Struct Cover 

pub struct Cover {
    pub num_attributes: usize,
    pub num_labels: usize,
    pub num_samples: usize,
    /* private fields */
}

A binary dataset and the set of instances reaching the current node.

Features and classes are stored as bitsets over the instances. Branching on an item intersects the current set with a feature’s bitset (or its complement), and backtracking restores the previous set in constant time thanks to a reversible sparse bitset.

An item encodes a feature and a branch: 2 * feature is the branch where the feature is 0 (left) and 2 * feature + 1 the branch where it is 1 (right). See crate::globals.

Fields

num_attributes: usize

Number of binary features.

num_labels: usize

Number of classes.

num_samples: usize

Number of instances in the dataset.

Implementations

impl Cover

pub fn new( attributes: Vec<Bitset>, labels: Vec<Bitset>, num_samples: usize, ) -> Self

A cover over all instances, from one bitset per feature (instances where it is 1) and one per class.

pub fn count(&self) -> usize

Number of instances in the current node.

pub fn labels_count(&self) -> Vec<usize>

Number of instances of each class in the current node.

pub fn labels_count_with_buffer(&self, buffer: &mut Vec<usize>)

Self::labels_count writing into buffer.

pub fn branch_on(&mut self, item: usize) -> usize

Moves to the child reached by item and returns its number of instances.

pub fn count_if_branch_on(&self, item: usize) -> usize

Number of instances the child reached by item would have.

pub fn backtrack(&mut self)

Returns to the parent of the current node.

Panics

At the root.

pub fn to_vec(&self) -> Vec<usize>

Ids of the instances in the current node.

pub fn shallow_cover(&self) -> ShallowBitset

A plain copy of the current set of instances.

pub fn sparse(&self) -> &SparseBitset

The reversible set of instances.

pub fn path(&self) -> &[usize]

Items branched on from the root to the current node.