Implementation of XE_NDCG_MART for the ranking task (#2620)

* Implementation of XE_NDCG loss function for ranking.

* Add citation

* Check in example usage for xe_ndcg loss.

* Seed the generator when a seed is provided in the config. Add unit-tests for xe_ndcg

* Update documentation

* Fix indentation

* Address issues raised by reviewers.

* Clean up include statements.

* Fix issues raised by reviewers.

* Regenerate parameters.rst

* Add a note to explain that reproducing xe_ndcg results requires num_threads to be one.

* Introduce objective_seed and use that in rank_xendcg instead of directly using seed

* Change default value of objective_seed

docs/Parameters.rst

@@ -51,7 +51,7 @@ Core Parameters
 
    -  **Note**: can be used only in CLI version; for language-specific packages you can use the correspondent functions
 
--  ``objective`` :raw-html:`<a id="objective" title="Permalink to this parameter" href="#objective">&#x1F517;&#xFE0E;</a>`, default = ``regression``, type = enum, options: ``regression``, ``regression_l1``, ``huber``, ``fair``, ``poisson``, ``quantile``, ``mape``, ``gamma``, ``tweedie``, ``binary``, ``multiclass``, ``multiclassova``, ``cross_entropy``, ``cross_entropy_lambda``, ``lambdarank``, aliases: ``objective_type``, ``app``, ``application``
+-  ``objective`` :raw-html:`<a id="objective" title="Permalink to this parameter" href="#objective">&#x1F517;&#xFE0E;</a>`, default = ``regression``, type = enum, options: ``regression``, ``regression_l1``, ``huber``, ``fair``, ``poisson``, ``quantile``, ``mape``, ``gamma``, ``tweedie``, ``binary``, ``multiclass``, ``multiclassova``, ``cross_entropy``, ``cross_entropy_lambda``, ``lambdarank``, ``rank_xendcg``, aliases: ``objective_type``, ``app``, ``application``
 
    -  regression application
 
@@ -99,6 +99,10 @@ Core Parameters
 
       -  all values in ``label`` must be smaller than number of elements in ``label_gain``
 
+   -  ``rank_xendcg``, `XE_NDCG_MART <https://arxiv.org/abs/1911.09798>`__ ranking objective function, aliases: ``xendcg``, ``xe_ndcg``, ``xe_ndcg_mart``, ``xendcg_mart``
+
+      -  to obtain reproducible results, you should disable parallelism by setting ``num_threads`` to 1
+
 -  ``boosting`` :raw-html:`<a id="boosting" title="Permalink to this parameter" href="#boosting">&#x1F517;&#xFE0E;</a>`, default = ``gbdt``, type = enum, options: ``gbdt``, ``rf``, ``dart``, ``goss``, aliases: ``boosting_type``, ``boost``
 
    -  ``gbdt``, traditional Gradient Boosting Decision Tree, aliases: ``gbrt``
@@ -852,6 +856,12 @@ Objective Parameters
 
    -  separate by ``,``
 
+-  ``objective_seed`` :raw-html:`<a id="objective_seed" title="Permalink to this parameter" href="#objective_seed">&#x1F517;&#xFE0E;</a>`, default = ``5``, type = int
+
+   -  random seed for objectives
+
+   -  used only in the ``rank_xendcg`` objective
+
 Metric Parameters
 -----------------
 

examples/xendcg/README.md

+XE_NDCG Ranking Example
+=======================
+
+Here is an example for LightGBM to train a ranking model with the [XE_NDCG loss](https://arxiv.org/abs/1911.09798).
+
+***You must follow the [installation instructions](https://lightgbm.readthedocs.io/en/latest/Installation-Guide.html)
+for the following commands to work. The `lightgbm` binary must be built and available at the root of this project.***
+
+Training
+--------
+
+Run the following command in this folder:
+
+```bash
+"../../lightgbm" config=train.conf
+```
+
+Prediction
+----------
+
+You should finish training first.
+
+Run the following command in this folder:
+
+```bash
+"../../lightgbm" config=predict.conf
+```
+
+Data Format
+-----------
+
+To learn more about the query format used in this example, check out the 
+[query data format](https://lightgbm.readthedocs.io/en/latest/Parameters.html#query-data).

examples/xendcg/predict.conf

+task = predict
+
+data = rank.test
+
+input_model= LightGBM_model.txt

examples/xendcg/rank.test.query

+12
+19
+18
+10
+15
+15
+22
+23
+18
+16
+16
+11
+6
+13
+17
+21
+20
+16
+13
+16
+21
+15
+10
+19
+10
+13
+18
+17
+23
+24
+16
+13
+17
+24
+17
+10
+17
+15
+18
+16
+9
+9
+21
+14
+13
+13
+13
+10
+10
+6

examples/xendcg/rank.train.query

+1
+13
+5
+8
+19
+12
+18
+5
+14
+13
+8
+9
+16
+11
+21
+14
+21
+9
+14
+11
+20
+18
+13
+20
+22
+22
+13
+17
+10
+13
+12
+13
+13
+23
+18
+13
+20
+12
+22
+14
+13
+23
+13
+14
+14
+5
+13
+15
+14
+14
+16
+16
+15
+21
+22
+10
+22
+18
+25
+16
+12
+12
+15
+15
+25
+13
+9
+12
+8
+16
+25
+19
+24
+12
+16
+10
+16
+9
+17
+15
+7
+9
+15
+14
+16
+17
+8
+17
+12
+18
+23
+10
+12
+12
+4
+14
+12
+15
+27
+16
+20
+13
+19
+13
+17
+17
+16
+12
+15
+14
+14
+19
+12
+23
+18
+16
+9
+23
+11
+15
+8
+10
+10
+16
+11
+15
+22
+16
+17
+23
+16
+22
+17
+14
+12
+14
+20
+15
+17
+15
+15
+22
+9
+21
+9
+17
+16
+15
+13
+13
+15
+14
+18
+21
+14
+17
+15
+14
+16
+12
+17
+19
+16
+11
+18
+11
+13
+14
+9
+16
+15
+16
+25
+9
+13
+22
+16
+18
+20
+14
+11
+9
+16
+19
+19
+11
+11
+13
+14
+14
+13
+16
+6
+21
+16
+12
+16
+11
+24
+12
+10

examples/xendcg/train.conf

+# task type, support train and predict
+task = train
+
+# boosting type, support gbdt for now, alias: boosting, boost
+boosting_type = gbdt
+
+# application type, support following application
+# regression , regression task
+# binary , binary classification task
+# lambdarank , lambdarank task
+# alias: application, app
+objective = rank_xendcg
+
+# eval metrics, support multi metric, delimite by ',' , support following metrics
+# l1 
+# l2 , default metric for regression
+# ndcg , default metric for lambdarank
+# auc 
+# binary_logloss , default metric for binary
+# binary_error
+metric = ndcg
+
+# evaluation position for ndcg metric, alias : ndcg_at
+ndcg_eval_at = 1,3,5
+
+# frequence for metric output
+metric_freq = 1
+
+# true if need output metric for training data, alias: tranining_metric, train_metric
+is_training_metric = true
+
+# number of bins for feature bucket, 255 is a recommend setting, it can save memories, and also has good accuracy. 
+max_bin = 255
+
+# training data
+# if exsting weight file, should name to "rank.train.weight"
+# if exsting query file, should name to "rank.train.query"
+# alias: train_data, train
+data = rank.train
+
+# validation data, support multi validation data, separated by ','
+# if exsting weight file, should name to "rank.test.weight"
+# if exsting query file, should name to "rank.test.query"
+# alias: valid, test, test_data, 
+valid_data = rank.test
+
+# number of trees(iterations), alias: num_tree, num_iteration, num_iterations, num_round, num_rounds
+num_trees = 100
+
+# shrinkage rate , alias: shrinkage_rate
+learning_rate = 0.1
+
+# number of leaves for one tree, alias: num_leaf
+num_leaves = 31
+
+# type of tree learner, support following types:
+# serial , single machine version
+# feature , use feature parallel to train
+# data , use data parallel to train
+# voting , use voting based parallel to train
+# alias: tree
+tree_learner = serial
+
+# Set num_threads and objective_seed for stable unit-tests. Comment out otherwise.
+num_threads = 1
+objective_seed = 1025
+
+# feature sub-sample, will random select 80% feature to train on each iteration 
+# alias: sub_feature
+feature_fraction = 1.0
+
+# Support bagging (data sub-sample), will perform bagging every 5 iterations
+bagging_freq = 1
+
+# Bagging farction, will random select 80% data on bagging
+# alias: sub_row
+bagging_fraction = 0.9
+
+# minimal number data for one leaf, use this to deal with over-fit
+# alias : min_data_per_leaf, min_data
+min_data_in_leaf = 50
+
+# minimal sum hessians for one leaf, use this to deal with over-fit
+min_sum_hessian_in_leaf = 5.0
+
+# save memory and faster speed for sparse feature, alias: is_sparse
+is_enable_sparse = true
+
+# when data is bigger than memory size, set this to true. otherwise set false will have faster speed
+# alias: two_round_loading, two_round
+use_two_round_loading = false
+
+# true if need to save data to binary file and application will auto load data from binary file next time
+# alias: is_save_binary, save_binary
+is_save_binary_file = false
+
+# output model file
+output_model = LightGBM_model.txt
+
+# support continuous train from trained gbdt model
+# input_model= trained_model.txt
+
+# output prediction file for predict task
+# output_result= prediction.txt
+
+# support continuous train from initial score file
+# input_init_score= init_score.txt
+
+
+# number of machines in parallel training, alias: num_machine
+num_machines = 1
+
+# local listening port in parallel training, alias: local_port
+local_listen_port = 12400
+
+# machines list file for parallel training, alias: mlist
+machine_list_file = mlist.txt

include/LightGBM/config.h

@@ -102,7 +102,7 @@ struct Config {
 
   // [doc-only]
   // type = enum
-  // options = regression, regression_l1, huber, fair, poisson, quantile, mape, gamma, tweedie, binary, multiclass, multiclassova, cross_entropy, cross_entropy_lambda, lambdarank
+  // options = regression, regression_l1, huber, fair, poisson, quantile, mape, gamma, tweedie, binary, multiclass, multiclassova, cross_entropy, cross_entropy_lambda, lambdarank, rank_xendcg
   // alias = objective_type, app, application
   // desc = regression application
   // descl2 = ``regression``, L2 loss, aliases: ``regression_l2``, ``l2``, ``mean_squared_error``, ``mse``, ``l2_root``, ``root_mean_squared_error``, ``rmse``
@@ -127,6 +127,8 @@ struct Config {
   // descl2 = label should be ``int`` type in lambdarank tasks, and larger number represents the higher relevance (e.g. 0:bad, 1:fair, 2:good, 3:perfect)
   // descl2 = `label_gain <#objective-parameters>`__ can be used to set the gain (weight) of ``int`` label
   // descl2 = all values in ``label`` must be smaller than number of elements in ``label_gain``
+  // desc = ``rank_xendcg``, `XE_NDCG_MART <https://arxiv.org/abs/1911.09798>`__ ranking objective function, aliases: ``xendcg``, ``xe_ndcg``, ``xe_ndcg_mart``, ``xendcg_mart``
+  // descl2 = to obtain reproducible results, you should disable parallelism by setting ``num_threads`` to 1
   std::string objective = "regression";
 
   // [doc-only]
@@ -754,6 +756,10 @@ struct Config {
   // desc = separate by ``,``
   std::vector<double> label_gain;
 
+  // desc = random seed for objectives
+  // desc = used only in the ``rank_xendcg`` objective
+  int objective_seed = 5;
+
   #pragma endregion
 
   #pragma region Metric Parameters
@@ -1004,6 +1010,9 @@ inline std::string ParseObjectiveAlias(const std::string& type) {
     return "cross_entropy_lambda";
   } else if (type == std::string("mean_absolute_percentage_error") || type == std::string("mape")) {
     return "mape";
+  } else if (type == std::string("rank_xendcg") || type == std::string("xendcg") || type == std::string("xe_ndcg")
+             || type == std::string("xe_ndcg_mart") || type == std::string("xendcg_mart")) {
+    return "rank_xendcg";
   } else if (type == std::string("none") || type == std::string("null") || type == std::string("custom") || type == std::string("na")) {
     return "custom";
   }
@@ -1019,7 +1028,8 @@ inline std::string ParseMetricAlias(const std::string& type) {
     return "l1";
   } else if (type == std::string("binary_logloss") || type == std::string("binary")) {
     return "binary_logloss";
-  } else if (type == std::string("ndcg") || type == std::string("lambdarank")) {
+  } else if (type == std::string("ndcg") || type == std::string("lambdarank") || type == std::string("rank_xendcg")
+             || type == std::string("xendcg") || type == std::string("xe_ndcg") || type == std::string("xe_ndcg_mart") || type == std::string("xendcg_mart")) {
     return "ndcg";
   } else if (type == std::string("map") || type == std::string("mean_average_precision")) {
     return "map";

src/io/config.cpp

@@ -192,6 +192,7 @@ void Config::Set(const std::unordered_map<std::string, std::string>& params) {
     bagging_seed = static_cast<int>(rand.NextShort(0, int_max));
     drop_seed = static_cast<int>(rand.NextShort(0, int_max));
     feature_fraction_seed = static_cast<int>(rand.NextShort(0, int_max));
+    objective_seed = static_cast<int>(rand.NextShort(0, int_max));
   }
 
   GetTaskType(params, &task);

src/io/config_auto.cpp

@@ -272,6 +272,7 @@ std::unordered_set<std::string> Config::parameter_set({
   "max_position",
   "lambdamart_norm",
   "label_gain",
+  "objective_seed",
   "metric",
   "metric_freq",
   "is_provide_training_metric",
@@ -553,6 +554,8 @@ void Config::GetMembersFromString(const std::unordered_map<std::string, std::str
     label_gain = Common::StringToArray<double>(tmp_str, ',');
   }
 
+  GetInt(params, "objective_seed", &objective_seed);
+
   GetInt(params, "metric_freq", &metric_freq);
   CHECK(metric_freq >0);
 
@@ -688,6 +691,7 @@ std::string Config::SaveMembersToString() const {
   str_buf << "[max_position: " << max_position << "]\n";
   str_buf << "[lambdamart_norm: " << lambdamart_norm << "]\n";
   str_buf << "[label_gain: " << Common::Join(label_gain, ",") << "]\n";
+  str_buf << "[objective_seed: " << objective_seed << "]\n";
   str_buf << "[metric_freq: " << metric_freq << "]\n";
   str_buf << "[is_provide_training_metric: " << is_provide_training_metric << "]\n";
   str_buf << "[eval_at: " << Common::Join(eval_at, ",") << "]\n";

src/objective/objective_function.cpp

@@ -7,6 +7,7 @@
 #include "binary_objective.hpp"
 #include "multiclass_objective.hpp"
 #include "rank_objective.hpp"
+#include "rank_xendcg_objective.hpp"
 #include "regression_objective.hpp"
 #include "xentropy_objective.hpp"
 
@@ -29,6 +30,8 @@ ObjectiveFunction* ObjectiveFunction::CreateObjectiveFunction(const std::string&
     return new BinaryLogloss(config);
   } else if (type == std::string("lambdarank")) {
     return new LambdarankNDCG(config);
+  } else if (type == std::string("rank_xendcg")) {
+    return new RankXENDCG(config);
   } else if (type == std::string("multiclass")) {
     return new MulticlassSoftmax(config);
   } else if (type == std::string("multiclassova")) {
@@ -68,6 +71,8 @@ ObjectiveFunction* ObjectiveFunction::CreateObjectiveFunction(const std::string&
     return new BinaryLogloss(strs);
   } else if (type == std::string("lambdarank")) {
     return new LambdarankNDCG(strs);
+  } else if (type == std::string("rank_xendcg")) {
+    return new RankXENDCG(strs);
   } else if (type == std::string("multiclass")) {
     return new MulticlassSoftmax(strs);
   } else if (type == std::string("multiclassova")) {

src/objective/rank_xendcg_objective.hpp

+/*!
+ * Copyright (c) 2019 Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See LICENSE file in the project root for license information.
+ */
+#ifndef LIGHTGBM_OBJECTIVE_RANK_XENDCG_OBJECTIVE_HPP_
+#define LIGHTGBM_OBJECTIVE_RANK_XENDCG_OBJECTIVE_HPP_
+
+#include <LightGBM/objective_function.h>
+#include <LightGBM/utils/common.h>
+#include <LightGBM/utils/random.h>
+
+#include <string>
+#include <vector>
+
+namespace LightGBM {
+/*!
+* \brief Implementation of the learning-to-rank objective function, XE_NDCG [arxiv.org/abs/1911.09798].
+*/
+class RankXENDCG: public ObjectiveFunction {
+ public:
+  explicit RankXENDCG(const Config& config) {
+    rand_ = new Random(config.objective_seed);
+  }
+
+  explicit RankXENDCG(const std::vector<std::string>&) {
+    rand_ = new Random();
+  }
+
+  ~RankXENDCG() {
+  }
+  void Init(const Metadata& metadata, data_size_t) override {
+    // get label
+    label_ = metadata.label();
+    // get boundries
+    query_boundaries_ = metadata.query_boundaries();
+    if (query_boundaries_ == nullptr) {
+      Log::Fatal("RankXENDCG tasks require query information");
+    }
+    num_queries_ = metadata.num_queries();
+  }
+
+  void GetGradients(const double* score, score_t* gradients,
+                    score_t* hessians) const override {
+    #pragma omp parallel for schedule(guided)
+    for (data_size_t i = 0; i < num_queries_; ++i) {
+      GetGradientsForOneQuery(score, gradients, hessians, i);
+    }
+  }
+
+  inline void GetGradientsForOneQuery(
+      const double* score,
+      score_t* lambdas, score_t* hessians, data_size_t query_id) const {
+    // get doc boundary for current query
+    const data_size_t start = query_boundaries_[query_id];
+    const data_size_t cnt =
+      query_boundaries_[query_id + 1] - query_boundaries_[query_id];
+    // add pointers with offset
+    const label_t* label = label_ + start;
+    score += start;
+    lambdas += start;
+    hessians += start;
+
+    // Turn scores into a probability distribution using Softmax.
+    std::vector<double> rho(cnt);
+    Common::Softmax(score, &rho[0], cnt);
+
+    // Prepare a vector of gammas, a parameter of the loss.
+    std::vector<double> gammas(cnt);
+    for (data_size_t i = 0; i < cnt; ++i) {
+      gammas[i] = rand_->NextFloat();
+    }
+
+    // Skip query if sum of labels is 0.
+    float sum_labels = 0;
+    for (data_size_t i = 0; i < cnt; ++i) {
+      sum_labels += phi(label[i], gammas[i]);
+    }
+    if (sum_labels == 0) {
+      return;
+    }
+
+    // Approximate gradients and inverse Hessian.
+    // First order terms.
+    std::vector<double> L1s(cnt);
+    for (data_size_t i = 0; i < cnt; ++i) {
+      L1s[i] = -phi(label[i], gammas[i])/sum_labels + rho[i];
+    }
+    // Second-order terms.
+    std::vector<double> L2s(cnt);
+    for (data_size_t i = 0; i < cnt; ++i) {
+      for (data_size_t j = 0; j < cnt; ++j) {
+        if (i == j) continue;
+        L2s[i] += L1s[j] / (1 - rho[j]);
+      }
+    }
+    // Third-order terms.
+    std::vector<double> L3s(cnt);
+    for (data_size_t i = 0; i < cnt; ++i) {
+      for (data_size_t j = 0; j < cnt; ++j) {
+        if (i == j) continue;
+        L3s[i] += rho[j] * L2s[j] / (1 - rho[j]);
+      }
+    }
+
+    // Finally, prepare lambdas and hessians.
+    for (data_size_t i = 0; i < cnt; ++i) {
+      lambdas[i] = static_cast<score_t>(
+          L1s[i] + rho[i]*L2s[i] + rho[i]*L3s[i]);
+      hessians[i] = static_cast<score_t>(rho[i] * (1.0 - rho[i]));
+    }
+  }
+
+  double phi(const label_t l, double g) const {
+    return Common::Pow(2, l) - g;
+  }
+
+  const char* GetName() const override {
+    return "rank_xendcg";
+  }
+
+  std::string ToString() const override {
+    std::stringstream str_buf;
+    str_buf << GetName();
+    return str_buf.str();
+  }
+
+  bool NeedAccuratePrediction() const override { return false; }
+
+ private:
+  /*! \brief Number of queries */
+  data_size_t num_queries_;
+  /*! \brief Pointer of label */
+  const label_t* label_;
+  /*! \brief Query boundries */
+  const data_size_t* query_boundaries_;
+  /*! \brief Pseudo-random number generator */
+  Random* rand_;
+};
+
+}  // namespace LightGBM
+#endif   // LightGBM_OBJECTIVE_RANK_XENDCG_OBJECTIVE_HPP_

tests/python_package_test/test_consistency.py

@@ -110,3 +110,15 @@ class TestEngine(unittest.TestCase):
         sk_pred = gbm.predict(X_test)
         fd.train_predict_check(lgb_train, X_test, X_test_fn, sk_pred)
         fd.file_load_check(lgb_train, '.train')
+
+    def test_xendcg(self):
+        fd = FileLoader('../../examples/xendcg', 'rank')
+        X_train, y_train, _ = fd.load_dataset('.train', is_sparse=True)
+        X_test, _, X_test_fn = fd.load_dataset('.test', is_sparse=True)
+        group_train = fd.load_field('.train.query')
+        lgb_train = lgb.Dataset(X_train, y_train, group=group_train)
+        gbm = lgb.LGBMRanker(**fd.params)
+        gbm.fit(X_train, y_train, group=group_train)
+        sk_pred = gbm.predict(X_test)
+        fd.train_predict_check(lgb_train, X_test, X_test_fn, sk_pred)
+        fd.file_load_check(lgb_train, '.train')

tests/python_package_test/test_sklearn.py

@@ -117,6 +117,21 @@ class TestSklearn(unittest.TestCase):
         self.assertGreater(gbm.best_score_['valid_0']['ndcg@1'], 0.6333)
         self.assertGreater(gbm.best_score_['valid_0']['ndcg@3'], 0.6048)
 
+    def test_xendcg(self):
+        dir_path = os.path.dirname(os.path.realpath(__file__))
+        X_train, y_train = load_svmlight_file(os.path.join(dir_path, '../../examples/xendcg/rank.train'))
+        X_test, y_test = load_svmlight_file(os.path.join(dir_path, '../../examples/xendcg/rank.test'))
+        q_train = np.loadtxt(os.path.join(dir_path, '../../examples/xendcg/rank.train.query'))
+        q_test = np.loadtxt(os.path.join(dir_path, '../../examples/xendcg/rank.test.query'))
+        gbm = lgb.LGBMRanker(n_estimators=50, objective='rank_xendcg', random_state=5, n_jobs=1)
+        gbm.fit(X_train, y_train, group=q_train, eval_set=[(X_test, y_test)],
+                eval_group=[q_test], eval_at=[1, 3], early_stopping_rounds=10, verbose=False,
+                eval_metric='ndcg',
+                callbacks=[lgb.reset_parameter(learning_rate=lambda x: max(0.01, 0.1 - 0.01 * x))])
+        self.assertLessEqual(gbm.best_iteration_, 24)
+        self.assertGreater(gbm.best_score_['valid_0']['ndcg@1'], 0.6579)
+        self.assertGreater(gbm.best_score_['valid_0']['ndcg@3'], 0.6421)
+
     def test_regression_with_custom_objective(self):
         X, y = load_boston(True)
         X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.1, random_state=42)

windows/LightGBM.vcxproj

@@ -237,6 +237,7 @@
     <ClInclude Include="..\src\network\socket_wrapper.hpp" />
     <ClInclude Include="..\src\objective\binary_objective.hpp" />
     <ClInclude Include="..\src\objective\rank_objective.hpp" />
+    <ClInclude Include="..\src\objective\rank_xendcg_objective.hpp" />
     <ClInclude Include="..\src\objective\regression_objective.hpp" />
     <ClInclude Include="..\src\objective\multiclass_objective.hpp" />
     <ClInclude Include="..\src\objective\xentropy_objective.hpp" />
@@ -284,4 +285,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>
\ No newline at end of file

windows/LightGBM.vcxproj.filters

@@ -87,6 +87,9 @@
     <ClInclude Include="..\src\objective\rank_objective.hpp">
       <Filter>src\objective</Filter>
     </ClInclude>
+    <ClInclude Include="..\src\objective\rank_xendcg_objective.hpp">
+      <Filter>src\objective</Filter>
+    </ClInclude>
     <ClInclude Include="..\src\objective\regression_objective.hpp">
       <Filter>src\objective</Filter>
     </ClInclude>
@@ -306,4 +309,4 @@
       <Filter>src\io</Filter>
     </ClCompile>
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file