Enable softmax operator for a ngraph engine

test=develop

paddle/fluid/framework/ngraph_bridge.cc

@@ -36,6 +36,8 @@ std::map<std::string,
         {"mean_grad", paddle::operators::ngraphs::BuildMeanGradNode},
         {"mul", paddle::operators::ngraphs::BuildMulNode},
         {"mul_grad", paddle::operators::ngraphs::BuildMulGradNode},
+        {"softmax", paddle::operators::ngraphs::BuildSoftmaxNode},
+        {"softmax_grad", paddle::operators::ngraphs::BuildSoftmaxGradNode},
         {"scale", paddle::operators::ngraphs::BuildScaleNode},
         {"relu", paddle::operators::ngraphs::BuildUnaryNode<ngraph::op::Relu>},
         {"tanh", paddle::operators::ngraphs::BuildUnaryNode<ngraph::op::Tanh>},

paddle/fluid/operators/ngraph/ngraph_ops.h

@@ -26,4 +26,5 @@ limitations under the License. */
 #include "ops/mean_op.h"
 #include "ops/mul_op.h"
 #include "ops/scale_op.h"
+#include "ops/softmax_op.h"
 #include "ops/top_k_op.h"

paddle/fluid/operators/ngraph/ops/softmax_op.h

+/*Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include "ngraph/ngraph.hpp"
+#include "paddle/fluid/operators/ngraph/ops/elementwise_scalar_op.h"
+#include "paddle/fluid/platform/ngraph_helper.h"
+
+namespace paddle {
+namespace operators {
+namespace ngraphs {
+
+void BuildSoftmaxNode(
+    const std::shared_ptr<paddle::framework::OperatorBase>& op,
+    std::shared_ptr<
+        std::unordered_map<std::string, std::shared_ptr<ngraph::Node>>>
+        ngb_node_map) {
+  auto x = paddle::platform::GetInputNode(op, "X", ngb_node_map);
+  auto x_shape = x->get_shape();
+  int rank = x_shape.size();
+  auto x_2d_shape = paddle::platform::FlattenTo2d(x_shape, rank - 1);
+  x = paddle::platform::NgReshaper(x, x_2d_shape);
+
+  auto x_max = std::make_shared<ngraph::op::Max>(x, ngraph::AxisSet{1});
+  auto x_max_bcast = std::make_shared<ngraph::op::Broadcast>(
+      x_max, x_shape, ngraph::AxisSet{1});
+  auto x_shifted = x - x_max_bcast;
+  auto x_clipped =
+      paddle::operators::ngraphs::ElementwiseScalar<ngraph::op::Maximum>(
+          -64., x_shifted);
+  auto softmax =
+      std::make_shared<ngraph::op::Softmax>(x_clipped, ngraph::AxisSet{1});
+  paddle::platform::SetOutputNode(op, "Out", softmax, ngb_node_map);
+}
+
+void BuildSoftmaxGradNode(
+    const std::shared_ptr<paddle::framework::OperatorBase>& op,
+    std::shared_ptr<
+        std::unordered_map<std::string, std::shared_ptr<ngraph::Node>>>
+        ngb_node_map) {
+  auto out = paddle::platform::GetInputNode(op, "Out", ngb_node_map);
+  auto dout = paddle::platform::GetInputNode(op, "Out@GRAD", ngb_node_map);
+  auto out_shape = out->get_shape();
+  int rank = out_shape.size();
+  auto out_2d_shape = paddle::platform::FlattenTo2d(out_shape, rank - 1);
+  auto dout_2d_shape =
+      paddle::platform::FlattenTo2d(dout->get_shape(), rank - 1);
+  out = paddle::platform::NgReshaper(out, out_2d_shape);
+  dout = paddle::platform::NgReshaper(dout, dout_2d_shape);
+
+  auto node_sum =
+      std::make_shared<ngraph::op::Sum>(out * dout, ngraph::AxisSet{1});
+  auto node_bcast = std::make_shared<ngraph::op::Broadcast>(
+      node_sum, out_2d_shape, ngraph::AxisSet{1});
+  auto dx = (dout - node_bcast) * out;
+  paddle::platform::SetOutputNode(op, "X@GRAD", dx, ngb_node_map);
+}
+}  // namespace ngraphs
+}  // namespace operators
+}  // namespace paddle

python/paddle/fluid/tests/unittests/ngraph/test_softmax_ngraph_op.py

+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+import unittest
+from paddle.fluid.tests.unittests.test_softmax_op import TestSoftmaxOp
+
+
+class TestSoftmaxNGRAPHOp(TestSoftmaxOp):
+    def setUp(self):
+        super(TestSoftmaxNGRAPHOp, self).setUp()
+
+
+if __name__ == "__main__":
+    unittest.main()