Implemented conversion of DynamicStitch

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

Author: TomWildenhain-Microsoft

tests/test_backend.py

@@ -3282,6 +3282,16 @@ def func(data, partitions):
             return p1_, p2_, p3_
         self._run_test_case(func, [_OUTPUT, _OUTPUT1, _OUTPUT2], {_INPUT: data_val, _INPUT1: part_val})
 
+    @check_opset_min_version(11, "ScatterElements")
+    def test_dynamic_stitch_both_vector(self):
+        data_val = np.array([[5, 1, 3], [7, 2, 4]], dtype=np.float32)
+        indices_val = np.array([[0, 1, 4], [2, 3, 5]], dtype=np.int32)
+        def func(indices, data):
+            x = tf.dynamic_stitch(tf.unstack(indices), tf.unstack(data))
+            x_ = tf.identity(x, name=_TFOUTPUT)
+            return x_
+        self._run_test_case(func, [_OUTPUT], {_INPUT: indices_val, _INPUT1: data_val})
+
     @check_opset_min_version(10, "Conv2DBackpropInput")
     def test_Conv2DBackpropInput_const(self):
         input_sizes_val_ = np.array([1, 10, 10, 3], dtype=np.int32)

tf2onnx/onnx_opset/tensor.py

@@ -1818,6 +1818,45 @@ def version_9(cls, ctx, node, **kwargs):
         ctx.remove_node(node.name)
 
 
+@tf_op(["DynamicStitch", "ParallelDynamicStitch"])
+class DynamicStitch:
+    @classmethod
+    def version_10(cls, ctx, node, **kwargs):
+        num_partitions = len(node.input) // 2
+        index_inputs = node.input[:num_partitions]
+        data_inputs = node.input[num_partitions:]
+        index_shapes = [ctx.get_shape(inp) for inp in index_inputs]
+        data_shapes = [ctx.get_shape(inp) for inp in data_inputs]
+        utils.make_sure(all(s is not None and len(s) == 1 for s in index_shapes),
+                        "DynamicPartition only implemented for index tensors of rank 1")
+        utils.make_sure(all(s is not None and len(s) == 1 for s in data_shapes),
+                        "DynamicPartition only implemented for data tensors of rank 1")
+        dtype = ctx.get_dtype(node.output[0])
+        concat_indices = ctx.make_node("Concat", index_inputs, attr={'axis': 0})
+        concat_indices_int64 = ctx.make_node("Cast", [concat_indices.output[0]], attr={"to": TensorProto.INT64})
+
+        concat_data = ctx.make_node("Concat", data_inputs, attr={'axis': 0})
+
+        data_shape = ctx.make_node("Shape", [concat_data.output[0]])
+        expanded_indices = ctx.make_node("Expand", [concat_indices_int64.output[0], data_shape.output[0]])
+
+        max_index = ctx.make_node("ReduceMax", [concat_indices_int64.output[0]], attr={'axes': [0], 'keepdims': 1})
+        const_one = ctx.make_const(utils.make_name('const_one'), np.array([1], np.int64))
+        target_length = ctx.make_node("Add", [max_index.output[0], const_one.output[0]])
+
+        zero_tensor = helper.make_tensor("value", dtype, dims=[1], vals=[0])
+        zeros_of_shape = ctx.make_node("ConstantOfShape", [target_length.output[0]], attr={"value": zero_tensor})
+
+        name = node.name
+        outputs = node.output
+        ctx.remove_node(node.name)
+        ctx.make_node("ScatterElements",
+                      [zeros_of_shape.output[0], expanded_indices.output[0], concat_data.output[0]],
+                      name=name,
+                      outputs=outputs,
+                      attr={'axis': 0})
+
+
 @tf_op("MatrixDiagPart")
 class MatrixDiagPart:
     @classmethod