dijkstra.m

运用dijkstra算法计算最短路的程序

function [path, totalCost, farthestPreviousHop, farthestNextHop] = dijkstra(n, netCostMatrix, s, d, farthestPreviousHop, farthestNextHop)
visited(1:n) = 0;
distance(1:n) = inf;    % it stores the shortest distance between each node and the source node;
parent(1:n) = 0;
distance(s) = 0;
for i = 1:(n-1),
    temp = [];
    for h = 1:n,
         if visited(h) == 0   % in the tree;
             temp=[temp distance(h)];
         else
             temp=[temp inf];
         end
     end;
     [t, u] = min(temp);    % it starts from node with the shortest distance to the source;
     visited(u) = 1;       % mark it as visited;
     for v = 1:n,           % for each neighbors of node u;
         if ( ( netCostMatrix(u, v) + distance(u)) < distance(v) )
             distance(v) = distance(u) + netCostMatrix(u, v);   % update the shortest distance when a shorter path is found;
             parent(v) = u;    %update its parent;
         end;             
     end;
end;
path = [];
if parent(d) ~= 0   % if there is a path!
    t = d;
    path = [d];
    while t ~= s
        p = parent(t);
        path = [p path];
        if netCostMatrix(t, farthestPreviousHop(t)) < netCostMatrix(t, p)
            farthestPreviousHop(t) = p;
        end;
        if netCostMatrix(p, farthestNextHop(p)) < netCostMatrix(p, t)
            farthestNextHop(p) = t;
        end;
        t = p;      
    end;
end;
totalCost = distance(d);
return;