Handle null communicators and datatypes in copy constructor

fsgrid.hpp

@@ -570,6 +570,7 @@ template <typename T, int stencil> class FsGrid : public FsGridTools{
 
  // Copy constructor
  FsGrid(const FsGrid& other) : 
+ comm3d {MPI_COMM_NULL},
  rank {other.rank}, 
  DX {other.DX},
  DY {other.DY},
@@ -589,10 +590,19 @@ template <typename T, int stencil> class FsGrid : public FsGridTools{
  coupling {other.coupling},
  data {other.data}
  {
- MPI_Comm_dup(other.comm3d, &comm3d);
+ if (other.comm3d != MPI_COMM_NULL) {
+ MPI_Comm_dup(other.comm3d, &comm3d);
+ }
+
+ neighbourSendType.fill(MPI_DATATYPE_NULL);
+ neighbourReceiveType.fill(MPI_DATATYPE_NULL);
  for (int i = 0; neighbourSendType.size(); ++i) {
- MPI_Type_dup(other.neighbourSendType[i], neighbourSendType.data() + i);
- MPI_Type_dup(other.neighbourReceiveType[i], neighbourReceiveType.data() + i);
+ if (other.neighbourSendType[i] != MPI_DATATYPE_NULL) {
+ MPI_Type_dup(other.neighbourSendType[i], neighbourSendType.data() + i);
+ }
+ if (other.neighbourReceiveType[i] != MPI_DATATYPE_NULL) {
+ MPI_Type_dup(other.neighbourReceiveType[i], neighbourReceiveType.data() + i);
+ }
  }
  }