MPI_Datatype new_rdtype, new_sdtype;
int new_scounts[2], new_sdispls[2], new_rcounts[2], new_rdispls[2];
const int i_parity = i % 2;
MPI_Datatype new_rdtype, new_sdtype;
int new_scounts[2], new_sdispls[2], new_rcounts[2], new_rdispls[2];
const int i_parity = i % 2;