update with comments

paddle/gserver/layers/SequenceLastInstanceLayer.cpp

@@ -42,7 +42,7 @@ class SequenceLastInstanceLayer : public SequencePoolLayer {
 protected:
   MatrixPtr tmpSrc_;
   MatrixPtr tmpDest_;
-  std::vector<int> insId_;
+  std::vector<int> instanceIds_;
 
 public:
   explicit SequenceLastInstanceLayer(const LayerConfig& config)
@@ -82,10 +82,10 @@ void SequenceLastInstanceLayer::forward(PassType passType) {
     AsyncGpuBlock asyncGpuBlock;
     REGISTER_TIMER_INFO("SequenceLastInstanceLayerForward", getName().c_str());
 
-    insId_.clear();
+    instanceIds_.clear();
     for (size_t seqId = 0; seqId < newBatchSize_; ++seqId) {
       int insId = reversed_ ? starts[seqId] : starts[seqId + 1] - 1;
-      insId_.push_back(insId);
+      instanceIds_.push_back(insId);
 
       outputValue->subMatrix(seqId, 1, tmpDest_)
           ->assign(*(inputValue->subMatrix(insId, 1, tmpSrc_)));
@@ -111,7 +111,7 @@ void SequenceLastInstanceLayer::backward(const UpdateCallback& callback) {
     REGISTER_TIMER_INFO("SequenceLastInstanceLayerBackward", getName().c_str());
 
     for (size_t seqId = 0; seqId < newBatchSize_; ++seqId) {
-      inputGrad->subMatrix(insId_[seqId], 1, tmpDest_)
+      inputGrad->subMatrix(instanceIds_[seqId], 1, tmpDest_)
           ->add(*(outputGrad->subMatrix(seqId, 1, tmpSrc_)));
     }
   }

paddle/gserver/layers/SequencePoolLayer.h

@@ -47,9 +47,9 @@ protected:
   size_t newBatchSize_;
   ICpuGpuVectorPtr startPositions_;
   int stride_;
-  // store the start position of each window
+  // Store the start position of each window.
   IVectorPtr stridePositions_;
-  // Whether the input sequence is reversed or not
+  // Whether the input sequence is reversed or not.
   bool reversed_ = false;
 
 public:

paddle/gserver/tests/test_LayerGrad.cpp

@@ -807,7 +807,7 @@ TEST(Layer, ExpandLayer) {
 void testDegradeLayer(bool hasSubseq,
                       string layer_type,
                       string trans_type,
-                      int stride = -1) {
+                      int stride) {
   TestConfig config;
   config.layerConfig.set_type(layer_type);
   config.layerConfig.set_size(10);
@@ -844,29 +844,33 @@ void testDegradeLayer(bool hasSubseq,
 }
 
 TEST(Layer, MaxLayer) {
-  testDegradeLayer(false, "max", "non-seq");  // seq max to non-seq
-  testDegradeLayer(true, "max", "non-seq");   // hasSubseq max to non-seq
-  testDegradeLayer(true, "max", "seq");       // hasSubseq max to seq
+  testDegradeLayer(false, "max", "non-seq", -1);  // seq max to non-seq
+  testDegradeLayer(true, "max", "non-seq", -1);   // hasSubseq max to non-seq
+  testDegradeLayer(true, "max", "seq", -1);       // hasSubseq max to seq
 }
 
 TEST(Layer, SequenceLastInstanceLayer) {
   testDegradeLayer(false,
                    "seqlastins",
-                   "non-seq");  // seq seqlastins to non-seq
+                   "non-seq",
+                   -1);  // seq seqlastins to non-seq
   testDegradeLayer(false,
                    "seqlastins",
                    "non-seq",
                    5);  // seq seqlastins to a shorten seq, stride window = 5
   testDegradeLayer(true,
                    "seqlastins",
-                   "non-seq");  // hasSubseq seqlastins to non-seq
-  testDegradeLayer(true, "seqlastins", "seq");  // hasSubseq seqlastins to seq
+                   "non-seq",
+                   -1);  // hasSubseq seqlastins to non-seq
+  testDegradeLayer(
+      true, "seqlastins", "seq", -1);  // hasSubseq seqlastins to seq
 }
 
 TEST(Layer, AverageLayer) {
-  testDegradeLayer(false, "average", "non-seq");  // seq average to non-seq
-  testDegradeLayer(true, "average", "non-seq");  // hasSubseq average to non-seq
-  testDegradeLayer(true, "average", "seq");      // hasSubseq average to seq
+  testDegradeLayer(false, "average", "non-seq", -1);  // seq average to non-seq
+  testDegradeLayer(
+      true, "average", "non-seq", -1);           // hasSubseq average to non-seq
+  testDegradeLayer(true, "average", "seq", -1);  // hasSubseq average to seq
 }
 
 TEST(Layer, SequenceConcatLayer) {

paddle/parameter/Argument.cpp

@@ -563,12 +563,11 @@ void Argument::poolSequenceWithStride(const Argument& input,
                                       size_t stride,
                                       IVectorPtr* stridePostions,
                                       bool reversed) {
-  /*
-   * If input.sequenceStartPositions = [0, 9, 14, 17, 30] and stride = 5,
-   * then sequenceStartPositions = [0, 2, 3, 4, 7].
-   * If reversed = false, stridePostions = [0, 5, 9, 14, 17, 22, 27, 30];
-   * else reversed = true, stridePostions = [0, 4, 9, 14, 17, 20, 25, 30]
-   */
+  // If input.sequenceStartPositions = [0, 9, 14, 17, 30] and stride = 5,
+  // then sequenceStartPositions = [0, 2, 3, 4, 7].
+  // If reversed = false, stridePostions = [0, 5, 9, 14, 17, 22, 27, 30];
+  // else reversed = true, stridePostions = [0, 4, 9, 14, 17, 20, 25, 30]
+
   CHECK(input.sequenceStartPositions);
   CHECK_EQ(input.hasSubseq(), 0UL);
   CHECK_GT(stride, 0) << "stride must larger than 0";