More stable MPI; resolve potential issue with global MPIController

life-time

Author: mlund

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.11.4 FATAL_ERROR)
 
-project(neofaunus)
+project(faunus)
 
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED YES)
@@ -185,19 +185,19 @@ include_directories(SYSTEM ${eigen_SOURCE_DIR} ${doctest_SOURCE_DIR} ${modernjso
 
 # faunus cpp files
 set(objs
+    ${CMAKE_SOURCE_DIR}/src/random.cpp
+    ${CMAKE_SOURCE_DIR}/src/mpi.cpp
+    ${CMAKE_SOURCE_DIR}/src/core.cpp
+    ${CMAKE_SOURCE_DIR}/src/units.cpp
     ${CMAKE_SOURCE_DIR}/src/analysis.cpp
     ${CMAKE_SOURCE_DIR}/src/atomdata.cpp
-    ${CMAKE_SOURCE_DIR}/src/core.cpp
     ${CMAKE_SOURCE_DIR}/src/energy.cpp
     ${CMAKE_SOURCE_DIR}/src/geometry.cpp
     ${CMAKE_SOURCE_DIR}/src/io.cpp
     ${CMAKE_SOURCE_DIR}/src/move.cpp
-    ${CMAKE_SOURCE_DIR}/src/mpi.cpp
     ${CMAKE_SOURCE_DIR}/src/particle.cpp
     ${CMAKE_SOURCE_DIR}/src/penalty.cpp
-    ${CMAKE_SOURCE_DIR}/src/potentials.cpp
-    ${CMAKE_SOURCE_DIR}/src/random.cpp
-    ${CMAKE_SOURCE_DIR}/src/units.cpp)
+    ${CMAKE_SOURCE_DIR}/src/potentials.cpp)
 
 set_source_files_properties(${objs} PROPERTIES LANGUAGE CXX)
 
@@ -247,7 +247,7 @@ target_compile_definitions(faunus PRIVATE
     FAUNUS_TIPSFILE=\"${CMAKE_INSTALL_PREFIX}/share/faunus/tips.json\",\"${CMAKE_SOURCE_DIR}/tips.json\" )
 
 if (MPI_CXX_FOUND)
-    target_link_libraries(faunus PRIVATE MPI::MPI_C)
+    target_link_libraries(faunus PRIVATE MPI::MPI_CXX)
     target_compile_definitions(faunus PRIVATE ENABLE_MPI)
 endif()
 

src/faunus.cpp

@@ -1,7 +1,7 @@
 #include "core.h"
+#include "mpi.h"
 #include "move.h"
 #include "analysis.h"
-#include "mpi.h"
 #include "multipole.h"
 #include "docopt.h"
 #include <cstdlib>
@@ -62,6 +62,8 @@ int main( int argc, char **argv )
         auto args = docopt::docopt( USAGE,
                 { argv + 1, argv + argc }, true, version);
 
+        mpi.init(); // initialize MPI, if available
+
         // --notips
         if (not args["--notips"].asBool())
             usageTip.load( {FAUNUS_TIPSFILE} ); 
@@ -164,6 +166,8 @@ int main( int argc, char **argv )
             f << std::setw(4) << j << endl;
         }
 
+        mpi.finalize();
+
     } catch (std::exception &e) {
         std::cerr << e.what() << endl;
         return EXIT_FAILURE;

src/mpi.cpp

@@ -11,8 +11,21 @@ namespace Faunus {
          * data (parallel tempering, for example). The prefix format is
          * \li \c "prefix + mpi%r." where \c \%r is the rank number.
          */
-        //inline MPIController::MPIController(MPI_Comm c) : comm(MPI_COMM_WORLD), _master(0) {
-        MPIController::MPIController() {
+        MPIController::~MPIController() {
+            finalize();
+        }
+
+        void MPIController::finalize() {
+            if (mpi_initialized) {
+#ifdef ENABLE_MPI
+                MPI_Finalize();
+#endif
+                mpi_initialized=false;
+            }
+        }
+
+        void MPIController::init() {
+            mpi_initialized=true;
 #ifdef ENABLE_MPI
             MPI_Init(NULL,NULL);
             MPI_Comm_size(comm, &_nproc);
@@ -25,14 +38,8 @@ namespace Faunus {
             }
         }
 
-        MPIController::~MPIController() {
-            f.close();
-#ifdef ENABLE_MPI
-            MPI_Finalize();
-#endif
-        }
-
         std::ostream& MPIController::cout() {
+            assert(mpi_initialized);
 #ifdef ENABLE_MPI
             if (_nproc>1)
                 return f;

src/mpi.h

@@ -36,7 +36,8 @@ namespace Faunus {
          *
          * This is the MPI controller required for all MPI programs.
          *
-         *     MPIController mpi; // call this very first thing in your program
+         *     MPIController mpi;
+         *     mpi.init();
          *     std::cout << "I'm rank " << mpi.rank << " out of " << mpi.nproc;
          *     mpi.cout << "This will go to a file called mpi%r.stdout where %r is my rank"
          *     if (mpi.isMaster())
@@ -51,7 +52,8 @@ namespace Faunus {
          */
         class MPIController {
             public:
-                MPIController();        //!< Constructor
+                void init();            //!< Initialize MPI and file IO
+                void finalize();        //!< Finalize MPI
                 ~MPIController();       //!< End of all MPI calls!
                 int nproc() const;      //!< Number of processors in communicator
                 int rank() const;       //!< Rank of process
@@ -68,6 +70,7 @@ namespace Faunus {
                 int _nproc=1;      //!< Number of processors in communicator
                 int _rank=0;       //!< Rank of process
                 int _master=0;     //!< Rank number of the master
+                bool mpi_initialized=false;
         };
 
         void to_json(json&, const MPIController&);