Trait RelationIndex 

pub trait RelationIndex: TopologyBase {
    // Required methods
    fn relation_bound(&self) -> usize;
    fn relation_index(&self, relation: Self::RelationId) -> usize;
}

Dense relation-index capability for topology views.

This capability maps visible relation IDs to compact array indexes usable by algorithms that need per-relation scratch storage. The index is a property of the view, not the ID type itself.

relation_bound is an allocation bound, not necessarily the exact visible relation count. Immutable compact layouts usually have relation_bound() == relation_count(). Mutable layouts may expose a larger bound.

Implementations must ensure every valid visible relation maps to an index less than relation_bound, distinct visible relations map to distinct indexes, and indexes remain stable for the lifetime of the view operation using them.

Performance

Methods should be O(1) unless an implementation documents a weaker contract.

Required Methods

fn relation_bound(&self) -> usize

Returns the exclusive upper bound for relation indexes in this view.

Performance

Expected O(1) unless the implementation documents otherwise.

fn relation_index(&self, relation: Self::RelationId) -> usize

Returns the dense index for relation in this view.

Performance

Expected O(1) unless the implementation documents otherwise.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors