diff --git a/paddle/function/cross_map_normal_op.cpp b/paddle/function/cross_map_normal_op.cpp
index 0391a58d89f4afe878edbc6268cb1018f6582f89..a18c0bb750acfe0902bbd7fe0eeda69ffff78a75 100644
--- a/paddle/function/cross_map_normal_op.cpp
+++ b/paddle/function/cross_map_normal_op.cpp
@@ -17,7 +17,6 @@ limitations under the License. */
 
 namespace paddle {
 
-// NCHW
 template <>
 void CrossMapNormal<DEVICE_TYPE_CPU>(real* outputs,
                                      real* denoms,
@@ -36,6 +35,10 @@ void CrossMapNormal<DEVICE_TYPE_CPU>(real* outputs,
   CpuVector inputsV(numSamples * oneSample, inputs);
   CpuVector denomsV(numSamples * oneSample, denoms);
 
+  // f(x) = x * ( 1 + scale * SUM((x)^2) )^(-pow)
+  // x represents inputs
+  // f(x) represents outputs
+  // denoms save the intermediate result for backward
   denomsV = denomsV.constant(1.0);
   const int start = -((int)size - 1) / 2;
   const int end = (int)size + start;
diff --git a/paddle/function/cross_map_normal_op.h b/paddle/function/cross_map_normal_op.h
index f065208084f1d46b2414246b7119ce7d2666e631..e935b26e125d3b9c014d4ae52bfb9474ed31c579 100644
--- a/paddle/function/cross_map_normal_op.h
+++ b/paddle/function/cross_map_normal_op.h
@@ -18,6 +18,22 @@ limitations under the License. */
 
 namespace paddle {
 
+/**
+ * \brief   Cross map respose normalize forward.
+ *          The data structure of image data is NCHW.
+ *
+ * \param[out]  outputs     output data.
+ * \param[in]   denoms      denoms buffer.
+ * \param[in]   inputs      input data.
+ * \param[in]   numSamples  batch size of input image.
+ * \param[in]   channels    number of channel.
+ * \param[in]   height      image height.
+ * \param[in]   width       image width.
+ * \param[in]   size        size.
+ * \param[in]   scale       scale.
+ * \param[in]   pow         scale.
+ *
+ */
 template <DeviceType Device>
 void CrossMapNormal(real* outputs,
                     real* denoms,
@@ -30,6 +46,24 @@ void CrossMapNormal(real* outputs,
                     real scale,
                     real pow);
 
+/**
+ * \brief   Cross map respose normalize backward.
+ *          The data structure of image data is NCHW.
+ *
+ * \param[out]  inputsGrad      input grad.
+ * \param[in]   inputsValue     input value.
+ * \param[out]  outputsValue    output value.
+ * \param[out]  outputsGrad     output grad.
+ * \param[in]   denoms          denoms buffer.
+ * \param[in]   numSamples      batch size of input image.
+ * \param[in]   channels        number of channel.
+ * \param[in]   height          image height.
+ * \param[in]   width           image width.
+ * \param[in]   size            size.
+ * \param[in]   scale           scale.
+ * \param[in]   pow             scale.
+ *
+ */
 template <DeviceType Device>
 void CrossMapNormalGrad(real* inputsGrad,
                         real* inputsValue,
diff --git a/paddle/gserver/layers/Layer.h b/paddle/gserver/layers/Layer.h
index 172e558b82945296ef8a50d464c03efbfd597e0d..16f66a2205f4956291c8aef87b0100c3b685a9f2 100644
--- a/paddle/gserver/layers/Layer.h
+++ b/paddle/gserver/layers/Layer.h
@@ -18,6 +18,7 @@ limitations under the License. */
 #include <functional>
 #include <memory>
 #include "ModelConfig.pb.h"
+#include "paddle/function/Function.h"
 #include "paddle/math/CpuSparseMatrix.h"
 #include "paddle/parameter/Parameter.h"
 #include "paddle/utils/ClassRegistrar.h"
@@ -100,6 +101,11 @@ protected:
   /// Mark input grad in(true) or out(false) of backward function.
   std::vector<bool> markInBackward_;
 
+  /// Layer forward function
+  FunctionBase* forward_;
+  /// Layer backward function
+  FunctionBase* backward_;
+
 public:
   /**
     * Wait until all input value ready.
diff --git a/paddle/gserver/layers/NormProjectionLayer.cpp b/paddle/gserver/layers/NormProjectionLayer.cpp
index 4ff3b805fbb061cbb2630330c1b9b4f6c2b354d6..0f6f9b91d057852d665960411c1d73942925033c 100644
--- a/paddle/gserver/layers/NormProjectionLayer.cpp
+++ b/paddle/gserver/layers/NormProjectionLayer.cpp
@@ -48,20 +48,17 @@ bool CMRProjectionNormLayer::init(const LayerMap& layerMap,
   if (useGpu_) {
     forward_ = FunctionBase::funcRegistrar_.createByType(
         FUNC_NAME(CrossMapNormal, GPU));
+    backward_ = FunctionBase::funcRegistrar_.createByType(
+        FUNC_NAME(CrossMapNormalGrad, GPU));
   } else {
     forward_ = FunctionBase::funcRegistrar_.createByType(
         FUNC_NAME(CrossMapNormal, CPU));
+    backward_ = FunctionBase::funcRegistrar_.createByType(
+        FUNC_NAME(CrossMapNormalGrad, CPU));
   }
   forward_->init(
       FuncConfig().set("size", size_).set("scale", scale_).set("pow", pow_));
 
-  if (useGpu_) {
-    backward_ = FunctionBase::funcRegistrar_.createByType(
-        FUNC_NAME(CrossMapNormalGrad, GPU));
-  } else {
-    backward_ = FunctionBase::funcRegistrar_.createByType(
-        FUNC_NAME(CrossMapNormalGrad, CPU));
-  }
   backward_->init(
       FuncConfig().set("size", size_).set("scale", scale_).set("pow", pow_));
 
@@ -74,7 +71,7 @@ void CMRProjectionNormLayer::forward(PassType passType) {
   /* malloc memory for the output_ if necessary */
   /* note: one sample correspond to one row */
   MatrixPtr input = inputLayers_[0]->getOutputValue();
-  int batchSize = input->getHeight();
+  size_t batchSize = input->getHeight();
   int size = getSize();
   resetOutput(batchSize, size);
 
@@ -82,10 +79,7 @@ void CMRProjectionNormLayer::forward(PassType passType) {
 
   Matrix::resizeOrCreate(denoms_, batchSize, size, /* trans */ false, useGpu_);
 
-  dims_ = {(size_t)batchSize,
-           (size_t)channels_,
-           (size_t)imgSizeH_,
-           (size_t)imgSizeW_};
+  dims_ = {batchSize, channels_, imgSizeH_, imgSizeW_};
   forward_->calc(
       {Tensor(input->getData(), dims_)},
       {Tensor(outV->getData(), dims_), Tensor(denoms_->getData(), dims_)},
diff --git a/paddle/gserver/layers/NormProjectionLayer.h b/paddle/gserver/layers/NormProjectionLayer.h
index 3c4876ece609e70393e92b14d33a9bc6f13136c9..6b2c5dde0d74db4b292d5006d19ce54d3194017e 100644
--- a/paddle/gserver/layers/NormProjectionLayer.h
+++ b/paddle/gserver/layers/NormProjectionLayer.h
@@ -16,7 +16,6 @@ limitations under the License. */
 
 #include <vector>
 #include "NormLayer.h"
-#include "paddle/function/Function.h"
 #include "paddle/math/Matrix.h"
 
 namespace paddle {
@@ -43,7 +42,5 @@ public:
 
 protected:
   Dims dims_;
-  FunctionBase* forward_;
-  FunctionBase* backward_;
 };
 }  // namespace paddle