From c2aab68b3f3c85b2d3b18a0990a615330500aa65 Mon Sep 17 00:00:00 2001
From: John Abraham <john.abraham@gatech.edu>
Date: Fri, 13 May 2011 16:31:25 -0700
Subject: [PATCH] Bug 1087 Call MPI_Finalize to exit MPI environment

---
 src/mpi/examples/nms-p2p-nix-distributed.cc |  3 ++-
 src/mpi/examples/simple-distributed.cc      |  2 ++
 src/mpi/examples/third-distributed.cc       |  2 ++
 src/mpi/model/mpi-interface.cc              | 22 +++++++++++++++++++++
 src/mpi/model/mpi-interface.h               |  7 ++++++-
 5 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/mpi/examples/nms-p2p-nix-distributed.cc b/src/mpi/examples/nms-p2p-nix-distributed.cc
index f0f71e07a..381dd0f45 100644
--- a/src/mpi/examples/nms-p2p-nix-distributed.cc
+++ b/src/mpi/examples/nms-p2p-nix-distributed.cc
@@ -601,7 +601,8 @@ main (int argc, char *argv[])
   TIMER_NOW (t2);
   cout << "Simulator finished." << endl;
   Simulator::Destroy ();
-
+  // Exit the MPI execution environment
+  MpiInterface::Disable ();
   double d1 = TIMER_DIFF (t1, t0), d2 = TIMER_DIFF (t2, t1);
   cout << "-----" << endl << "Runtime Stats:" << endl;
   cout << "Simulator init time: " << d1 << endl;
diff --git a/src/mpi/examples/simple-distributed.cc b/src/mpi/examples/simple-distributed.cc
index 9fd237165..c16fbea1b 100644
--- a/src/mpi/examples/simple-distributed.cc
+++ b/src/mpi/examples/simple-distributed.cc
@@ -245,6 +245,8 @@ main (int argc, char *argv[])
   Simulator::Stop (Seconds (5));
   Simulator::Run ();
   Simulator::Destroy ();
+  // Exit the MPI execution environment
+  MpiInterface::Disable ();
   return 0;
 #else
   NS_FATAL_ERROR ("Can't use distributed simulator without MPI compiled in");
diff --git a/src/mpi/examples/third-distributed.cc b/src/mpi/examples/third-distributed.cc
index 31c581584..681c08bc3 100644
--- a/src/mpi/examples/third-distributed.cc
+++ b/src/mpi/examples/third-distributed.cc
@@ -239,6 +239,8 @@ main (int argc, char *argv[])
 
   Simulator::Run ();
   Simulator::Destroy ();
+  // Exit the MPI execution environment
+  MpiInterface::Disable ();
   return 0;
 
 #else
diff --git a/src/mpi/model/mpi-interface.cc b/src/mpi/model/mpi-interface.cc
index 0b8fba514..4199bc36d 100644
--- a/src/mpi/model/mpi-interface.cc
+++ b/src/mpi/model/mpi-interface.cc
@@ -284,4 +284,26 @@ MpiInterface::TestSendComplete ()
 #endif
 }
 
+void 
+MpiInterface::Disable ()
+{
+#ifdef NS3_MPI
+  int flag = 0 ;
+  MPI_Initialized (&flag);
+  if (flag)
+    {
+      MPI_Finalize ();
+      m_enabled = false;
+      m_initialized = false;
+    }
+  else
+    {
+      NS_FATAL_ERROR ("Cannot disable MPI environment without Initializing it first");
+    }
+#else
+  NS_FATAL_ERROR ("Can't use distributed simulator without MPI compiled in");
+#endif
+}
+
+
 } // namespace ns3
diff --git a/src/mpi/model/mpi-interface.h b/src/mpi/model/mpi-interface.h
index c29126758..a361dfbea 100644
--- a/src/mpi/model/mpi-interface.h
+++ b/src/mpi/model/mpi-interface.h
@@ -97,7 +97,12 @@ public:
    * Sets up MPI interface
    */
   static void Enable (int* pargc, char*** pargv);
-
+  /**
+   * Terminates the MPI environment by calling MPI_Finalize
+   * This function must be called after Destroy ()
+   * It also resets m_initialized, m_enabled
+   */
+  static void Disable ();
   /**
    * \param p packet to send
    * \param rxTime received time at destination node