fix offset in score_updater.

src/boosting/score_updater.hpp

@@ -52,17 +52,17 @@ public:
   inline bool has_init_score() const { return has_init_score_; }
 
   inline void AddScore(double val, int cur_tree_id) {
-    int64_t offset = cur_tree_id * num_data_;
+    const size_t offset = static_cast<size_t>(num_data_) * cur_tree_id;
     #pragma omp parallel for schedule(static)
-    for (int64_t i = 0; i < num_data_; ++i) {
+    for (int i = 0; i < num_data_; ++i) {
       score_[offset + i] += val;
     }
   }
 
   inline void MultiplyScore(double val, int cur_tree_id) {
-    int64_t offset = cur_tree_id * num_data_;
+    const size_t offset = static_cast<size_t>(num_data_) * cur_tree_id;
     #pragma omp parallel for schedule(static)
-    for (int64_t i = 0; i < num_data_; ++i) {
+    for (int i = 0; i < num_data_; ++i) {
       score_[offset + i] *= val;
     }
   }