Struct Graph

pub struct Graph {
    pub vertices: HashMap<String, Vertex>,
    pub edges: HashMap<(String, String), Edge>,
    pub edge_type: EdgeType,
}

This is the basic graph structure. Graph consists of vertices, edges and edge_type

Vertices:

Vertices - Hashmap of type String, Vertex. Vertex has a label and a value

Example: A vertex with label A and value 10 will look like this

 self.vertices.insert(
    String::from("A");
    Vertex {
        label: String::from("A"),
        value: 10,
    },
);

The structure of the vertex

pub struct Vertex<T> {
    pub label: VLT,
    pub value: T,
}

Edges:

Edges - Hashmap of type (VLT, VLT), Edge.

(VLT, VLT) are two end points of the edge.

Edge has weight and edge type

Example:

HashMap - Key: (String::from("A"), String::from("B")) | Value: Edge

Edge Looks like this:

pub struct Edge {
    pub endpoints: (VLT, VLT),
    pub weight: GNumber,
    pub edge_type: EdgeType,
}

Edge Type

edge_type: EdgeType - Directed or Undirected

Fields

vertices: HashMap<String, Vertex>

edges: HashMap<(String, String), Edge>

edge_type: EdgeType

Implementations

impl Graph

pub fn new(directed: bool) -> Graph

Creates a new Graph

Parameters:

directed - type boolean

directed = true if we want a directed graph

directed = false if we want an undirected graph

Return value

This function returns Graph - directed or undirected based on the parameter passed (Graph)

Example

Basic Usage:

1. Undirected graph:

let mut g: graphs::Graph = graphs::Graph::new(false);

2. Directed graph:

let mut g: graphs::Graph = graphs::Graph::new(true);

pub fn print(&self)

Prints the graph

usage:

let mut g: graphs::Graph = graphs::Graph::new(false); // creates undirected graph
g.print() // prints the graph

pub fn get_topological_order(&mut self) -> Vec<String>

Returns topological sorted order of the vertice of the graph

pub fn get_order(&mut self, node: &String, order: &mut Vec<String>)

pub fn get_vertices(&mut self) -> &mut HashMap<String, Vertex>

pub fn get_edges(&mut self) -> &mut HashMap<(String, String), Edge>

pub fn add_vertex(&mut self, label: String)

Add vertex to the graph

Parameters:

1. label - the label of the vertex which should be of type String

2. value - value of the vertex, any generic

Example

let mut G: graphs::Graph = graphs::Graph::new(false); // create undirected graph
g.add_vertex(String::from("A")); // add vertex to the graph with label A and value 0

pub fn remove_vertex(&mut self, label: String)

Remove vertex and all of its adjacent edges.

Parameters

1. label: The label of the vertex

Example

g.remove_vertex(String::from("A")); // Remove vertex A from the graph G

pub fn add_edge(&mut self, e: (String, String), weight: GNumber)

Adds an edge to the graph (Endpoint vertices must be present in graph)

Parameters

1. (endpoint1, endpoint2) - the two endpoints of the edge each will be of type String

2. weight - The weight of the edge

Example

// Edge with I32 weights having endpoints "A" and "B"
 g.add_edge(
    (String::from("A"), String::from('B')),
    graphs::GNumber::I32(4),
);

// Edge with F32 weights having endpoints "A" and "B"
g2.add_edge(
    (String::from("A"), String::from('B')),
    graphs::GNumber::F32(4.),
);

// Edge with U32 weights having endpoints "A" and "B"
g3.add_edge(
    (String::from("A"), String::from('B')),
    graphs::GNumber::U32(2),
);

pub fn update_edge(&mut self, e: (String, String), weight: GNumber)

Update the weight of an edge to the graph (Edge must be present in graph)

Parameters

1. (endpoint1, endpoint2) - the two endpoints of the edge each will be of type String

2. weight - The weight of the edge

Example

// This will update the value of the edge with endpoint (A, B) to 10 (I32 value)
 g.update_edge(
    (String::from("A"), String::from('B')),
    graphs::GNumber::I32(10),
);

pub fn remove_edge(&mut self, e: (String, String))

Removes an edge from a graph (Endpoint vertices are not affected)

Parameters

1. (endpoint1, endpoint2) - the two endpoints of the edge (type String)

Example

// This will remove edge with endpoints A and B
 g.remove_edge(
    (String::from("A"), String::from('B')),
);

pub fn get_neighbors(&self, label: &String) -> Vec<String>

Input a vertex label (Returns a vector of vertex labels which correspond to the neighbors of the input vertex)

Parameter:

1. label - Label of type String

Return Value:

Returns a vector of labels of all the vertices that are neighbors of this vertex

Example

G.get_neighbors(String::from("A")) // returns all the neighbors of A

// example return: ["B", "C", "D"]. If B, C and D are neighbors of A

pub fn get_out_neighbors(&self, label: &String) -> Vec<String>

Input a vertex label. Returns a vector of vertex labels which correspond to the outgoing neighbors of the input vertex.

Parameter:

1. label - Label of type String

Return Value:

Returns a vector of labels of all the vertices that are outgoing neighbors of this vertex. This is for a directed graph

Example

g.get_out_neighbors(String::from("A")) // returns all the  outgoing neighbors of A

// example return: ["B", "C", "D"].
// A -> B, A -> C, A -> D

pub fn get_in_neighbors(&self, label: &String) -> Vec<String>

Input a vertex label. Returns a vector of vertex labels which correspond to the incoming neighbors of the input vertex.

Parameter:

1. label - Label of type String

Return Value:

Returns a vector of labels of all the vertices that are incoming neighbors of this vertex. This is for a directed graph

Example

G.get_in_neighbors(String::from("A")) // returns all the incoming neighbors of A

// example return: ["B", "C", "D"].
// B -> A, C -> A, D -> A

pub fn read_adjacency_matrix(filename: &str) -> Result<Vec<Vec<u32>>, Error>

Reads an adjacency matrix from a file and returns it as a Vec<Vec<u32>>

pub fn write_adjacency_matrix( matrix: &[Vec<u32>], filename: &str, ) -> Result<(), Error>

Writes an adjacency matrix to a file.

pub fn get_vertex(&mut self, label: &String) -> Option<&mut Vertex>

Function to get the vertex given the label

Parameters:

1. label - Label of the vertex - type String

Return Type:

Returns an Option of type mutable Vertex. If there are no vertex with the provided label - None will be returned

Example

let vertex_A = g.get_vertex(String::from("A")); // this wil return the vertex A which is mutable (We can change the value of the vertex)

Trait Implementations

impl Clone for Graph

fn clone(&self) -> Graph

Returns a duplicate of the value.

const fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.