package graph6

import "gonum.org/v1/gonum/graph/encoding/graph6"

Package graph6 implements graphs specified by graph6 strings.

Index ¶

• func IsValid(g Graph) bool
• type Graph
• func Encode(g graph.Graph) Graph
• func (g Graph) Edge(uid, vid int64) graph.Edge
• func (g Graph) EdgeBetween(xid, yid int64) graph.Edge
• func (g Graph) From(id int64) graph.Nodes
• func (g Graph) GoString() string
• func (g Graph) HasEdgeBetween(xid, yid int64) bool
• func (g Graph) Node(id int64) graph.Node
• func (g Graph) Nodes() graph.Nodes

Examples ¶

• Graph

Functions ¶

func IsValid ¶

func IsValid(g Graph) bool

IsValid returns whether the graph is a valid graph6 encoding. An invalid Graph behaves as the null graph.

Types ¶

type Graph ¶

type Graph string

Graph is a graph6-represented undirected graph.

See https://users.cecs.anu.edu.au/~bdm/data/formats.txt for details and https://hog.grinvin.org/ for a source of interesting graphs in graph6 format.

package main

import (
	"fmt"

	"gonum.org/v1/gonum/graph"
	"gonum.org/v1/gonum/graph/encoding/graph6"
)

func main() {
	// Construct a graph from HOG graph 32194.
	// https://hog.grinvin.org/ViewGraphInfo.action?id=32194
	g := graph6.Graph("H@BQPS^")

	// Get the nodes of the graph and print
	// an adjacency list.
	nodes := g.Nodes()
	fmt.Printf("Number of nodes: %d\n", nodes.Len())
	fmt.Println("Adjacency:")
	for nodes.Next() {
		fmt.Printf("\t%d: %d\n", nodes.Node().ID(), graph.NodesOf(g.From(nodes.Node().ID())))
	}

}

Number of nodes: 9
Adjacency:
	0: [5]
	1: [5 6]
	2: [3 7]
	3: [2 5 8]
	4: [6 7 8]
	5: [0 1 3 8]
	6: [1 4 7 8]
	7: [2 4 6 8]
	8: [3 4 5 6 7]

func Encode ¶

func Encode(g graph.Graph) Graph

Encode returns a graph6 encoding of the topology of the given graph using a lexical ordering of the nodes by ID to map them to [0, n).

func (Graph) Edge ¶

func (g Graph) Edge(uid, vid int64) graph.Edge

Edge returns the edge from u to v, with IDs uid and vid, if such an edge exists and nil otherwise. The node v must be directly reachable from u as defined by the From method.

func (Graph) EdgeBetween ¶

func (g Graph) EdgeBetween(xid, yid int64) graph.Edge

EdgeBetween returns the edge between nodes x and y with IDs xid and yid.

func (Graph) From ¶

func (g Graph) From(id int64) graph.Nodes

From returns all nodes that can be reached directly from the node with the given ID.

func (Graph) GoString ¶

func (g Graph) GoString() string

func (Graph) HasEdgeBetween ¶

func (g Graph) HasEdgeBetween(xid, yid int64) bool

HasEdgeBetween returns whether an edge exists between nodes with IDs xid and yid without considering direction.

func (Graph) Node ¶

func (g Graph) Node(id int64) graph.Node

Node returns the node with the given ID if it exists in the graph, and nil otherwise.

func (Graph) Nodes ¶

func (g Graph) Nodes() graph.Nodes

Nodes returns all the nodes in the graph.

Source Files ¶

graph6.go