Dynamic graph algorithms.

A library for dynamic graph algorithms, and in particular dynamic connectivity.

dynamic-graphs

Summary

A Haskell library for dealing with the dynamic connectivity problem. Consider an undirected graph, where edges may be added and removed. This library allows you to answer the question "are the nodes X and Y connected" at any point in time.

This blogpost has some more information about this library: https://jaspervdj.be/posts/2019-01-11-dynamic-graphs.html.

Installation

dynamic-graphs is available on hackage. You can install it using Stack, Cabal, Nix, or whichever tool you prefer.

Example

import qualified Data.Graph.Dynamic.Levels as GD
import qualified Data.Tree as T

main :: IO ()
main = do
    graph <- GD.empty'
    mapM_ (GD.insert_ graph) ["Akanu", "Kanoa", "Kekoa", "Kaiwi", "Onakea"]
    GD.link_ graph "Akanu" "Kanoa"
    GD.link_ graph "Akanu" "Kaiwi"
    GD.link_ graph "Akanu" "Onakea"
    GD.link_ graph "Kaiwi" "Onakea"
    GD.link_ graph "Onakea" "Kanoa"
    GD.link_ graph "Kanoa" "Kekoa"

    GD.connected graph "Kaiwi" "Kekoa" >>= print
    GD.cut_ graph "Kaiwi" "Akanu"
    GD.cut_ graph "Onakea" "Akanu"
    GD.cut_ graph "Onakea" "Kanoa"
    GD.connected graph "Kaiwi" "Kekoa" >>= print
    GD.link_ graph "Akanu" "Kaiwi"
    GD.connected graph "Kaiwi" "Kekoa" >>= print