#1763: fix output shape of flatten rewriter (#1766)

Signed-off-by: Guenther Schmuelling <guschmue@microsoft.com>

Author: guschmue

tf2onnx/onnx_opset/math.py

@@ -203,8 +203,11 @@ class Softmax:
     def version_1(cls, ctx, node, **kwargs):
         # T output = Softmax(T logits). The axis softmax would be performed on is always on -1.
         # T output = Softmax(T input, @int axis). Default axis is 1.
-        logits_rank = len(ctx.get_shape(node.input[0]))
-        node.set_attr("axis", logits_rank - 1)
+        axis = node.get_attr_value("axis")
+        if axis is None:
+            # by default use the last dim
+            axis = len(ctx.get_shape(node.input[0])) - 1
+        node.set_attr("axis", axis)
 
     @classmethod
     def version_11(cls, ctx, node, **kwargs):

tf2onnx/rewriter/flatten_rewriter.py

@@ -85,15 +85,9 @@ def rewrite_flatten(g, ops):
             out_name = utils.port_name(op_name)
             g.make_node("Flatten", [reshape_node.input[0]], outputs=[out_name], name=op_name)
 
-            last_dim = input_shape[-1]
-            sec_last_dim = input_shape[-2]
-            new_dim = None
-            if last_dim > 0 and sec_last_dim > 0:
-                new_dim = last_dim * sec_last_dim
-            else:
-                new_dim = -1
-
-            g.set_shape(out_name, input_shape[:-2] + [new_dim])
+            # take output shape from reshape()
+            output_shape = g.get_shape(reshape_node.output[0])
+            g.set_shape(out_name, output_shape)
             g.replace_all_inputs(reshape_node.output[0], out_name, ops=ops)
             for n in to_remove:
                 g.remove_node(n.name)