Reorder keras outputs if possible (#1480)

Signed-off-by: Tom Wildenhain <[email protected]>

Author: TomWildenhain-Microsoft

tf2onnx/convert.py

@@ -322,6 +322,11 @@ def from_keras(model, input_signature=None, opset=None, custom_ops=None, custom_
     initialized_tables = None
     tensors_to_rename = tensor_names_from_structed(concrete_func, input_names, output_names)
 
+    if model.output_names:
+        # model.output_names is an optional field of Keras models indicating output order. It is None if unused.
+        reverse_lookup = {v: k for k, v in tensors_to_rename.items()}
+        output_names = [reverse_lookup[out] for out in model.output_names]
+
     with tf.device("/cpu:0"):
         frozen_graph = tf_loader.from_function(concrete_func, input_names, output_names, large_model=large_model)
         model_proto, external_tensor_storage = _convert_common(