Enum Node 

pub enum Node<F> {
    Split {
        feature: usize,
        threshold: F,
        left: usize,
        right: usize,
        impurity_decrease: F,
        n_samples: usize,
    },
    Leaf {
        value: F,
        class_distribution: Option<Vec<F>>,
        n_samples: usize,
    },
}

A single node in the decision tree, stored in a flat Vec for cache efficiency.

Internal nodes hold a split (feature index + threshold), while leaf nodes store a prediction value and optional class distribution (for classifiers).

Variants

Split

An internal split node.

Fields

feature: usize

Feature index used for the split.

threshold: F

Threshold value; samples with x[feature] <= threshold go left.

left: usize

Index of the left child node in the flat vec.

right: usize

Index of the right child node in the flat vec.

impurity_decrease: F

Weighted impurity decrease 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.

Fields

value: F

Predicted value: class label (as F) for classifiers, mean for regressors.

class_distribution: Option<Vec<F>>

Class distribution (proportion of each class). Only used by classifiers.

n_samples: usize

Number of samples that reached this node during training.

Trait Implementations

impl<F: Clone> Clone for Node<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for Node<F>

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

Formats the value using the given formatter.

impl<'de, F> Deserialize<'de> for Node<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 Node<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.