more human-friendly exception
@@ -78,7 +78,7 @@ namespace NCatboostCuda {
auto& sampledDocs = target->Docs;
target->PointDer2OrWeights.Clear();
- CB_ENSURE(samplesGrouping.GetPairs().GetObjectsSlice().Size());
+ CB_ENSURE(samplesGrouping.GetPairs().GetObjectsSlice().Size(), "No pairs found");
gradient.Reset(point.GetMapping());
sampledDocs.Reset(point.GetMapping());
