remove dropout with ratio 1.0

Author: lucienwang1009

tests/test_graph.py

@@ -165,10 +165,9 @@ def test_dropout(self):
             g = process_tf_graph(sess.graph, opset=self.config.opset)
             actual = onnx_to_graphviz(g)
             expected = 'digraph { prob [op_type=Placeholder shape="[]"] input2 [op_type=Placeholder shape="[1, 3]"] ' \
-                       'input1 [op_type=Placeholder shape="[2, 3]"] Add [op_type=Add] Dropout__3 [op_type=Dropout] ' \
-                       'output1 [op_type=Identity] output2 [op_type=Identity] output [op_type=Identity] ' \
-                       'input1:0 -> Add input2:0 -> Add Add:0 -> Dropout__3 Dropout__3:0 -> output1 ' \
-                       'output1:0 -> output2 output2:0 -> output }'
+                       'input1 [op_type=Placeholder shape="[2, 3]"] Add [op_type=Add] output1 [op_type=Identity] ' \
+                       'output2 [op_type=Identity] output [op_type=Identity] input1:0 -> Add input2:0 -> Add ' \
+                       'Add:0 -> output1 output1:0 -> output2 output2:0 -> output }'
             self.assertEqual(expected, actual)
 
     def test_add(self):

tf2onnx/tfonnx.py

@@ -216,6 +216,12 @@ def rewrite_dropout(g, ops):
         for n in set(match.get_nodes()):
             g.remove_node(n.name)
 
+    # remove dropout if its ratio is 1.0
+    for node in g.get_nodes():
+        if node.type == "Dropout" and node.get_attr("ratio").f == 1.0:
+            g.replace_all_inputs(g.get_nodes(), node.output[0], node.input[0])
+            g.remove_node(node.name)
+
     return ops