Request::sendrecv(send_buff, send_count, send_type, rank, tag,
(char *) recv_buff + rank * recv_count * extent, recv_count,
recv_type, rank, tag, comm, &status);
Request::sendrecv(send_buff, send_count, send_type, rank, tag,
(char *) recv_buff + rank * recv_count * extent, recv_count,
recv_type, rank, tag, comm, &status);