Enum HistNode 

pub enum HistNode<F> {
    Split {
        feature: usize,
        threshold_bin: u16,
        nan_goes_left: bool,
        left: usize,
        right: usize,
        gain: F,
        n_samples: usize,
    },
    Leaf {
        value: F,
        n_samples: usize,
    },
}

A node in a histogram-based gradient boosting tree.

Unlike crate::decision_tree::Node, thresholds are stored as bin indices rather than raw feature values. Prediction at a split checks whether the sample’s bin index for the feature is <= threshold_bin.

Variants

Split

An internal split node.

Fields

feature: usize

Feature index used for the split.

threshold_bin: u16

Bin index threshold; samples with bin[feature] <= threshold_bin go left.

nan_goes_left: bool

Whether NaN values should go left (true) or right (false).

left: usize

Index of the left child node in the flat vec.

right: usize

Index of the right child node in the flat vec.

gain: F

Weighted gain from this split (for feature importance).

n_samples: usize

Number of samples that reached this node during training.

Leaf

A leaf node that stores a prediction value.

Fields

value: F

Predicted value (raw leaf output, e.g. gradient step).

n_samples: usize

Number of samples that reached this node during training.

Trait Implementations

impl<F: Clone> Clone for HistNode<F>

fn clone(&self) -> HistNode<F>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<F: Debug> Debug for HistNode<F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, F> Deserialize<'de> for HistNode<F>

where F: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<F> Serialize for HistNode<F>

where F: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.