Struct forust_ml::splitter::MissingImputerSplitter

pub struct MissingImputerSplitter {
    pub l2: f32,
    pub gamma: f32,
    pub min_leaf_weight: f32,
    pub learning_rate: f32,
    pub allow_missing_splits: bool,
    pub constraints_map: ConstraintMap,
}

Missing imputer splitter Splitter that imputes missing values, by sending them down either the right or left branch, depending on which results in a higher increase in gain.

Fields

l2: f32

gamma: f32

min_leaf_weight: f32

learning_rate: f32

allow_missing_splits: bool

constraints_map: ConstraintMap

Implementations

impl MissingImputerSplitter

pub fn new( l2: f32, gamma: f32, min_leaf_weight: f32, learning_rate: f32, allow_missing_splits: bool, constraints_map: ConstraintMap ) -> Self

Generate a new missing imputer splitter object.

Trait Implementations

impl Splitter for MissingImputerSplitter

fn evaluate_split( &self, left_gradient: f32, left_hessian: f32, right_gradient: f32, right_hessian: f32, missing_gradient: f32, missing_hessian: f32, lower_bound: f32, upper_bound: f32, constraint: Option<&Constraint> ) -> Option<(NodeInfo, NodeInfo, MissingInfo)>

Evaluate a split, returning the node info for the left, and right splits, as well as the node info the missing data of a feature.

fn handle_split_info( &self, split_info: SplitInfo, n_nodes: &usize, node: &mut SplittableNode, index: &mut [usize], data: &Matrix<'_, u16>, cuts: &JaggedMatrix<f64>, grad: &[f32], hess: &[f32], parallel: bool ) -> Vec<SplittableNode>

Handle the split info, creating the children nodes, this function will return a vector of new splitable nodes, that can be added to the growable stack, and further split, or converted to leaf nodes.

fn get_constraint(&self, feature: &usize) -> Option<&Constraint>

fn get_gamma(&self) -> f32

fn get_l2(&self) -> f32

fn best_split(&self, node: &SplittableNode) -> Option<SplitInfo>

Find the best possible split, considering all feature histograms. If we wanted to add Column sampling, this is probably where we would need to do it, otherwise, it would be at the tree level.

fn best_feature_split( &self, node: &SplittableNode, feature: usize ) -> Option<SplitInfo>

fn split_node( &self, n_nodes: &usize, node: &mut SplittableNode, index: &mut [usize], data: &Matrix<'_, u16>, cuts: &JaggedMatrix<f64>, grad: &[f32], hess: &[f32], parallel: bool ) -> Vec<SplittableNode>

Split the node, if we cant find a best split, we will need to return an empty vector, this node is a leaf.