
+    implicit none
+    integer :: ierr, rank, size
+
+    call MPI_INIT(ierr)
+    call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
+    call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr)
+    print *, "Hello, world, I am ", rank, " of ", size
+    call MPI_FINALIZE(ierr)
+end

examples/ring_c.c

@@ -0,0 +1,79 @@
+/*
+ * 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.
+ *
+ * Simple ring test program
+ */
+
+#include <stdio.h>
+#include "mpi.h"
+
+int main(int argc, char *argv[])
+{
+    int rank, size, next, prev, message, tag = 201;
+
+    /* Start up MPI */
+
+    MPI_Init(NULL, NULL);
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+ 
+    /* Calculate the rank of the next process in the ring.  Use the
+       modulus operator so that the last process "wraps around" to
+       rank zero. */
+
+    next = (rank + 1) % size;
+    prev = (rank + size - 1) % size;
+
+    /* If we are the "master" process (i.e., MPI_COMM_WORLD rank 0),
+       put the number of times to go around the ring in the
+       message. */
+
+    if (0 == rank) {
+        message = 10;
+
+        printf("Process 0 sending %d to %d, tag %d (%d processes in ring)\n", 
+               message, next, tag, size);
+        MPI_Send(&message, 1, MPI_INT, next, tag, MPI_COMM_WORLD); 
+        printf("Process 0 sent to %d\n", next);
+    }
+
+    /* Pass the message around the ring.  The exit mechanism works as
+       follows: the message (a positive integer) is passed around the
+       ring.  Each time it passes rank 0, it is decremented.  When
+       each processes receives a message containing a 0 value, it
+       passes the message on to the next process and then quits.  By
+       passing the 0 message first, every process gets the 0 message
+       and can quit normally. */
+
+    while (1) {
+        MPI_Recv(&message, 1, MPI_INT, prev, tag, MPI_COMM_WORLD, 
+                 MPI_STATUS_IGNORE);
+
+        if (0 == rank) {
+            --message;
+            printf("Process 0 decremented value: %d\n", message);
+        }
+
+        MPI_Send(&message, 1, MPI_INT, next, tag, MPI_COMM_WORLD);
+        if (0 == message) {
+            printf("Process %d exiting\n", rank);
+            break;
+        }
+    }
+
+    /* The last process does one extra send to process 0, which needs
+       to be received before the program can exit */
+
+    if (0 == rank) {
+        MPI_Recv(&message, 1, MPI_INT, prev, tag, MPI_COMM_WORLD,
+                 MPI_STATUS_IGNORE);
+    }
+    
+    /* All done */
+
+    MPI_Finalize();
+    return 0;
+}

examples/ring_cxx.cc

@@ -0,0 +1,78 @@
+//
+// 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.
+//
+// Simple ring test program
+//
+
+#include <iostream>
+#include "mpi.h"
+
+int main(int argc, char *argv[])
+{
+    int rank, size, next, prev, message, tag = 201;
+
+    // Start up MPI
+
+    MPI::Init();
+    rank = MPI::COMM_WORLD.Get_rank();
+    size = MPI::COMM_WORLD.Get_size();
+ 
+    // Calculate the rank of the next process in the ring.  Use the
+    // modulus operator so that the last process "wraps around" to
+    // rank zero.
+
+    next = (rank + 1) % size;
+    prev = (rank + size - 1) % size;
+
+    // If we are the "master" process (i.e., MPI_COMM_WORLD rank 0),
+    // put the number of times to go around the ring in the message.
+
+    if (0 == rank) {
+        message = 10;
+
+        std::cout << "Process 0 sending " << message << " to " << next
+                  << ", tag " << tag << " (" << size << " processes in ring)"
+                  << std::endl;
+        MPI::COMM_WORLD.Send(&message, 1, MPI::INT, next, tag);
+        std::cout << "Process 0 sent to " << next << std::endl;
+    }
+
+    // Pass the message around the ring.  The exit mechanism works as
+    // follows: the message (a positive integer) is passed around the
+    // ring.  Each time it passes rank 0, it is decremented.  When
+    // each processes receives a message containing a 0 value, it
+    // passes the message on to the next process and then quits.  By
+    // passing the 0 message first, every process gets the 0 message
+    // and can quit normally.
+
+    while (1) {
+        MPI::COMM_WORLD.Recv(&message, 1, MPI::INT, prev, tag);
+
+        if (0 == rank) {
+            --message;
+            std::cout << "Process 0 decremented value: " << message 
+                      << std::endl;
+        }
+
+        MPI::COMM_WORLD.Send(&message, 1, MPI::INT, next, tag);
+        if (0 == message) {
+            std::cout << "Process " << rank << " exiting" << std::endl;
+            break;
+        }
+    }
+
+    // The last process does one extra send to process 0, which needs
+    // to be received before the program can exit */
+
+    if (0 == rank) {
+        MPI::COMM_WORLD.Recv(&message, 1, MPI::INT, prev, tag);
+    }
+    
+    // All done
+
+    MPI::Finalize();
+    return 0;
+}

examples/ring_f77.f

@@ -0,0 +1,76 @@
+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      Cisco Systems, Inc.  All rights reserved.
+C
+C Simple ring test program
+C
+      program ring_f77
+      implicit none
+      include 'mpif.h'
+      integer rank, size, tag, next, from, message, ierr
+
+C     Start up MPI */
+
+      call MPI_INIT(ierr)
+      call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
+      call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr)
+
+C     Calculate the rank of the next process in the ring.  Use the
+C     modulus operator so that the last process "wraps around" to rank
+C     zero.
+
+      tag = 201
+      next = mod((rank + 1), size)
+      from = mod((rank + size - 1), size)
+      
+C     If we are the "master" process (i.e., MPI_COMM_WORLD rank 0), put
+C     the number of times to go around the ring in the message.
+
+      if (rank .eq. 0) then
+         message = 10
+
+         print *, 'Process 0 sending ', message, ' to ', next
+         call MPI_SEND(message, 1, MPI_INTEGER, next, tag, 
+     &        MPI_COMM_WORLD, ierr)
+      endif
+
+C     Pass the message around the ring.  The exit mechanism works as
+C     follows: the message (a positive integer) is passed around the
+C     ring.  Each time it passes rank 0, it is decremented.  When each
+C     processes receives a message containing a 0 value, it passes the
+C     message on to the next process and then quits.  By passing the 0
+C     message first, every process gets the 0 message and can quit
+C     normally.
+
+ 10   call MPI_RECV(message, 1, MPI_INTEGER, from, tag, 
+     &     MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
+
+      if (rank .eq. 0) then
+         message = message - 1
+         print *, 'Process 0 decremented value:', message
+      endif
+
+      call MPI_SEND(message, 1, MPI_INTEGER, next, tag, 
+     &     MPI_COMM_WORLD, ierr)
+      
+      if (message .eq. 0) then
+         print *, 'Process ', rank, ' exiting'
+         goto 20
+      endif
+      goto 10
+
+C     The last process does one extra send to process 0, which needs to
+C     be received before the program can exit
+
+ 20   if (rank .eq. 0) then
+         call MPI_RECV(message, 1, MPI_INTEGER, from, tag, 
+     &        MPI_COMM_WORLD, MPI_STATUS_IGNORE, ierr)
+      endif
+
+C     All done
+
+      call MPI_FINALIZE(ierr)
+      end
+      

examples/ring_f90.f90

@@ -0,0 +1,53 @@
+!
+! 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.
+!
+! Simple ring test program
+!
+program ring
+  use mpi
+  implicit none
+  integer :: rank, size, tag, next, from, message, ierr
+
+  call MPI_INIT(ierr)
+  call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
+  call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierr)
+
+  tag = 201
+  next = mod((rank + 1), size)
+  from = mod((rank + size - 1), size)
+      
+  if (rank .eq. 0) then
+     message = 10
+
+     print *, 'Process 0 sending ', message, ' to ',  next
+     call MPI_SEND(message, 1, MPI_INTEGER, next, tag, MPI_COMM_WORLD, ierr)
+  endif
+
+
+10 call MPI_RECV(message, 1, MPI_INTEGER, from, tag, MPI_COMM_WORLD, &
+        MPI_STATUS_IGNORE, ierr)
+
+  if (rank .eq. 0) then
+     message = message - 1
+     print *, 'Process 0 decremented num'
+  endif
+
+  call MPI_SEND(message, 1, MPI_INTEGER, next, tag, MPI_COMM_WORLD, ierr)
+      
+  if (message .eq. 0) then
+     print *, 'Process ', rank, ' exiting'
+     goto 20
+  endif
+  goto 10
+
+ 20 if (rank .eq. 0) then
+     call MPI_RECV(message, 1, MPI_INTEGER, from, tag, MPI_COMM_WORLD, &
+          MPI_STATUS_IGNORE, ierr)
+  endif
+
+  call MPI_FINALIZE(ierr)
+end program
+