What is FGraph

The FGraph is an adaptation of a functional graph. In programming, a functional graph typically refers to a data structure or representation used to model and analyze the flow of data or the dependencies between functions in a functional programming paradigm. Functional programming emphasizes the use of pure functions and avoids mutable state, making functional graphs particularly useful for understanding and optimizing the execution of functional programs. It is compromised of a Dictionary, containing the nodeIndex as Key and the so called FContext as Value. The structure is visualised here:

Quickstart

Creating an empty graph and filling it with single elements

Begin by creating an empty graph,meaning a data structure with no nodes or edges. Then populate the graph with single elements, individual nodes are added one by one, and edges can be introduced to establish connections between them.

open Graphoscope
open FGraph

let graphToFill =

    FGraph.empty
    |> FGraph.addNode 1 "1"
    |> FGraph.addNode 2 "2"
    |> FGraph.addEdge 1 2 1.

"You have created a graph with 2 nodes and 1 edges"

Working with Graphs

Creating a Graph using FGraph

Creating an empty graph and add collections of elements

Another way of creating a graph is by filling it with collections of nodes and edges as seen below:

let graphToFill' =
    
    let nodes = List.init 100 (fun x -> x,$"{x}")

    let edges = List.init 45 (fun x -> x,x*2,1.)

    FGraph.empty
    |> FGraph.addNodes nodes
    |> FGraph.addEdges edges

"You have created a graph with 100 nodes and 45 edges"

Removing Nodes and Edges

To remove Nodes or Edges you can just use the remove functions provided:

let graphWithRemovedElements =
    graphToFill'
    |> FGraph.removeEdge 1 2
    |> FGraph.removeNode 0

"You have reduced the graph to 99 nodes and 43 edges"

From Data

Import a graph

This directed network contains observed grooming episodes between free ranging rhesus macaques (Macaca mulatta) in Cayo Santiago during a two month period in 1963. Cayo Santiago is an island off the coast of Puerto Rico, also known as Isla de los monos (Island of the monkeys). A node represents a monkey and a directed edge A → B denotes that the rhesus macaque A groomed rhesus macaque B. The integer edge weights indicate how often this behaviour was observed.

open Graphoscope

open FSharpAux.IO
open FSharpAux.IO.SchemaReader.Attribute

First we model the input domain as a reccord type and read a sequence of MonkeyEdges

type MonkeyEdge = {
    [<Field(0)>] Source  : int
    [<Field(1)>] Target  : int
    [<Field(2)>] Groomed : int
}

let monkeyEdges =
    Seq.fromFileWithCsvSchema<MonkeyEdge>("D:/Source/Graphoscope/tests/Graphoscope.Tests/ReferenceGraphs/out.moreno_rhesus_rhesus.txt",' ',false,skipLines=2 )

Convert a MonkeyEdge record to a sequence of graph elements (sourceKey * sourceData * targetKey * targetData * edgeData)

let monkeyGraph =
    monkeyEdges
    |> Seq.map (fun mke ->
        mke.Source, sprintf "Monkey_%i" mke.Source,mke.Target,sprintf "Monkey_%i" mke.Target,float mke.Groomed)
    |> FGraph.ofSeq

let's use Cytoscape.NET for visualization:

open Cytoscape.NET
let vizGraph =
    CyGraph.initEmpty ()
    |> CyGraph.withElements [
            for (sk,s,tk,t,el) in (FGraph.toSeq monkeyGraph) do
                let sk, tk = (string sk), (string tk)
                yield Elements.node sk [ CyParam.label s ]
                yield Elements.node tk [ CyParam.label t ]
                yield Elements.edge  (sprintf "%s_%s" sk tk) sk tk [ CyParam.label el ]
        ]
    |> CyGraph.withStyle "node"     
        [
            CyParam.content =. CyParam.label
            CyParam.color "#A00975"
        ]

No value returned by any evaluator