GBDT:Gradient Boosting Decision Tree implemented by golang.
Concurrency:Implementing local cocurrent with goroutine when building single tree at each iteration.
Support missing feature value.Every node in the tree has a child named "UNKNOWN VALUE".So every tree is the ternary tree
1 1 0:1.1446 1:2 2:35 3:0 4:206.0 ....
weight label featureid:feature_value....
#Parameter All gbdt parameter define in config.go.
Number_of_feature:Feature dimensions.eg:In example/train.data,there are 17 different features.
Max_depth:The maximal depth of the tree.
Tree_count:Tree count ,namely iteration numbers.
Feature_sampling_ratio:Feature sample ratio for build tree.
Data_sampling_ratio:Data sample ration for build tree.
Min_leaf_size:Minimal number of samples in leaf.
Losstype :Loss function type,eg least square,log likehood
Debug :Print some debug info.