Struct DL85Builder 

pub struct DL85Builder<C, D, E, H>
where
    C: Caching + ?Sized,
    D: OptimalDepth2Tree + ?Sized,
    E: ErrorWrapper + ?Sized,
    H: Heuristic + ?Sized,
{ /* private fields */ }

Builder for DL85.

A cache, a depth-2 solver, an error function and a heuristic are required. The pure-node, lower-bound and already-solved rules are always included; depth, support and time limits add their own rules.

use dtrees_rs::algorithms::common::errors::NativeError;
use dtrees_rs::algorithms::common::heuristics::NoHeuristic;
use dtrees_rs::algorithms::optimal::depth2::ErrorMinimizer;
use dtrees_rs::algorithms::optimal::dl85::DL85Builder;
use dtrees_rs::caching::Trie;

let error_fn = Box::<NativeError>::default();
let dl85 = DL85Builder::default()
    .max_depth(3)
    .min_support(5)
    .max_time(60.0)
    .cache(Box::<Trie>::default())
    .heuristic(Box::<NoHeuristic>::default())
    .depth2_search(Box::new(ErrorMinimizer::new(error_fn.clone())))
    .error_function(error_fn)
    .build();
assert!(dl85.is_ok());

Implementations

impl<C, D, E, H> DL85Builder<C, D, E, H>

where C: Caching + ?Sized, D: OptimalDepth2Tree + ?Sized, E: ErrorWrapper + ?Sized, H: Heuristic + ?Sized,

pub fn new() -> Self

A builder with the default rules and no limits.

pub fn min_support(self, value: usize) -> Self

Minimum number of instances in each leaf.

pub fn max_depth(self, value: usize) -> Self

Maximum depth of the tree.

pub fn max_error(self, value: f64) -> Self

Only trees with a lower error are accepted.

pub fn max_time(self, value: f64) -> Self

Time limit in seconds for the whole search.

pub fn default_rules(self) -> Self

Adds the rules every search needs: already-solved nodes, pure nodes and the lower bound. Called by Self::new.

pub fn depth2_search(self, search: Box<D>) -> Self

The solver used for depth-2 subtrees.

pub fn add_node_rule(self, rule: Box<dyn Rule>) -> Self

Adds a rule evaluated on entering each node.

pub fn add_node_rules(self, rules: Vec<Box<dyn Rule>>) -> Self

Adds several node rules.

pub fn add_search_rule(self, rule: Box<dyn Rule>) -> Self

Adds a rule evaluated before branching on each candidate feature, such as DiscrepancyRule or TopkRule.

pub fn add_search_rules(self, rules: Vec<Box<dyn Rule>>) -> Self

Adds several search rules.

pub fn always_sort(self, value: bool) -> Self

Sort the features by the heuristic at every node, not only at the root.

pub fn specialization(self, value: OptimalDepth2Policy) -> Self

Whether to use the depth-2 solver.

pub fn lower_bound_strategy(self, value: LowerBoundPolicy) -> Self

Whether to use the similarity lower bound.

pub fn branching_strategy(self, value: BranchingPolicy) -> Self

Which branch of a feature is searched first.

pub fn node_exposed_data(self, value: NodeDataType) -> Self

What the error function receives: class counts or instance ids.

pub fn cache(self, value: Box<C>) -> Self

The cache of subproblems.

pub fn error_function(self, value: Box<E>) -> Self

The error of a leaf.

pub fn heuristic(self, value: Box<H>) -> Self

The heuristic used to order features.

pub fn build(self) -> Result<DL85<C, D, E, H>, String>

Builds the search, or says which required part is missing.

Trait Implementations

impl<C, D, E, H> Default for DL85Builder<C, D, E, H>

where C: Caching + ?Sized, D: OptimalDepth2Tree + ?Sized, E: ErrorWrapper + ?Sized, H: Heuristic + ?Sized,

fn default() -> Self

Returns the “default value” for a type.