fix apache#18938

r3stl355 · Feb 5, 2021 · f8492e8 · f8492e8
1 parent 65beccd
commit f8492e8
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diff --git a/src/operator/sequence_last-inl.h b/src/operator/sequence_last-inl.h
@@ -153,6 +153,10 @@ class SequenceLastOp : public Operator {
     auto d1 = in_data[seq_last::kData].size(1);
     auto dsize = in_data[seq_last::kData].Size();
 
+    if (dsize == 0) {
+      return;  // noop if any input dimension is zero-sized, out_data is of a right shape
+    }
+
     auto batch = (axis != 0) ? d0 : d1;
     auto max_seq_len = in_data[seq_last::kData].size(axis);
     auto rest_size = dsize / (d0 * d1);

diff --git a/tests/python/unittest/test_operator.py b/tests/python/unittest/test_operator.py
@@ -9428,3 +9428,11 @@ def test_sldwin_atten_op_impl(batch_size, seq_length, num_heads,
             test_sldwin_atten_op_impl(2, 128, 2, 8, 16, symmetric, d)
             test_sldwin_atten_op_impl(1, 8, 2, 4, 2, symmetric, d)
 
+def test_zero_sized_dim():
+    """Test for issue: https://github.com/apache/incubator-mxnet/issues/18938"""
+    mx.util.set_np_shape(True)  # Must be done to prevent zero-sized dimension conversion to 'unknown'
+    data = mx.nd.array(np.random.rand(1, 0, 0))
+    res = mx.nd.op.SequenceLast(data)
+    assert data.shape[1:] == res.shape
+    assert len(res) == 0
+