fix #287

include/LightGBM/bin.h

@@ -136,7 +136,8 @@ public:
   */
   inline std::string bin_info() const {
     std::stringstream str_buf;
-    str_buf << '[' << min_val_ << ',' << max_val_ << ']';
+    str_buf << std::setprecision(std::numeric_limits<double>::digits10 + 2);
+    str_buf << '[' << min_val_ << ':' << max_val_ << ']';
     return str_buf.str();
   }
 

include/LightGBM/dataset.h

@@ -471,6 +471,20 @@ public:
     feature_names_ = std::vector<std::string>(feature_names);
   }
 
+  inline std::vector<std::string> feature_infos() const {
+    std::vector<std::string> bufs;
+    for (int i = 0; i < num_total_features_; i++) {
+      int fidx = used_feature_map_[i];
+      if (fidx == -1) {
+        bufs.push_back("none");
+      } else {
+        const auto bin_mapper = FeatureBinMapper(fidx);
+        bufs.push_back(bin_mapper->bin_info());
+      }
+    }
+    return bufs;
+  }
+
   /*! \brief Get Number of data */
   inline data_size_t num_data() const { return num_data_; }
 

src/boosting/gbdt.cpp

@@ -104,6 +104,8 @@ void GBDT::ResetTrainingData(const BoostingConfig* config, const Dataset* train_
     label_idx_ = train_data->label_idx();
     // get feature names
     feature_names_ = train_data->feature_names();
+
+    feature_infos_ = train_data->feature_infos();
   }
 
   if ((train_data_ != train_data && train_data != nullptr)
@@ -558,6 +560,8 @@ std::string GBDT::SaveModelToString(int num_iterations) const {
 
     ss << "feature_names=" << Common::Join(feature_names_, " ") << std::endl;
 
+    ss << "feature_infos=" << Common::Join(feature_infos_, " ") << std::endl;
+
     ss << std::endl;
     int num_used_model = static_cast<int>(models_.size());
     if (num_iterations > 0) {
@@ -640,6 +644,18 @@ bool GBDT::LoadModelFromString(const std::string& model_str) {
     return false;
   }
 
+  line = Common::FindFromLines(lines, "feature_infos=");
+  if (line.size() > 0) {
+    feature_infos_ = Common::Split(line.substr(std::strlen("feature_infos=")).c_str(), " ");
+    if (feature_infos_.size() != static_cast<size_t>(max_feature_idx_ + 1)) {
+      Log::Fatal("Wrong size of feature_infos");
+      return false;
+    }
+  } else {
+    Log::Fatal("Model file doesn't contain feature infos");
+    return false;
+  }
+
   // get tree models
   size_t i = 0;
   while (i < lines.size()) {

src/boosting/gbdt.h

@@ -329,6 +329,7 @@ protected:
   int num_init_iteration_;
   /*! \brief Feature names */
   std::vector<std::string> feature_names_;
+  std::vector<std::string> feature_infos_;
   /*! \brief number of threads */
   int num_threads_;
   /*! \brief Buffer for multi-threading bagging */