deal with scalar tensor

x2paddle/op_mapper/onnx2paddle/opset9/opset.py

@@ -740,26 +740,21 @@ class OpSet9():
     def Unsqueeze(self, node):
         val_x = self.graph.get_input_node(node, idx=0, copy=True)
         axes = node.get_attr('axes')
-        if axes is not None:
-            if len(val_x.out_shapes[0]) == 0 and len(axes) == 1 and axes[
-                    0] == 0:
-                self.paddle_graph.add_layer(
-                    'paddle.reshape',
-                    inputs={"x": val_x.name},
-                    outputs=[node.name],
-                    shape=[1])
-            else:
-                self.paddle_graph.add_layer(
-                    'paddle.unsqueeze',
-                    inputs={"x": val_x.name},
-                    axis=axes,
-                    outputs=[node.name])
+        if axes is None:
+            axes_node = self.graph.get_input_node(node, idx=1, copy=True)
+            axes = _const_weight_or_none(axes_node, necessary=True)
+        # deal with scalar(0D) tensor
+        if len(val_x.out_shapes[0]) == 0 and len(axes) == 1 and axes[0] == 0:
+            self.paddle_graph.add_layer(
+                'paddle.reshape',
+                inputs={"x": val_x.name},
+                outputs=[node.name],
+                shape=[1])
         else:
-            axes = self.graph.get_input_node(node, idx=1, copy=True)
             self.paddle_graph.add_layer(
                 'paddle.unsqueeze',
-                inputs={"x": val_x.name,
-                        "axis": axes.name},
+                inputs={"x": val_x.name},
+                axis=axes,
                 outputs=[node.name])
 
     @print_mapping_info