[Bugfix] Handle case where process has no elements to update, in NCCL…

… communicator (dmlc#3035) Co-authored-by: Minjie Wang <[email protected]>
linlinling · Jun 23, 2021 · 7415eaa · 7415eaa
1 parent cb2327d
commit 7415eaa
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/runtime/cuda/nccl_api.cu b/src/runtime/cuda/nccl_api.cu
@@ -176,7 +176,7 @@ std::pair<IdArray, NDArray> SparsePush(
   Workspace<DType> send_value(device, ctx, num_in*num_feat);
 
   // permute the indices and values
-  {
+  if (num_in > 0) {
     const dim3 block(256);
     const dim3 grid((num_in+block.x-1)/block.x);