Add ImageExpandGrad Function.

paddle/function/GemmConvOp.h

@@ -44,6 +44,7 @@ enum ColFormat { kCFO = 0, kOCF = 1 };
  *                 input_channels,
  *                 filter_height,
  *                 filter_width]
+ * TODO(hedaoyuan): Refactor the arguments of the interface with TensorShape.
  */
 template <ColFormat Format, DeviceType Device, class T>
 class Im2ColFunctor {

paddle/gserver/layers/BlockExpandLayer.cpp

@@ -47,6 +47,12 @@ bool BlockExpandLayer::init(const LayerMap& layerMap,
                        .set("strides", strides)
                        .set("paddings", paddings)
                        .set("blocks", blocks));
+    createFunction(backward_,
+                   "ImageExpandGrad",
+                   FuncConfig()
+                       .set("strides", strides)
+                       .set("paddings", paddings)
+                       .set("blocks", blocks));
   }
 
   return true;
@@ -126,12 +132,12 @@ void BlockExpandLayer::forward(PassType passType) {
   }
   start[batchSize] = batchSize * blockNum;
   if (!useGpu_) {
-    TensorShape inputShape({batchSize, channels_, imgSizeH_, imgSizeW_});
+    inputShape_ = TensorShape({batchSize, channels_, imgSizeH_, imgSizeW_});
-    TensorShape outputShape({batchSize, blockNum, blockSize});
+    outputShape_ = TensorShape({batchSize, blockNum, blockSize});
     BufferArgs inputs;
     BufferArgs outputs;
-    inputs.addArg(*getInputValue(0), inputShape);
+    inputs.addArg(*getInputValue(0), inputShape_);
-    outputs.addArg(*getOutputValue(), outputShape, ASSIGN_TO);
+    outputs.addArg(*getOutputValue(), outputShape_, ASSIGN_TO);
     forward_[0]->calc(inputs, outputs);
   }
 }
@@ -144,6 +150,8 @@ void BlockExpandLayer::backward(const UpdateCallback& callback) {
   if (!preGrad) {
     return;
   }
+
+  if (useGpu_) {
     MatrixPtr grad = getOutputGrad();
     MatrixPtr gradTrans = Matrix::create(blockSize, blockNum, false, useGpu_);
     size_t batchSize = preGrad->getHeight();
@@ -180,6 +188,13 @@ void BlockExpandLayer::backward(const UpdateCallback& callback) {
                              1.0,
                              1.0);
     }
+  } else {
+    BufferArgs inputs;
+    BufferArgs outputs;
+    inputs.addArg(*getOutputGrad(), outputShape_);
+    outputs.addArg(*getInputGrad(0), inputShape_, ADD_TO);
+    backward_[0]->calc(inputs, outputs);
+  }
 }
 
 }  // namespace paddle

paddle/gserver/layers/BlockExpandLayer.h

@@ -53,6 +53,9 @@ protected:
   /// auxiliary variable, which saves the transposed output value.
   MatrixPtr outVTrans_;
 
+  TensorShape inputShape_;
+  TensorShape outputShape_;
+
 public:
   explicit BlockExpandLayer(const LayerConfig& config) : Layer(config) {}