@thi.ng/adjacency/floyd-warshall.d.ts

Sparse & bitwise adjacency matrices, lists and selected traversal algorithms for directed & undirected graphs

import type { Maybe } from "@thi.ng/api";
import type { CostFn, IGraph } from "./api.js";
/**
 * Implementation of the Floyd-Warshall algorithm for finding _all_ shortest
 * paths in a directed graph, optionally with positive or negative edge weights.
 * A single execution of the algorithm will find the lengths (summed weights) of
 * shortest paths between all pairs of vertices.
 *
 * @remarks
 * The default cost function is topological distance (i.e. every edge has a
 * length/cost of 1).
 *
 * Paths & accumulated distances can be queried via {@link FloydWarshall.path}
 * and {@link FloydWarshall.distance}.
 *
 * This algorithm is quite memory hungry and requires `|V| * |V| * 8 bytes`,
 * i.e. ~8MB for a graph with 1000 nodes. If possible, use {@link BFS} to
 * perform individual shortest-path queries (rather than this global approach).
 *
 * References:
 *
 * - https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm
 */
export declare class FloydWarshall {
    dist: Float32Array;
    next: Int32Array;
    numV: number;
    /**
     * Instantiates and pre-computes all shortest paths in given `graph`. See
     * class comments for details.
     *
     * @param graph
     * @param cost
     */
    constructor(graph: IGraph<number>, cost?: CostFn);
    /**
     * Returns shortest distance between vertices `a` and `b`, or `undefined` if
     * no connecting path exists. Throws an error if either `a` or `b` are out
     * of bounds.
     *
     * @param a
     * @param b
     */
    distance(a: number, b: number): Maybe<number>;
    /**
     * Returns iterator of vertex IDs of path between `a` and `b` (if any).
     * Throws an error if either `a` or `b` are out of bounds.
     *
     * @param a
     * @param b
     */
    path(a: number, b: number): Generator<number, void, unknown>;
    protected ensureIndex(id: number): void;
    protected ensurePair(a: number, b: number): void;
}
/**
 * Factory function for {@link FloydWarshall}.
 *
 * @param graph
 * @param cost
 */
export declare const floydWarshall: (graph: IGraph<number>, cost?: CostFn) => FloydWarshall;
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