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https://github.com/nullobject/purescript-digraph
A directed graph library for PureScript.
https://github.com/nullobject/purescript-digraph
graph purescript
Last synced: 6 days ago
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A directed graph library for PureScript.
- Host: GitHub
- URL: https://github.com/nullobject/purescript-digraph
- Owner: nullobject
- License: mit
- Created: 2016-03-26T22:29:44.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2019-01-12T22:59:01.000Z (almost 6 years ago)
- Last Synced: 2024-10-21T18:28:57.089Z (22 days ago)
- Topics: graph, purescript
- Language: PureScript
- Size: 52.7 KB
- Stars: 11
- Watchers: 3
- Forks: 6
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# purescript-digraph
[](https://travis-ci.com/nullobject/purescript-digraph)
A directed graph library for PureScript.
## Examples
### Adjacency list
The directed graph pictured above can be represented with an `AdjacencyList`.
An adjacency list is a list of tuples that contain a vertex and a list of edges
to its adjacent vertices. A `Graph` can be constructed from an `AdjacencyList`.
```haskell
let edges = fromFoldable $
[ Tuple 'A' (fromFoldable [Tuple 'B' 1, Tuple 'C' 2])
, Tuple 'B' (fromFoldable [Tuple 'A' 1, Tuple 'D' 3])
, Tuple 'C' (fromFoldable [Tuple 'A' 2, Tuple 'D' 4])
, Tuple 'D' (fromFoldable [Tuple 'B' 3, Tuple 'C' 4])
, Tuple 'E' (fromFoldable [Tuple 'F' 1])
, Tuple 'F' (fromFoldable [Tuple 'E' 1])
, Tuple 'G' (fromFoldable [])
]
let graph = fromAdjacencyList edges
```
### Size
The `size` function returns the number of vertices in a graph.
```haskell
size graph
-- 7
```
### Vertices
The `vertices` function returns a list of the vertices in a graph.
```haskell
vertices graph
-- ['A', 'B', 'C', 'D', 'E', 'F', 'G']
```
### Edges
The `isAdjacent` function returns true if two vertices are connected by an edge.
```haskell
isAdjacent 'A' 'B' graph
-- true
```
The `weight` function returns the weight of the edge between two vertices.
```haskell
weight 'A' 'B' graph
-- Just 1
```
The `adjacent` function returns all vertices connected to a vertex by an edge.
The `adjacent'` function will also include the weight of the edges.
```haskell
adjacent 'A' graph
-- ['B', 'C']
adjacent' 'A' graph
-- [Tuple 'B' 1, Tuple 'C' 2]
```
### Shortest path
The `shortestPath` function calculates the shortest path between two vertices
using [Dijkstra'a
algorithm](https://en.wikipedia.org/wiki/Dijkstra's_algorithm).
```haskell
shortestPath 'A' 'D' graph
-- ['A', 'B', 'D']
```
### Connected components
The `connectedComponents` function calculates a list of connected components in a graph.
A [connected
component](https://en.wikipedia.org/wiki/Connected_component_(graph_theory)) is
a maximal subgraph in which any two vertices are connected to each other by a
path.
```haskell
connectedComponents graph
-- [Graph, Graph, Graph]
```
### Building
An empty graph can be constructed and updated.
```haskell
(insertEdge 'A' 'B' 1 <<< insertVertex 'A' <<< insertVertex 'B') empty
-- Graph
```
## API
[Data.Graph](https://pursuit.purescript.org/packages/purescript-digraph)