Enable dummy mpi functions in mpi_wrapper.hpp again, skip new runtime-wrapper code if USE_MPI=OFF

libsrc/core/mpi_wrapper.hpp

@@ -15,6 +15,8 @@
 namespace ngcore
 {
 
+#ifdef PARALLEL
+
   template <class T> struct MPI_typetrait  { };
   
   template <> struct MPI_typetrait<int> {
@@ -462,6 +464,117 @@ namespace ngcore
     }
   };
   
+
+
+  
+
+#else // PARALLEL
+  class NG_MPI_Comm {
+    int nr;
+  public:
+    NG_MPI_Comm (int _nr = 0) : nr(_nr) { ; }
+    operator int() const { return nr; }
+    bool operator== (NG_MPI_Comm c2) const { return nr == c2.nr; }
+  };
+  static NG_MPI_Comm NG_MPI_COMM_WORLD = 12345, NG_MPI_COMM_NULL = 10000;
+
+  typedef int NG_MPI_Op;
+  typedef int NG_MPI_Datatype;  
+  typedef int NG_MPI_Request;
+  
+  enum { NG_MPI_SUM = 0, NG_MPI_MIN = 1, NG_MPI_MAX = 2, NG_MPI_LOR = 4711 };
+
+  inline void NG_MPI_Type_contiguous ( int, NG_MPI_Datatype, NG_MPI_Datatype*) { ; } 
+  inline void NG_MPI_Type_commit ( NG_MPI_Datatype * ) { ; }
+
+  template <class T> struct MPI_typetrait  {
+    static NG_MPI_Datatype MPIType () { return -1; }    
+  };
+  template <class T, class T2=void>
+  inline NG_MPI_Datatype GetMPIType () { return -1; }
+  
+  class NgMPI_Comm
+  {
+    
+  public:
+    NgMPI_Comm () { ; } 
+    NgMPI_Comm (NG_MPI_Comm _comm, bool owns = false) { ; }
+
+    size_t Rank() const { return 0; }
+    size_t Size() const { return 1; }
+    bool ValidCommunicator() const { return false; }
+    void Barrier() const { ; } 
+    operator NG_MPI_Comm() const { return NG_MPI_Comm(); }
+
+    template<typename T>
+    void Send( T & val, int dest, int tag) const { ; }
+    
+    template<typename T>
+    void Send(FlatArray<T> s, int dest, int tag) const { ; }
+
+    template<typename T>
+    void Recv (T & val, int src, int tag) const { ; }
+
+    template <typename T>
+    void Recv (FlatArray <T> s, int src, int tag) const { ; }
+
+    template <typename T>
+    void Recv (Array <T> & s, int src, int tag) const { ; }
+
+    template<typename T>
+    NG_MPI_Request ISend (T & val, int dest, int tag) const { return 0; } 
+    
+    template<typename T>
+    NG_MPI_Request ISend (FlatArray<T> s, int dest, int tag) const { return 0; }
+
+    template<typename T>
+    NG_MPI_Request IRecv (T & val, int dest, int tag) const { return 0; } 
+    
+    template<typename T>
+    NG_MPI_Request IRecv (FlatArray<T> s, int src, int tag) const { return 0; }
+
+    template <typename T>
+    T Reduce (T d, const NG_MPI_Op & op, int root = 0) const { return d; }
+    
+    template <typename T>
+    T AllReduce (T d, const NG_MPI_Op & op) const { return d; }
+
+    template <typename T>
+    void AllReduce (FlatArray<T> d, const NG_MPI_Op & op) const { ; }
+    
+    template <typename T>
+    void Bcast (T & s, int root = 0) const { ; } 
+
+    template <class T>
+    void Bcast (Array<T> & d, int root = 0) { ; } 
+
+    template <typename T>
+    void AllGather (T val, FlatArray<T> recv) const
+    {
+      recv[0] = val;
+    }
+
+    template <typename T>
+    void ExchangeTable (DynamicTable<T> & send_data, 
+                        DynamicTable<T> & recv_data, int tag) { ; }
+
+    
+    NgMPI_Comm SubCommunicator (FlatArray<int> procs) const
+    { return *this; }
+  };  
+
+  inline void MyMPI_WaitAll (FlatArray<NG_MPI_Request> requests) { ; }
+  inline int MyMPI_WaitAny (FlatArray<NG_MPI_Request> requests) { return 0; }
+
+  class MyMPI
+  {
+  public:
+    MyMPI(int argc, char ** argv) { ; }
+  };
+
+  
+#endif // PARALLEL
+
 } // namespace ngcore
 
 #endif // NGCORE_MPIWRAPPER_HPP

libsrc/core/ng_mpi.hpp

@@ -1,6 +1,8 @@
 #ifndef NG_MPI_HPP_INCLUDED
 #define NG_MPI_HPP_INCLUDED
 
+#ifdef PARALLEL
+
 #include <cstdint>
 #include <filesystem>
 #include <string>
@@ -84,4 +86,5 @@ NGCORE_API extern py::handle (*NG_MPI_CommToMPI4Py)(NG_MPI_Comm);
 
 }  // namespace ngcore
 
+#endif // PARALLEL
 #endif  // NG_MPI_HPP_INCLUDED

libsrc/core/ng_mpi_wrapper.cpp

@@ -1,3 +1,5 @@
+#ifdef PARALLEL
+
 #include <filesystem>
 #include <iostream>
 #include <stdexcept>
@@ -64,7 +66,7 @@ void InitMPI(std::filesystem::path mpi_lib_path,
     cout << IM(5) << "Have MPICH" << endl;
     libname = std::string("libng_mpich") + NETGEN_SHARED_LIBRARY_SUFFIX;
   } else
-    cerr << "Unknown MPI version, skipping init: " << version_string<< endl;
+    cerr << "Unknown MPI version, skipping init: " << version_string << endl;
 
   if (libname.size()) {
     ng_mpi_lib = std::make_unique<SharedLibrary>(libname);
@@ -89,3 +91,5 @@ decltype(NG_MPI_CommToMPI4Py) NG_MPI_CommToMPI4Py =
 #include "ng_mpi_generated_dummy_init.hpp"
 
 }  // namespace ngcore
+
+#endif  // PARALLEL

libsrc/core/python_ngcore_export.cpp

@@ -37,8 +37,11 @@ PYBIND11_MODULE(pyngcore, m) // NOLINT
 
   ExportTable<int>(m);
 
+  #ifdef PARALLEL
   py::class_<NG_MPI_Comm> (m, "_NG_MPI_Comm")
           ;
+  m.def("InitMPI", &InitMPI);
+  #endif // PARALLEL
 
   py::class_<BitArray, shared_ptr<BitArray>> (m, "BitArray")
     .def(py::init([] (size_t n) { return make_shared<BitArray>(n); }),py::arg("n"))
@@ -338,5 +341,4 @@ threads : int
 	   }, "Returns list of timers"
 	   );
   m.def("ResetTimers", &NgProfiler::Reset);
-  m.def("InitMPI", &InitMPI);
 }