} else if (req->flags_ & MPI_REQ_RECV) { // apply op on contiguous buffer for accumulate
if (datatype->size() != 0) {
int n = req->real_size_ / datatype->size();
req->op_->apply(req->buf_, req->old_buf_, &n, datatype);
}
} else if (req->flags_ & MPI_REQ_RECV) { // apply op on contiguous buffer for accumulate
if (datatype->size() != 0) {
int n = req->real_size_ / datatype->size();
req->op_->apply(req->buf_, req->old_buf_, &n, datatype);
}