modifier const added to getVector method

Summary: In order to use fastText object as a const, we added the const modifier to getVector method.

Reviewed By: EdouardGrave

Differential Revision: D5227866

fbshipit-source-id: 44cc5c60caee22b90b1f789e252eabfc6dbb8131

src/fasttext.cc

@@ -25,7 +25,7 @@ namespace fasttext {
 
 FastText::FastText() : quant_(false) {}
 
-void FastText::getVector(Vector& vec, const std::string& word) {
+void FastText::getVector(Vector& vec, const std::string& word) const {
   const std::vector<int32_t>& ngrams = dict_->getNgrams(word);
   vec.zero();
   for (auto it = ngrams.begin(); it != ngrams.end(); ++it) {

src/fasttext.h

@@ -53,7 +53,7 @@ class FastText {
   public:
     FastText();
 
-    void getVector(Vector&, const std::string&);
+    void getVector(Vector&, const std::string&) const;
     void saveVectors();
     void saveOutput();
     void saveModel();