[c++] Segmentation fault when use parallel_tree_learner method when number of categories of one feature larger than 28 (default max_cat_to_onehot-4).

[moming39]

LightGBM/src/treelearner/split_info.hpp

Line 56 in 5cd95a5

return 2 * sizeof(int) + sizeof(uint32_t) + sizeof(bool) + sizeof(double) * 7 + sizeof(data_size_t) * 2 + max_cat_threshold * sizeof(uint32_t) + sizeof(int8_t);

This code is used for computing the buffer size of the communicating the split info the in distributed training. But lost the two most recently added parameters(right_sum_gradient_and_hessian, left_sum_gradient_and_hessian) size.
When use parallel_tree_learner method with number of categories of one feature larger than 28 (default max_cat_to_onehot(32)-2*2), it will resut in an Segmentation fault.

This code must be,

  inline static int Size(int max_cat_threshold) {
    return 2 * sizeof(int) + sizeof(uint32_t) + sizeof(bool) + sizeof(double) * 7 + sizeof(data_size_t) * 2 + max_cat_threshold * sizeof(uint32_t) + sizeof(int8_t) + sizeof(int64_t)*2;
  }