update for correct Init in DCGCalculator. (#32)

src/application/application.cpp

@@ -80,7 +80,7 @@ void Application::LoadParameters(int argc, char** argv) {
     config_reader.ReadAllLines();
     if (config_reader.Lines().size() > 0) {
       for (auto& line : config_reader.Lines()) {
-        // remove str after #
+        // remove str after "#"
         if (line.size() > 0 && std::string::npos != line.find_first_of("#")) {
           line.erase(line.find_first_of("#"));
         }

src/metric/dcg_calculator.cpp

@@ -21,7 +21,7 @@ void DCGCalculator::Init(std::vector<double> input_label_gain) {
   label_gain_ = input_label_gain;
   discount_.clear();
   for (data_size_t i = 0; i < kMaxPosition; ++i) {
-    discount_.emplace_back(1.0 / std::log(2.0 + i));
+    discount_.emplace_back(1.0 / std::log2(2.0 + i));
   }
   is_inited_ = true;
 }