Daniel@0: % GENERAL GRAPH THEORY CLASS
Daniel@0: %
Daniel@0: % CAVE: Any special application oriented stuff 
Daniel@0: % should be outside here
Daniel@0: 
Daniel@0: classdef Graph < DiGraph
Daniel@0:  
Daniel@0: methods
Daniel@0: 
Daniel@0:     % ---
Daniel@0: % Constructor
Daniel@0: % ---
Daniel@0: function G = Graph(V, E)
Daniel@0:      
Daniel@0:     if nargin == 1
Daniel@0:         % ---
Daniel@0:         % this uses an imput grpaph
Daniel@0:         % to create a new graph
Daniel@0:         % ---
Daniel@0:         G = Graph.copy(V);
Daniel@0:         
Daniel@0:     elseif nargin == 2
Daniel@0:         
Daniel@0:         if numel(V) == size(V,2)
Daniel@0:             G.V = V;
Daniel@0:         else
Daniel@0:             G.V = V';
Daniel@0:         end
Daniel@0: 
Daniel@0:         G.E = E;
Daniel@0:     end
Daniel@0: end
Daniel@0: function w = edge(G, V1, V2)
Daniel@0:     
Daniel@0:     sm = min([V1, V2]);
Daniel@0:     bg = max([V1, V2]);
Daniel@0:     
Daniel@0:     w = G.E(sm, bg);
Daniel@0: end
Daniel@0: 
Daniel@0: % ---      
Daniel@0: % add an edge
Daniel@0: % the undirected case: G.E is triangular
Daniel@0: % ---
Daniel@0: function add_edge(G, V1, V2, weight)
Daniel@0:     
Daniel@0:     G.add_node(V1);
Daniel@0: 	G.add_node(V2);
Daniel@0:     
Daniel@0:     sm = min([V1, V2]);
Daniel@0:     bg = max([V1, V2]);
Daniel@0:     
Daniel@0:     if  G.E(sm, bg) == 0
Daniel@0: 
Daniel@0:         % save weight
Daniel@0:         G.E(sm, bg) = weight;
Daniel@0:     else
Daniel@0:         
Daniel@0:         join_edge(G, V1, V2, weight);
Daniel@0:     end
Daniel@0: end
Daniel@0: 
Daniel@0: % remove an edge
Daniel@0: function remove_edge(G, V1, V2)
Daniel@0:     
Daniel@0:     sm = min([V1, V2]);
Daniel@0:     bg = max([V1, V2]);
Daniel@0:     
Daniel@0:     G.E(sm,bg) = 0;
Daniel@0: end
Daniel@0: 
Daniel@0: % ---
Daniel@0: % sets the edge without considering earlier weights
Daniel@0: % ---
Daniel@0: function set_edge(G, V1, V2, weight)
Daniel@0:     
Daniel@0:     sm = min([V1, V2]);
Daniel@0:     bg = max([V1, V2]);
Daniel@0:     
Daniel@0:     G.E(sm, bg) = weight;
Daniel@0:     
Daniel@0: end
Daniel@0: 
Daniel@0: % ---
Daniel@0: % Graph-specific functions
Daniel@0: % in the undirected case, these are the same
Daniel@0: % ---
Daniel@0: function c = children(G, Vid)
Daniel@0: 
Daniel@0:     c = [find(G.E(Vid,:) > 0) find(G.E(:,Vid) > 0)'];
Daniel@0: end
Daniel@0: 
Daniel@0: function p = parents(G, Vid)
Daniel@0: 
Daniel@0:     p = [find(G.E(Vid,:) > 0) find(G.E(:,Vid) > 0)'];
Daniel@0: end
Daniel@0: 
Daniel@0: % ---
Daniel@0: % Vertex Degree
Daniel@0: % ---
Daniel@0: function out = degree(G, V)
Daniel@0:     
Daniel@0:     out = sum(G.E(V,:) > 0) + sum(G.E(:,V) > 0);
Daniel@0: end
Daniel@0: 
Daniel@0: % ---
Daniel@0: % Vertex Degree
Daniel@0: % ---
Daniel@0: function out = degree_in(G, V)
Daniel@0:     
Daniel@0:     out = sum(G.E(V,:) > 0) + sum(G.E(:,V) > 0);
Daniel@0: end
Daniel@0: 
Daniel@0: % ---
Daniel@0: % Vertex Degree
Daniel@0: % ---
Daniel@0: function out = degree_out(G, V)
Daniel@0:     
Daniel@0:     out = sum(G.E(:,V) > 0) + sum(G.E(:,V) > 0);
Daniel@0: end
Daniel@0: 
Daniel@0: end
Daniel@0: 
Daniel@0: 
Daniel@0: methods (Static)
Daniel@0:    function G = copy(Gin)
Daniel@0:        
Daniel@0:        if strcmp(class(Gin), 'Graph')
Daniel@0:            
Daniel@0:            G = Graph(Gin.V, Gin.E);
Daniel@0:            G.Vlbl = Gin.Vlbl;
Daniel@0:            
Daniel@0:        else
Daniel@0:            warning ('cannot copy graph, casting instead')
Daniel@0:            G = Graph.cast(Gin);
Daniel@0:        end
Daniel@0:         
Daniel@0:    end
Daniel@0:    
Daniel@0:    function G = cast(Gin)
Daniel@0:        
Daniel@0:         % ---
Daniel@0:         % this uses an imput grpaph
Daniel@0:         % to create a new digraph
Daniel@0:         % ---
Daniel@0:         G = Graph();
Daniel@0:         
Daniel@0:         % ---
Daniel@0:         % Add the input graph to the empty one
Daniel@0:         % ---
Daniel@0:         G.add_graph(Gin);
Daniel@0:    end
Daniel@0: end
Daniel@0: end