1 files changed, 129 insertions, 0 deletions
diff --git a/src/boost/libs/mpi/example/generate_collect.cpp b/src/boost/libs/mpi/example/generate_collect.cpp
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+++ b/src/boost/libs/mpi/example/generate_collect.cpp
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+// Copyright (C) 2006 Douglas Gregor <doug.gregor@gmail.com>
+
+// Use, modification and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// An example using Boost.MPI's split() operation on communicators to
+// create separate data-generating processes and data-collecting
+// processes.
+#include <boost/mpi.hpp>
+#include <iostream>
+#include <cstdlib>
+#include <boost/serialization/vector.hpp>
+namespace mpi = boost::mpi;
+
+enum message_tags { msg_data_packet, msg_broadcast_data, msg_finished };
+
+void generate_data(mpi::communicator local, mpi::communicator world)
+{
+  using std::srand;
+  using std::rand;
+
+  // The rank of the collector within the world communicator
+  int master_collector = local.size();
+
+  srand(time(0) + world.rank());
+
+  // Send out several blocks of random data to the collectors.
+  int num_data_blocks = rand() % 3 + 1;
+  for (int block = 0; block < num_data_blocks; ++block) {
+    // Generate some random data
+    int num_samples = rand() % 1000;
+    std::vector<int> data;
+    for (int i = 0; i < num_samples; ++i) {
+      data.push_back(rand());
+    }
+
+    // Send our data to the master collector process.
+    std::cout << "Generator #" << local.rank() << " sends some data..."
+              << std::endl;
+    world.send(master_collector, msg_data_packet, data);
+  }
+
+  // Wait for all of the generators to complete
+  (local.barrier)();
+
+  // The first generator will send the message to the master collector
+  // indicating that we're done.
+  if (local.rank() == 0)
+    world.send(master_collector, msg_finished);
+}
+
+void collect_data(mpi::communicator local, mpi::communicator world)
+{
+  // The rank of the collector within the world communicator
+  int master_collector = world.size() - local.size();
+
+  if (world.rank() == master_collector) {
+    while (true) {
+      // Wait for a message
+      mpi::status msg = world.probe();
+      if (msg.tag() == msg_data_packet) {
+        // Receive the packet of data
+        std::vector<int> data;
+        world.recv(msg.source(), msg.tag(), data);
+
+        // Tell each of the collectors that we'll be broadcasting some data
+        for (int dest = 1; dest < local.size(); ++dest)
+          local.send(dest, msg_broadcast_data, msg.source());
+
+        // Broadcast the actual data.
+        broadcast(local, data, 0);
+      } else if (msg.tag() == msg_finished) {
+        // Receive the message
+        world.recv(msg.source(), msg.tag());
+
+        // Tell each of the collectors that we're finished
+        for (int dest = 1; dest < local.size(); ++dest)
+          local.send(dest, msg_finished);
+
+        break;
+      }
+    }
+  } else {
+    while (true) {
+      // Wait for a message from the master collector
+      mpi::status msg = local.probe();
+      if (msg.tag() == msg_broadcast_data) {
+        // Receive the broadcast message
+        int originator;
+        local.recv(msg.source(), msg.tag(), originator);
+
+        // Receive the data broadcasted from the master collector
+        std::vector<int> data;
+        broadcast(local, data, 0);
+
+        std::cout << "Collector #" << local.rank()
+                  << " is processing data from generator #" << originator
+                  << "." << std::endl;
+      } else if (msg.tag() == msg_finished) {
+        // Receive the message
+        local.recv(msg.source(), msg.tag());
+
+        break;
+      }
+    }
+  }
+}
+
+int main(int argc, char* argv[])
+{
+  mpi::environment env(argc, argv);
+  mpi::communicator world;
+
+  if (world.size() < 3) {
+    if (world.rank() == 0) {
+      std::cerr << "Error: this example requires at least 3 processes."
+                << std::endl;
+    }
+    env.abort(-1);
+  }
+
+  bool is_generator = world.rank() < 2 * world.size() / 3;
+  mpi::communicator local = world.split(is_generator? 0 : 1);
+  if (is_generator) generate_data(local, world);
+  else collect_data(local, world);
+
+  return 0;
+}