graph

Documentation

Overview

*

• Package graph implements a Graph that can be either a King's graph
• or a Grid graph. It can generate a graph from a given image.

Index

• type Edge
  • func (e *Edge) U() int
  • func (e *Edge) V() int
  • func (e *Edge) Weight() float64
• type EdgeList
  • func (edges EdgeList) Len() int
  • func (edges EdgeList) Less(i, j int) bool
  • func (edges EdgeList) Swap(i, j int)
• type Graph
  • func FromImage(img image.Image, weight WeightFn, graphType GraphType) *Graph
  • func New(width, height int, graphType GraphType) *Graph
  • func (g *Graph) Edges() EdgeList
  • func (g *Graph) Height() int
  • func (g *Graph) Neighbors(v int) <-chan int
  • func (g *Graph) TotalEdges() int
  • func (g *Graph) TotalVertices() int
  • func (g *Graph) Weight(u, v int) float64
  • func (g *Graph) Width() int
• type GraphType
• type Pixel
• type WeightFn

Types

type Edge

type Edge struct {
	// contains filtered or unexported fields
}

*

• Represents a graph edge. It contains the ids of the two vertices
• that it connects and the weight of the edge between them

func (*Edge) U

func (e *Edge) U() int

*

• Return the id of one of the vertices that Edge e connects

func (*Edge) V

func (e *Edge) V() int

*

• Return the id of one of the vertices that Edge e connects

func (*Edge) Weight

func (e *Edge) Weight() float64

*

• Return the weight of Edge e

type EdgeList

type EdgeList []Edge

*

• Used to store all the edges that the graph contains.
• It can be used with sort.Sort

func (EdgeList) Len

func (edges EdgeList) Len() int

*

• Return the number of edges that the EdgeList edges stores

func (EdgeList) Less

func (edges EdgeList) Less(i, j int) bool

*

• Returns true if the weight of the edge i is less than the weight
• of the edge j

func (EdgeList) Swap

func (edges EdgeList) Swap(i, j int)

*

• In place swap of two edges i and j in the edge list

type Graph

type Graph struct {
	// contains filtered or unexported fields
}

*

• Graph datatype. Contains a list of edges, the graph width and height and
• if it's a King's graph or a Grid graph

func FromImage

func FromImage(img image.Image, weight WeightFn, graphType GraphType) *Graph

*

• Returns a new graph that represents the image img. The graph will be either
• a King's grph or a Grid graph. It will compute the edge weights using the
• provided function weight.

func New

func New(width, height int, graphType GraphType) *Graph

*

• Returns a new width x height King's or Grid graph. It assigns a weight of Infinity
• to all edges

func (*Graph) Edges

func (g *Graph) Edges() EdgeList

*

• Returns all the edges that the graph has

func (*Graph) Height

func (g *Graph) Height() int

*

• Returns the height of a graph

func (*Graph) Neighbors

func (g *Graph) Neighbors(v int) <-chan int

*

• Return the ids of the vertices to which v is adjacent

func (*Graph) TotalEdges

func (g *Graph) TotalEdges() int

*

• Returns the total number of edges that the graph has

func (*Graph) TotalVertices

func (g *Graph) TotalVertices() int

*

• Returns the total number of vertices that the graph has

func (*Graph) Weight

func (g *Graph) Weight(u, v int) float64

func (*Graph) Width

func (g *Graph) Width() int

*

• Returns the width of a graph

type GraphType

type GraphType int

*

• Used to recongise which type of graph to generate

const (
	GRIDGRAPH  GraphType = iota
	KINGSGRAPH GraphType = iota
)

type Pixel

type Pixel struct {
	X, Y  int
	Color color.Color
}

*

• Used to compute the weight of an edge when generating a graph
• from an image

type WeightFn

type WeightFn func(Pixel, Pixel) float64

*

• Type of the functions that are used to compute the weight of
• an edge when generating a graph from an image