From e916556beb52e561856e2c8354f3ccf3c852d84d Mon Sep 17 00:00:00 2001
From: Kai Sasaki <lewuathe@me.com>
Date: Wed, 6 Jun 2018 00:18:23 +0900
Subject: [PATCH] Fix clipByValue gradient for values less than min or greater
 than max (#1076)

BUG
---
 src/ops/unary_ops.ts      |  6 ++----
 src/ops/unary_ops_test.ts | 12 ++++++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/ops/unary_ops.ts b/src/ops/unary_ops.ts
index 0150910e8d..fd7380adaf 100644
--- a/src/ops/unary_ops.ts
+++ b/src/ops/unary_ops.ts
@@ -357,11 +357,9 @@ export class UnaryOps {
 
     const grad = (dy: T) => {
       return {
-        // TODO(cais): Fix gradients for the case where x = min or x
-        // = max.
         x: () => dy.where(
-                     x.greater(ops.scalar(clipValueMin))
-                         .logicalAnd(x.less(ops.scalar(clipValueMax))),
+                     x.greaterEqual(ops.scalar(clipValueMin))
+                         .logicalAnd(x.lessEqual(ops.scalar(clipValueMax))),
                      zerosLike(dy)) as T,
       };
     };
diff --git a/src/ops/unary_ops_test.ts b/src/ops/unary_ops_test.ts
index 5b332201fa..acda7df149 100644
--- a/src/ops/unary_ops_test.ts
+++ b/src/ops/unary_ops_test.ts
@@ -2090,6 +2090,18 @@ describeWithFlags('clip', ALL_ENVS, () => {
     expectArraysClose(gradients, [0, 0, 500]);
   });
 
+  it('derivative: 1D tensor with max or min value', () => {
+    const min = -1;
+    const max = 2;
+    const x = tf.tensor1d([-1, 1, 2, 3]);
+    const dy = tf.tensor1d([1, 10, 100, 1000]);
+    const gradients = tf.grad(x => x.clipByValue(min, max))(x, dy);
+
+    expect(gradients.shape).toEqual(x.shape);
+    expect(gradients.dtype).toEqual('float32');
+    expectArraysClose(gradients, [1, 10, 100, 0]);
+  });
+
   it('derivative: scalar', () => {
     const min = -1;
     const max = 2;