From 2c2947f80e1b1d3aee6b06acfe993069db021c8b Mon Sep 17 00:00:00 2001
From: dangqingqing <dangqingqing@baidu.com>
Date: Tue, 18 Apr 2017 20:26:34 +0800
Subject: [PATCH] Fix a bug for TransLayer and add unit testing.

---
 paddle/gserver/layers/TransLayer.cpp    |  9 ++++++++-
 paddle/gserver/tests/test_LayerGrad.cpp | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/paddle/gserver/layers/TransLayer.cpp b/paddle/gserver/layers/TransLayer.cpp
index d1fa90f3841..4150f1727d8 100644
--- a/paddle/gserver/layers/TransLayer.cpp
+++ b/paddle/gserver/layers/TransLayer.cpp
@@ -56,7 +56,14 @@ void TransLayer::backward(const UpdateCallback& callback) {
     return;
   }
   MatrixPtr preGrad = getInputGrad(0);
-  outputGrad->transpose(preGrad, false);
+  if (preGrad) {
+    MatrixPtr transGrad = Matrix::create(preGrad->getHeight(),
+                                         preGrad->getWidth(),
+                                         /* trans= */ false,
+                                         preGrad->useGpu());
+    outputGrad->transpose(transGrad, false);
+    preGrad->add(*transGrad);
+  }
 }
 
 }  // namespace paddle
diff --git a/paddle/gserver/tests/test_LayerGrad.cpp b/paddle/gserver/tests/test_LayerGrad.cpp
index 193b876c316..0d7bd8c3b85 100644
--- a/paddle/gserver/tests/test_LayerGrad.cpp
+++ b/paddle/gserver/tests/test_LayerGrad.cpp
@@ -1689,6 +1689,22 @@ TEST(Layer, smooth_l1) {
   }
 }
 
+TEST(Layer, TransLayer) {
+  TestConfig config;
+  const int height = 128;
+  const int width = 1028;
+  config.layerConfig.set_type("trans");
+  config.layerConfig.set_size(width);
+
+  config.inputDefs.push_back(
+      {INPUT_DATA, "layer_0", /* dim= */ height * width, /* paraSize= */ 0});
+  config.layerConfig.add_inputs();
+
+  for (auto useGpu : {false, true}) {
+    testLayerGrad(config, "trans", height, /* trans= */ false, useGpu);
+  }
+}
+
 int main(int argc, char** argv) {
   testing::InitGoogleTest(&argc, argv);
   initMain(argc, argv);
-- 
GitLab