Struct EGraph 

pub struct EGraph { /* private fields */ }

An equivalence graph for layout expressions.

Stores expressions and their equivalence classes. Supports adding expressions, merging equivalence classes, and applying rewrite rules to discover equivalent layouts.

Implementations

impl EGraph

pub fn new() -> Self

Create a new empty e-graph.

pub fn add(&mut self, expr: Expr) -> Id

Add an expression to the e-graph, returning its equivalence class id.

If the expression already exists (structurally identical after canonicalization), returns the existing id.

pub fn equiv(&self, a: Id, b: Id) -> bool

Check if two ids are in the same equivalence class.

pub fn merge(&mut self, a: Id, b: Id) -> Id

Merge two equivalence classes, returning the new canonical id.

pub fn find(&self, id: Id) -> Id

Find the canonical representative of an equivalence class.

pub fn class_count(&self) -> usize

Number of equivalence classes.

pub fn node_count(&self) -> usize

Total number of expression nodes.

pub fn last_apply_count(&self) -> usize

Number of rule applications in the last apply_rules call.

pub fn apply_rules(&mut self) -> usize

Apply rewrite rules until saturation (no new equalities discovered) or the iteration budget is exhausted.

Returns the total number of rule applications.

pub fn apply_rules_with_budget(&mut self, max_iterations: usize) -> usize

Apply rewrite rules with an explicit iteration budget.

pub fn extract(&self, id: Id) -> Expr

Extract the best expression from an equivalence class.

Uses a simple cost model: prefer fewer nodes and simpler operations.

impl EGraph

pub fn saturate(&mut self, config: &SaturationConfig) -> SaturationResult

Run equality saturation with explicit resource bounds.

Returns a SaturationResult indicating completion status. If the node budget, time limit, or memory limit is hit, the current state is preserved and the caller can still extract results.

pub fn memory_usage(&self) -> usize

Estimated memory usage in bytes.

Trait Implementations

impl Debug for EGraph

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

Formats the value using the given formatter.

impl Default for EGraph

fn default() -> Self

Returns the “default value” for a type.