From b9874251c623a17c7db8c5c3c7214ae8b451a52f Mon Sep 17 00:00:00 2001
From: Tomasz Patejko <tomasz.patejko@intel.com>
Date: Fri, 30 Mar 2018 03:12:33 -0400
Subject: [PATCH] Plain LRN op throws an exception when is_test is set in
 backward pass

---
 paddle/fluid/operators/lrn_op.cc | 5 ++++-
 paddle/fluid/operators/lrn_op.h  | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/paddle/fluid/operators/lrn_op.cc b/paddle/fluid/operators/lrn_op.cc
index b36b5c3a339..cb156839812 100644
--- a/paddle/fluid/operators/lrn_op.cc
+++ b/paddle/fluid/operators/lrn_op.cc
@@ -214,7 +214,10 @@ class LRNOpMaker : public framework::OpProtoAndCheckerMaker {
         "Defaults to \"NHWC\". Specify the data format of the output data, "
         "the input will be transformed automatically. ")
         .SetDefault("AnyLayout");
-    AddAttr<bool>("is_test", "").SetDefault(false);
+    AddAttr<bool>("is_test",
+                  "Turns on memory optimization that optimizes away "
+                  "unnecessary memory allocations. Used by MKLDNN.")
+        .SetDefault(false);
 
     AddComment(R"DOC(
 Local Response Normalization Operator.
diff --git a/paddle/fluid/operators/lrn_op.h b/paddle/fluid/operators/lrn_op.h
index 95796f7eecd..0fd3175e857 100644
--- a/paddle/fluid/operators/lrn_op.h
+++ b/paddle/fluid/operators/lrn_op.h
@@ -121,6 +121,10 @@ class LRNGradKernel : public framework::OpKernel<T> {
     T alpha = ctx.Attr<T>("alpha");
     T beta = ctx.Attr<T>("beta");
 
+    PADDLE_ENFORCE(
+        !ctx.Attr<bool>("is_test"),
+        "is_test attribute should be set to False in training phase.");
+
     LRNGradFunctor<DeviceContext, T> f;
     f(ctx, x, out, mid, x_g, out_g, N, C, H, W, n, alpha, beta);
   }
-- 
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