Switched used MPI bindings to C style (C++ is deprecated and caused problems on one machine)

Author: Ithanil

src/MPIMCI.hpp

@@ -1,28 +1,35 @@
 #ifndef MPIMCI
 #define MPIMCI
 
-
+#include <stdexcept>
 #include <mpi.h>
 #include "MCIntegrator.hpp"
 
 namespace MPIMCI
 {
     int init() // return mpi rank of process
     {
-        if (MPI::Is_initialized()) throw std::runtime_error("MPI already initialized!");
-        MPI::Init();
-        MPI::COMM_WORLD.Set_errhandler(MPI::ERRORS_THROW_EXCEPTIONS);
-        return MPI::COMM_WORLD.Get_rank();
+        int isinit;
+        MPI_Initialized(&isinit);
+        if (isinit==1) throw std::runtime_error("MPI already initialized!");
+        MPI_Init(NULL, NULL);
+        int myrank;
+        MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
+        return myrank;
     }
 
     void integrate(MCI * const mci, const long &Nmc, double * average, double * error, bool findMRT2step=true, bool initialdecorrelation=true, bool use_mpi=true) // by setting use_mpi to false you can use this without requiring MPI
     {
         if (use_mpi) {
             // make sure the user has MPI in the correct state
-            if (!MPI::Is_initialized()) throw std::runtime_error("MPI not initialized!");
-            if (MPI::Is_finalized()) throw std::runtime_error("MPI already finalized!");
+            int isinit, isfinal;
+            MPI_Initialized(&isinit);
+            if (isinit==0) throw std::runtime_error("MPI not initialized!");
+            MPI_Finalized(&isfinal);
+            if (isfinal==1) throw std::runtime_error("MPI already finalized!");
 
-            const int nranks = MPI::COMM_WORLD.Get_size();
+            int nranks;
+            MPI_Comm_size(MPI_COMM_WORLD, &nranks);
 
             // the results are stored in myAverage/Error and then reduced into the same average/error for all processes
             double myAverage[mci->getNObsDim()];
@@ -31,10 +38,10 @@ namespace MPIMCI
             mci->integrate(Nmc, myAverage, myError, findMRT2step, initialdecorrelation);
 
             for (int i=0; i<mci->getNObsDim(); ++i) {
-                MPI::COMM_WORLD.Allreduce(&myAverage[i], &average[i], 1, MPI::DOUBLE, MPI::SUM);
+                MPI_Allreduce(&myAverage[i], &average[i], 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
 
                 myError[i] *= myError[i];
-                MPI::COMM_WORLD.Allreduce(&myError[i], &error[i], 1, MPI::DOUBLE, MPI::SUM);
+                MPI_Allreduce(&myError[i], &error[i], 1, MPI_DOUBLE, MPI_SUM, MPI_COMM_WORLD);
 
                 average[i] /= nranks;
                 error[i] = sqrt(error[i]) / nranks;
@@ -48,10 +55,13 @@ namespace MPIMCI
     void finalize()
     {
         // make sure the user has MPI in the correct state
-        if (!MPI::Is_initialized()) throw std::runtime_error("MPI not initialized!");
-        if (MPI::Is_finalized()) throw std::runtime_error("MPI already finalized!");
+        int isinit, isfinal;
+        MPI_Initialized(&isinit);
+        if (isinit==0) throw std::runtime_error("MPI not initialized!");
+        MPI_Finalized(&isfinal);
+        if (isfinal==1) throw std::runtime_error("MPI already finalized!");
 
-        MPI::Finalize();
+        MPI_Finalize();
     }
 };