[LEARNER] Init learner interface

src/gbm/gblinear.cc

@@ -206,7 +206,7 @@ class GBLinear : public GradientBooster {
     LOG(FATAL) << "gblinear does not support predict leaf index";
   }
 
-  std::vector<std::string> Dump2Text(const FeatureMap& fmap, int option) override {
+  std::vector<std::string> Dump2Text(const FeatureMap& fmap, int option) const override {
     std::stringstream fo("");
     fo << "bias:\n";
     for (int i = 0; i < model.param.num_output_group; ++i) {
@@ -258,13 +258,19 @@ class GBLinear : public GradientBooster {
       fi->Read(&weight);
     }
     // model bias
-    inline float* bias(void) {
+    inline float* bias() {
+      return &weight[param.num_feature * param.num_output_group];
+    }
+    inline const float* bias() const {
       return &weight[param.num_feature * param.num_output_group];
     }
     // get i-th weight
     inline float* operator[](size_t i) {
       return &weight[i * param.num_output_group];
     }
+    inline const float* operator[](size_t i) const {
+      return &weight[i * param.num_output_group];
+    }
   };
   // model field
   Model model;

src/gbm/gbtree.cc

@@ -113,7 +113,11 @@ class GBTree : public GradientBooster {
     for (const auto& up : updaters) {
       up->Init(cfg);
     }
+    if (tparam.nthread != 0) {
+      omp_set_num_threads(tparam.nthread);
+    }
   }
+
   void LoadModel(dmlc::Stream* fi) override {
     CHECK_EQ(fi->Read(&mparam, sizeof(mparam)), sizeof(mparam))
         << "GBTree: invalid model file";
@@ -130,6 +134,7 @@ class GBTree : public GradientBooster {
     }
     this->ResetPredBuffer(0);
   }
+
   void SaveModel(dmlc::Stream* fo) const override {
     CHECK_EQ(mparam.num_trees, static_cast<int>(trees.size()));
     // not save predict buffer.
@@ -143,6 +148,7 @@ class GBTree : public GradientBooster {
       fo->Write(dmlc::BeginPtr(tree_info), sizeof(int) * tree_info.size());
     }
   }
+
   void InitModel() override {
     CHECK(mparam.num_trees == 0 && trees.size() == 0)
         << "Model has already been initialized.";
@@ -151,6 +157,7 @@ class GBTree : public GradientBooster {
     pred_buffer.resize(mparam.PredBufferSize(), 0.0f);
     pred_counter.resize(mparam.PredBufferSize(), 0);
   }
+
   void ResetPredBuffer(size_t num_pbuffer) override {
     mparam.num_pbuffer = static_cast<int64_t>(num_pbuffer);
     pred_buffer.clear();
@@ -158,10 +165,12 @@ class GBTree : public GradientBooster {
     pred_buffer.resize(mparam.PredBufferSize(), 0.0f);
     pred_counter.resize(mparam.PredBufferSize(), 0);
   }
+
   bool AllowLazyCheckPoint() const override {
     return mparam.num_output_group == 1 ||
         tparam.updater_seq.find("distcol") != std::string::npos;
   }
+
   void DoBoost(DMatrix* p_fmat,
                int64_t buffer_offset,
                std::vector<bst_gpair>* in_gpair) override {
@@ -191,6 +200,7 @@ class GBTree : public GradientBooster {
       this->CommitModel(std::move(new_trees[gid]), gid);
     }
   }
+
   void Predict(DMatrix* p_fmat,
                int64_t buffer_offset,
                std::vector<float>* out_preds,
@@ -230,6 +240,7 @@ class GBTree : public GradientBooster {
       }
     }
   }
+
   void Predict(const SparseBatch::Inst& inst,
                std::vector<float>* out_preds,
                unsigned ntree_limit,
@@ -246,9 +257,10 @@ class GBTree : public GradientBooster {
                  ntree_limit);
     }
   }
+
   void PredictLeaf(DMatrix* p_fmat,
                    std::vector<float>* out_preds,
-                   unsigned ntree_limit) {
+                   unsigned ntree_limit) override {
     int nthread;
     #pragma omp parallel
     {
@@ -257,7 +269,8 @@ class GBTree : public GradientBooster {
     InitThreadTemp(nthread);
     this->PredPath(p_fmat, out_preds, ntree_limit);
   }
-  std::vector<std::string> Dump2Text(const FeatureMap& fmap, int option) {
+
+  std::vector<std::string> Dump2Text(const FeatureMap& fmap, int option) const override {
     std::vector<std::string> dump;
     for (size_t i = 0; i < trees.size(); i++) {
       dump.push_back(trees[i]->Dump2Text(fmap, option & 1));