change some c_api interfaces for better compatibility

include/LightGBM/boosting.h

@@ -151,6 +151,7 @@ public:
   /*! \brief Disable copy */
   Boosting(const Boosting&) = delete;
 
+  static void LoadFileToBoosting(Boosting* boosting, const char* filename);
   /*!
   * \brief Create boosting object
   * \param type Type of boosting

include/LightGBM/c_api.h

@@ -165,7 +165,7 @@ DllExport int LGBM_DatasetSaveBinary(DatesetHandle handle,
 * \param field_name field name, can be label, weight, group
 * \param field_data pointer to vector
 * \param num_element number of element in field_data
-* \param type float_32:0, int32_t:1
+* \param type float32 or int32
 * \return 0 when success, -1 when failure happens
 */
 DllExport int LGBM_DatasetSetField(DatesetHandle handle,
@@ -180,7 +180,7 @@ DllExport int LGBM_DatasetSetField(DatesetHandle handle,
 * \param field_name field name
 * \param out_len used to set result length
 * \param out_ptr pointer to the result
-* \param out_type  float_32:0, int32_t:1
+* \param out_type  float32 or int32
 * \return 0 when success, -1 when failure happens
 */
 DllExport int LGBM_DatasetGetField(DatesetHandle handle,
@@ -216,6 +216,7 @@ DllExport int LGBM_DatasetGetNumFeature(DatesetHandle handle,
 * \param valid_names names of validation data sets
 * \param n_valid_datas number of validation set
 * \param parameters format: 'key1=value1 key2=value2'
+* \param init_model_filename filename of model
 * \prama out handle of created Booster
 * \return 0 when success, -1 when failure happens
 */
@@ -224,6 +225,7 @@ DllExport int LGBM_BoosterCreate(const DatesetHandle train_data,
   const char* valid_names[],
   int n_valid_datas,
   const char* parameters,
+  const char* init_model_filename,
   BoosterHandle* out);
 
 /*!
@@ -232,7 +234,7 @@ DllExport int LGBM_BoosterCreate(const DatesetHandle train_data,
 * \param out handle of created Booster
 * \return 0 when success, -1 when failure happens
 */
-DllExport int LGBM_BoosterLoadFromModelfile(
+DllExport int LGBM_BoosterCreateFromModelfile(
   const char* filename,
   BoosterHandle* out);
 

include/LightGBM/dataset.h

@@ -83,6 +83,8 @@ public:
 
   void SetQueryBoundaries(const data_size_t* query_boundaries, data_size_t len);
 
+  void SetQueryId(const data_size_t* query_id, data_size_t len);
+
   /*!
   * \brief Set initial scores
   * \param init_score Initial scores, this class will manage memory for init_score.

src/boosting/boosting.cpp

@@ -15,7 +15,7 @@ BoostingType GetBoostingTypeFromModelFile(const char* filename) {
   return BoostingType::kUnknow;
 }
 
-void LoadFileToBoosting(Boosting* boosting, const char* filename) {
+void Boosting::LoadFileToBoosting(Boosting* boosting, const char* filename) {
   if (boosting != nullptr) {
     TextReader<size_t> model_reader(filename, true);
     model_reader.ReadAllLines();

src/c_api.cpp

@@ -82,11 +82,12 @@ public:
         Common::ConstPtrInVectorWrapper<Metric>(valid_metrics_[i]));
     }
   }
-
+  void LoadModelFromFile(const char* filename) {
+    Boosting::LoadFileToBoosting(boosting_.get(), filename);
+  }
   ~Booster() {
 
   }
-
   bool TrainOneIter() {
     return boosting_->TrainOneIter(nullptr, nullptr, false);
   }
@@ -414,6 +415,7 @@ DllExport int LGBM_BoosterCreate(const DatesetHandle train_data,
   const char* valid_names[],
   int n_valid_datas,
   const char* parameters,
+  const char* init_model_filename,
   BoosterHandle* out) {
   API_BEGIN();
   const Dataset* p_train_data = reinterpret_cast<const Dataset*>(train_data);
@@ -423,11 +425,15 @@ DllExport int LGBM_BoosterCreate(const DatesetHandle train_data,
     p_valid_datas.emplace_back(reinterpret_cast<const Dataset*>(valid_datas[i]));
     p_valid_names.emplace_back(valid_names[i]);
   }
-  *out = new Booster(p_train_data, p_valid_datas, p_valid_names, parameters);
+  auto ret = std::unique_ptr<Booster>(new Booster(p_train_data, p_valid_datas, p_valid_names, parameters));
+  if (init_model_filename != nullptr) {
+    ret->LoadModelFromFile(init_model_filename);
+  }
+  *out = ret.release();
   API_END();
 }
 
-DllExport int LGBM_BoosterLoadFromModelfile(
+DllExport int LGBM_BoosterCreateFromModelfile(
   const char* filename,
   BoosterHandle* out) {
   API_BEGIN();

src/io/dataset.cpp

@@ -78,6 +78,8 @@ bool Dataset::SetIntField(const char* field_name, const int* field_data, data_si
   name = Common::Trim(name);
   if (name == std::string("query") || name == std::string("group")) {
     metadata_.SetQueryBoundaries(field_data, num_element);
+  } else if (name == std::string("query_id") || name == std::string("group_id")) {
+    metadata_.SetQueryId(field_data, num_element);
   } else {
     return false;
   }

src/io/metadata.cpp

@@ -248,6 +248,39 @@ void Metadata::SetQueryBoundaries(const data_size_t* query_boundaries, data_size
   LoadQueryWeights();
 }
 
+void Metadata::SetQueryId(const data_size_t* query_id, data_size_t len) {
+  if (num_data_ != len) {
+    Log::Fatal("len of query id is not same with #data");
+  }
+  if (queries_.size() > 0) { queries_.clear(); }
+  queries_ = std::vector<data_size_t>(num_data_);
+  for (data_size_t i = 0; i < num_weights_; ++i) {
+    queries_[i] = query_id[i];
+  }
+  // need convert query_id to boundaries
+  std::vector<data_size_t> tmp_buffer;
+  data_size_t last_qid = -1;
+  data_size_t cur_cnt = 0;
+  for (data_size_t i = 0; i < num_data_; ++i) {
+    if (last_qid != queries_[i]) {
+      if (cur_cnt > 0) {
+        tmp_buffer.push_back(cur_cnt);
+      }
+      cur_cnt = 0;
+      last_qid = queries_[i];
+    }
+    ++cur_cnt;
+  }
+  tmp_buffer.push_back(cur_cnt);
+  query_boundaries_ = std::vector<data_size_t>(tmp_buffer.size() + 1);
+  num_queries_ = static_cast<data_size_t>(tmp_buffer.size());
+  query_boundaries_[0] = 0;
+  for (size_t i = 0; i < tmp_buffer.size(); ++i) {
+    query_boundaries_[i + 1] = query_boundaries_[i] + tmp_buffer[i];
+  }
+  queries_.clear();
+  LoadQueryWeights();
+}
 
 void Metadata::LoadWeights() {
   num_weights_ = 0;

tests/c_api_test/test.py

@@ -178,7 +178,7 @@ def test_booster():
     name = [c_str('test')]
     booster = ctypes.c_void_p()
     LIB.LGBM_BoosterCreate(train, c_array(ctypes.c_void_p, test), c_array(ctypes.c_char_p, name), 
-        len(test), c_str("app=binary metric=auc num_leaves=31 verbose=0"), ctypes.byref(booster))
+        len(test), c_str("app=binary metric=auc num_leaves=31 verbose=0"),None, ctypes.byref(booster))
     is_finished = ctypes.c_int(0)
     for i in range(100):
         LIB.LGBM_BoosterUpdateOneIter(booster,ctypes.byref(is_finished))
@@ -191,7 +191,7 @@ def test_booster():
     test_free_dataset(train)
     test_free_dataset(test[0])
     booster2 = ctypes.c_void_p()
-    LIB.LGBM_BoosterLoadFromModelfile(c_str('model.txt'), ctypes.byref(booster2))
+    LIB.LGBM_BoosterCreateFromModelfile(c_str('model.txt'), ctypes.byref(booster2))
     data = []
     inp = open('../../examples/binary_classification/binary.test', 'r')
     for line in inp.readlines():
@@ -214,4 +214,3 @@ def test_booster():
 
 test_dataset()
 test_booster()
-