From 10745936648b3e16244dc076e981a6509590ad16 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joachim=20Sch=C3=B6berl?= <joachim.schoeberl@tuwien.ac.at>
Date: Mon, 11 Feb 2019 20:01:07 +0100
Subject: [PATCH] mpi_wrapper in core

---
 libsrc/core/CMakeLists.txt  |   2 +-
 libsrc/core/mpi_wrapper.hpp | 108 ++++++++++++++++++++++++++++++++++++
 libsrc/core/ngcore.hpp      |   1 +
 3 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 libsrc/core/mpi_wrapper.hpp

diff --git a/libsrc/core/CMakeLists.txt b/libsrc/core/CMakeLists.txt
index 46a2230b..4f7dfdc7 100644
--- a/libsrc/core/CMakeLists.txt
+++ b/libsrc/core/CMakeLists.txt
@@ -33,7 +33,7 @@ if(USE_PYTHON)
 endif(USE_PYTHON)
 
 install(FILES ngcore.hpp archive.hpp type_traits.hpp version.hpp ngcore_api.hpp logging.hpp
-  exception.hpp symboltable.hpp paje_trace.hpp utils.hpp profiler.hpp
+  exception.hpp symboltable.hpp paje_trace.hpp utils.hpp profiler.hpp mpi_wrapper.hpp
   DESTINATION ${NG_INSTALL_DIR_INCLUDE}/core COMPONENT netgen_devel)
 
 if(ENABLE_CPP_CORE_GUIDELINES_CHECK)
diff --git a/libsrc/core/mpi_wrapper.hpp b/libsrc/core/mpi_wrapper.hpp
new file mode 100644
index 00000000..40b60b5c
--- /dev/null
+++ b/libsrc/core/mpi_wrapper.hpp
@@ -0,0 +1,108 @@
+#ifndef NGCORE_MPIWRAPPER_HPP
+#define NGCORE_MPIWRAPPER_HPP
+
+#ifdef PARALLEL
+#define OMPI_SKIP_MPICXX
+#include <mpi.h>
+#endif
+
+
+namespace ngcore
+{
+
+#ifdef PARALLEL
+
+  template <class T> struct MPI_typetrait  { };
+  
+  template <> struct MPI_typetrait<int> {
+    static MPI_Datatype MPIType () { return MPI_INT; } };
+
+  template <> struct MPI_typetrait<short> {
+    static MPI_Datatype MPIType () { return MPI_SHORT; } };
+
+  template <> struct MPI_typetrait<char> {
+    static MPI_Datatype MPIType () { return MPI_CHAR; } };  
+
+  template <> struct MPI_typetrait<size_t> {
+    static MPI_Datatype MPIType () { return MPI_UNIT64_T; } };
+
+  template <> struct MPI_typetrait<double> {
+    static MPI_Datatype MPIType () { return MPI_DOUBLE; } };
+
+  template <> struct MPI_typetrait<bool> {
+    static MPI_Datatype MPIType () { return MPI_C_BOOL; } };
+
+  
+  template <class T, class T2 = decltype(MPI_typetrait<T>::MPIType())>
+  inline MPI_Datatype GetMPIType () {
+    return MPI_typetrait<T>::MPIType();
+  }
+
+
+  class NgMPI_Comm
+  {
+    MPI_Comm comm;
+    int * refcount;
+  public:
+    NgMPI_Comm (MPI_Comm _comm, bool owns = false)
+      : comm(_comm)
+    {
+      if (!owns)
+        refcount = nullptr;
+      else
+        refcount = new int{1};
+    }
+    
+    NgMPI_Comm (const NgMPI_Comm & c)
+      : comm(c.comm), refcount(c.refcount)
+    {
+      if (refcount) (*refcount)++;
+    }
+
+    NgMPI_Comm (NgMPI_Comm && c)
+      : comm(c.comm), refcount(c.refcount)
+    {
+      c.refcount = nullptr;
+    }
+    
+    ~NgMPI_Comm()
+    {
+      if (refcount)
+        if (--(*refcount) == 0)
+          MPI_Comm_free(&comm);
+    }
+    
+    operator MPI_Comm() const { return comm; }
+
+    auto Rank() const { int r; MPI_Comm_rank(comm, &r); return r; }
+    auto Size() const { int s; MPI_Comm_size(comm, &s); return s; }    
+  };
+
+  
+#else
+  
+  class NgMPI_Comm
+  {
+    
+  public:
+    NgMPI_Comm (int _comm, bool owns = false)
+    { ; }
+
+    size_t Rank() const { return 0; }
+    size_t Size() const { return 1; }
+  };  
+  
+#endif
+
+
+
+
+
+
+  
+
+  
+}
+
+#endif
+
diff --git a/libsrc/core/ngcore.hpp b/libsrc/core/ngcore.hpp
index d73a3ed9..8cc937c0 100644
--- a/libsrc/core/ngcore.hpp
+++ b/libsrc/core/ngcore.hpp
@@ -7,5 +7,6 @@
 #include "profiler.hpp"
 #include "symboltable.hpp"
 #include "version.hpp"
+#include "mpi_wrapper.hpp"
 
 #endif // NETGEN_CORE_NGCORE_HPP