xgbin

type GBLinearModel struct {
	Param   GBLinearModelParam
	Weights []float32
}

type GBLinearModelParam struct {
	// number of feature dimension
	NumFeature uint32
	// number of output group
	NumOutputGroup int32
	// reserved field
	Reserved [32]int32
}

type GBTreeModel struct {
	Param GBTreeModelParam
	Trees []*TreeModel
	// some information indicator of the tree, reserved
	TreeInfo []int32
}

type GBTreeModelParam struct {
	// number of trees
	NumTrees int32
	// number of roots
	NumRoots int32
	// number of features to be used by trees
	NumFeature int32
	// pad this space, for backward compatibility reason
	Pad32bit int32
	// deprecated padding space.
	NumPbufferDeprecated int64
	// how many output group a single instance can produce
	// this affects the behavior of number of output we have:
	// suppose we have n instance and k group, output will be k * n
	NumOutputGroup int32
	// size of leaf vector needed in tree
	SizeLeafVector int32
	// reserved parameters
	Reserved [32]int32
}

type LearnerModelParam struct {
	// global bias
	BaseScore float32
	// number of features
	NumFeatures uint32
	// number of classes, if it is multi-class classification
	NumClass int32
	// Model contain additional properties
	ContainExtraAttrs int32
	// Model contain eval metrics
	ContainEvalMetrics int32
	// reserved field
	Reserved [29]int32
}

type ModelHeader struct {
	Param   LearnerModelParam
	NameObj string
	NameGbm string
}

type Node struct {
	// pointer to parent, highest bit is used to
	// indicate whether it's a left child or not
	Parent int32
	// pointer to left, right
	// NOTE: CLeft == -1 means leaf node
	CLeft  int32
	CRight int32
	// split feature index, left split or right split depends on the highest bit
	SIndex uint32
	// extra info
	// union Info{
	//   bst_float leaf_value;
	//   TSplitCond split_cond;
	// };
	Info float32
}

type RTreeNodeStat struct {
	// loss change caused by current split
	LossChg float32
	// sum of hessian values, used to measure coverage of data
	SumHess float32
	// weight of current node
	BaseWeight float32
	// number of child that is leaf node known up to now
	LeafChildCnt int32
}

type TreeModel struct {
	Nodes []Node
	Stats []RTreeNodeStat
	// // leaf vector, that is used to store additional information
	// LeafVector []float32
	Param TreeParam
}

type TreeParam struct {
	// number of start root
	NumRoots int32
	// total number of nodes
	NumNodes int32
	// number of deleted nodes
	NumDeleted int32
	// maximum depth, this is a statistics of the tree
	MaxDepth int32
	// number of features used for tree construction
	NumFeature int32
	// leaf vector size, used for vector tree
	// used to store more than one dimensional information in tree
	SizeLeafVector int32
	// reserved part, make sure alignment works for 64bit
	Reserved [31]int32
}