Fix fill_constant_batch_size_like_op when input is LoDTensor. (#10943)

paddle/fluid/operators/fill_constant_batch_size_like_op.h

@@ -24,6 +24,14 @@ class FillConstantBatchSizeLikeOpKernel : public framework::OpKernel<T> {
  public:
   void Compute(const framework::ExecutionContext& ctx) const override {
     auto* out = ctx.Output<framework::Tensor>("Out");
+    auto* in = ctx.Input<framework::LoDTensor>("Input");
+    if (in->lod().size() && ctx.Attr<int>("input_dim_idx") == 0) {
+      // set the correct batch size for the LoDTensor.
+      auto odims = out->dims();
+      int output_dim_idx = ctx.Attr<int>("output_dim_idx");
+      odims[output_dim_idx] = static_cast<int>(in->lod().back().size()) - 1;
+      out->mutable_data<T>(odims, ctx.GetPlace());
+    }
     out->mutable_data<T>(ctx.GetPlace());
     auto value = ctx.Attr<float>("value");
 

python/paddle/fluid/tests/unittests/test_fill_constant_batch_size_like_op.py

@@ -50,5 +50,27 @@ class TestFillConstantBatchSizeLikeWhenSecondDimIsBatchSize(OpTest):
         self.check_output()
 
 
+class TestFillConstantBatchSizeLikeWithLoDTensor(OpTest):
+    def setUp(self):
+        self.op_type = "fill_constant_batch_size_like"
+        self.inputs = {
+            'Input': (np.random.random((31, 28)).astype("float32"),
+                      [[0, 9, 23, 31]])
+        }
+        self.attrs = {
+            'value': 3.5,
+            'shape': [-1, 16],
+            'input_dim_idx': 0,
+            'output_dim_idx': 0
+        }
+
+        out = np.random.random((3, 16)).astype("float32")
+        out.fill(3.5)
+        self.outputs = {'Out': out}
+
+    def test_check_output(self):
+        self.check_output()
+
+
 if __name__ == "__main__":
     unittest.main()