From 4e72dd865a3fc83baa69f6b7c08720a1b546a464 Mon Sep 17 00:00:00 2001
From: Cao Zongyan <zongyan.cao@alibaba-inc.com>
Date: Wed, 29 Aug 2018 17:05:43 +0800
Subject: Refine LeakyRelu codes.

1. Add C++ gradient of gradient definition of LeakyReLu and revalant UT.
2. Using forward compatibility layer for python code changes.
---
 tensorflow/cc/gradients/nn_grad.cc      | 18 ++++++++++++++++--
 tensorflow/cc/gradients/nn_grad_test.cc | 16 ++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

(limited to 'tensorflow/cc')

diff --git a/tensorflow/cc/gradients/nn_grad.cc b/tensorflow/cc/gradients/nn_grad.cc
index 0fc23d0bf7..2a32a2ed6f 100644
--- a/tensorflow/cc/gradients/nn_grad.cc
+++ b/tensorflow/cc/gradients/nn_grad.cc
@@ -149,13 +149,27 @@ Status LeakyReluGradHelper(const Scope& scope, const Operation& op,
   float alpha;
   TF_RETURN_IF_ERROR(GetNodeAttr(op.node()->attrs(), "alpha", &alpha));
   internal::LeakyReluGrad::Attrs attrs;
-  attrs.Alpha(alpha);
-  auto dx = internal::LeakyReluGrad(scope, grad_inputs[0], op.input(0), attrs);
+  auto dx = internal::LeakyReluGrad(scope, grad_inputs[0], op.input(0),
+                                    attrs.Alpha(alpha));
   grad_outputs->push_back(dx);
   return scope.status();
 }
 REGISTER_GRADIENT_OP("LeakyRelu", LeakyReluGradHelper);
 
+Status LeakyReluGradGradHelper(const Scope& scope, const Operation& op,
+                               const std::vector<Output>& grad_inputs,
+                               std::vector<Output>* grad_outputs) {
+  float alpha;
+  TF_RETURN_IF_ERROR(GetNodeAttr(op.node()->attrs(), "alpha", &alpha));
+  internal::LeakyReluGrad::Attrs attrs;
+  auto dx = internal::LeakyReluGrad(scope, grad_inputs[0], op.input(1),
+                                    attrs.Alpha(alpha));
+  grad_outputs->push_back(dx);
+  grad_outputs->push_back(NoGradient());
+  return scope.status();
+}
+REGISTER_GRADIENT_OP("LeakyReluGrad", LeakyReluGradGradHelper);
+
 Status EluGradHelper(const Scope& scope, const Operation& op,
                      const std::vector<Output>& grad_inputs,
                      std::vector<Output>* grad_outputs) {
diff --git a/tensorflow/cc/gradients/nn_grad_test.cc b/tensorflow/cc/gradients/nn_grad_test.cc
index 5ebece7b6e..bf0db1f59d 100644
--- a/tensorflow/cc/gradients/nn_grad_test.cc
+++ b/tensorflow/cc/gradients/nn_grad_test.cc
@@ -17,6 +17,7 @@ limitations under the License.
 #include "tensorflow/cc/framework/gradient_checker.h"
 #include "tensorflow/cc/framework/testutil.h"
 #include "tensorflow/cc/gradients/grad_testutil.h"
+#include "tensorflow/cc/ops/nn_ops_internal.h"
 #include "tensorflow/cc/ops/standard_ops.h"
 #include "tensorflow/core/framework/tensor_testutil.h"
 #include "tensorflow/core/lib/core/status_test_util.h"
@@ -173,6 +174,21 @@ TEST_F(NNGradTest, LeakyReluGrad) {
   RunTest(x, x_init_value, y, shape);
 }
 
+TEST_F(NNGradTest, LeakyReluGradGrad) {
+  TensorShape shape({5, 2});
+  auto x = Placeholder(scope_, DT_FLOAT, Placeholder::Shape(shape));
+  // Avoid input values where Leaky ReLU gradient is not well defined (around
+  // zero).
+  Tensor x_init_value = test::AsTensor<float>(
+      {2.3f, 1.9f, 1.5f, 1.1f, 0.7f, 0.3f, -0.1f, -0.5f, -0.9f, -1.3f},
+      {5, 2});
+  Tensor features = test::AsTensor<float>(
+      {-0.9f, -0.7f, -0.5f, -0.3f, -0.1f, 0.1f, 0.3f, 0.5f, 0.7f, 0.9f},
+      {5, 2});
+  auto y = ops::internal::LeakyReluGrad(scope_, x, features);
+  RunTest(x, x_init_value, y, shape);
+}
+
 TEST_F(NNGradTest, EluGrad) {
   TensorShape shape({5, 2});
   auto x = Placeholder(scope_, DT_FLOAT, Placeholder::Shape(shape));
-- 
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