flag of early stop and length scalar of decoding

source/sample/transformer/T2TSearch.cpp

@@ -62,6 +62,8 @@ void T2TSearch::Init(int argc, char ** argv)
     LoadParamFloat(argc, argv, "lenalpha", &alpha, 1.0F);
     LoadParamInt(argc, argv, "endid", endSymbols, -1);
     LoadParamInt(argc, argv, "startid", &startSymbol, -1);
+    LoadParamFloat(argc, argv, "maxlenalpha", &scalarMaxLength, 2.0F);
+    LoadParamBool(argc, argv, "earlystop", &isEarlyStop, false);
 
     if(endSymbols[0] >= 0)
         endSymbolNum = 1;
@@ -108,8 +110,8 @@ void T2TSearch::Search(T2TModel * model, XTensor * input, XTensor * padding,
     inputBeam.ReshapeMerged(inputBeam.order - 3);
     paddingBeam.ReshapeMerged(paddingBeam.order - 3);
     
-    /* max output-length = 2 * source-length */
-    int lengthLimit = input->GetDim(-1) * 2;
+    /* max output-length = scalar * source-length */
+    int lengthLimit = (int)(input->GetDim(-1) * scalarMaxLength);
     CheckNTErrors(lengthLimit > 0, "no max length specified!");
     maxLength = lengthLimit;
     

source/sample/transformer/T2TSearch.h

@@ -62,6 +62,12 @@ private:
     /* start symbol */
     int startSymbol;
 
+    /* scalar of the input sequence (for max number of search steps) */
+    float scalarMaxLength;
+
+    /* indicate whether the early stop strategy is used */
+    bool isEarlyStop;
+
 public:
     /* constructor */
     T2TSearch();