!4005 unsortedsegsum grad

Merge pull request !4005 from fangzehua/unsortedsegsum

mindspore/ops/_grad/grad_array_ops.py

@@ -673,6 +673,16 @@ def _GatherDropNegatives(params,
     return (select(is_positive, gathered, zero_slice), zero_clipped_indices, is_positive)
 
 
+@bprop_getters.register(P.UnsortedSegmentSum)
+def get_bprop_unsorted_segment_sum(self):
+    """Generate bprop for UnsortedSegmentSum"""
+
+    def bprop(x, segment_ids, num_segments, out, dout):
+        return _GatherDropNegatives(dout, segment_ids)[0], zeros_like(segment_ids), zeros_like(num_segments)
+
+    return bprop
+
+
 @bprop_getters.register(P.UnsortedSegmentMin)
 def get_bprop_unsorted_segment_min(self):
     """Generate bprop for UnsortedSegmentMin"""

tests/ut/python/ops/test_ops.py

@@ -1448,14 +1448,12 @@ test_case_nn_ops = [
         'block': P.UnsortedSegmentSum(),
         'desc_const': [1280],
         'desc_inputs': [[1280, 1024], Tensor(np.ones(1280).astype(np.int32))],
-        'desc_bprop': [[8192, 1024]],
-        'skip': ['backward']}),
+        'desc_bprop': [[1280, 1024]]}),
     ('UnsortedSegmentSum_1', {
         'block': P.UnsortedSegmentSum(),
         'desc_const': [4],
         'desc_inputs': [[3, 2, 1, 3], Tensor(np.array([[0, 1], [0, 1], [0, 1]]).astype(np.int32))],
-        'desc_bprop': [[4, 1, 3]],
-        'skip': ['backward']}),
+        'desc_bprop': [[4, 1, 3]]}),
     ('UnsortedSegmentMin', {
         'block': P.UnsortedSegmentMin(),
         'desc_const': [4],