message: use pinned host buffer in amgx
diff: @@ -207,9 +207,9 @@ void NvidiaAMGX::Solve(Vector &in_x, Vector &in_b)
  AMGX_pin_memory(in_x.HostReadWrite(), in_x.Size()*sizeof(double));
  AMGX_pin_memory(in_b.HostReadWrite(), in_b.Size()*sizeof(double));
  - AMGX_vector_upload(x, in_x.Size(), 1, in_x.ReadWrite());
  + AMGX_vector_upload(x, in_x.Size(), 1, in_x.HostReadWrite());
  - AMGX_vector_upload(b, in_b.Size(), 1, in_b.ReadWrite());
  + AMGX_vector_upload(b, in_b.Size(), 1, in_b.HostReadWrite());
  MPI_Barrier(amgx_comm);
  