ComradeVanti / FDijkstra

An F# implementation of Dijkstras algorithm

FDijkstra

An F# implementation of Dijkstras algorithm

⚠️ Development is paused ⚠️
No new features will be added or bugs fixed unless requested through an issue.
If you wish to fork this repository and continue the work, you are very welcome to do so.

The implementation works with all sorts of graphs as long as it fulfills the following requirements:

• It has vertices
• It can find vertices connected to a specific vertex
• It can measure the distance between two connected vertices

The general syntax for using the algorithm is

ComradeVanti.FDijkstra.Dijkstra.solve start goal vertices neighbors distanceBetween

with

• start is the vertex where from which to begin the search
• goal is the vertex where to which a path should be searched
• vertices are all the vertices in the graph
• neighbors is a function which finds adjacent vertices to a vertex
• distanceBetween is a function which measures distance between two connected vertices

An example with actual values could be:

let vertices = [ 0; 1; 2; 3 ]

// Tuples are of the form ((vertex1, vertex2), distance)
let edges =
    [ ((0, 1), 2)
      ((1, 2), 4)
      ((2, 3), 3)
      ((1, 3), 7)
      ((0, 2), 4) ]

let neighbors v =
    [ edges
      |> List.filter (fst >> fst >> (=) v)
      |> List.map (fst >> snd)
      edges
      |> List.filter (fst >> snd >> (=) v)
      |> List.map (fst >> fst) ]
    |> List.concat

let distance v1 v2 =
    edges
    |> List.tryFind (fst >> (fun e -> e = (v1, v2) || e = (v2, v1)))
    |> Option.map snd
    |> Option.defaultValue 1000

solve 0 3 vertices neighbors distance