求用matlab解最短路问题的程序要用Dijkstra算法找出任意两点间的最短路径．希望用MATLAB或LINGO编程求解.求程序,

求用matlab解最短路问题的程序要用Dijkstra算法找出任意两点间的最短路径．希望用MATLAB或LINGO编程求解.求程序,
求用matlab解最短路问题的程序
要用Dijkstra算法找出任意两点间的最短路径．希望用MATLAB或LINGO编程求解.求程序,

求用matlab解最短路问题的程序要用Dijkstra算法找出任意两点间的最短路径．希望用MATLAB或LINGO编程求解.求程序,
% Dijkstra's Shortest Path
%
% final = dijkstra( A,x,y )
%
% Description:returns the shortest path from x to y given adjacency
% matrix A.Utilizes Dijkstra's shortest path algorithm.
%
% A = adjacency matrix of the graph (includes point x and y)
% x = intial node
% y = terminal node
% IN = set of nodes whose shortest path from x is known
% z,p = temporary nodes
% d = vector of lengths from initial point.i.e.d(p) = x to p
% s = vector of the previous node on a shortest path for any node
%
% Author:Josh Eads
% Date:1/23/2006
function final = dijkstra( A,x,y )
%modify A so that lengths of 0 are invalid (-1)
A(find(A == 0)) = NaN;
%initialize IN to include only x
IN = x;
%initialize s
s = zeros(1,length(A));
%initialize d & d(x) (distance to self)
d = zeros(1,length(A));
d(x) = 0;
%loop through all the nodes in A
for z = 1:length(A)
%don't calculate values already in IN
%if (find(IN == z))
if isWithin(IN,z)
%grab the distance from x to z from A (-1 denotes unreachable)
d(z) = A(x,z);
%set the previous node to x
s(z) = x;
end
end
%process nodes into IN
%while y isn't in set IN
%while (find(IN == y))
while isWithin(IN,y)
tempMin = [];
%add the node not in IN with the minimum distance into IN
for z = 1:length(A)
%if z isn't in IN
%if (find(IN == z))
if isWithin(IN,z)
tempMin = [tempMin,d(z)];
end
end
%find the minimum value from tempMin
p = min(tempMin);
%find the minimum distance nodes
search = find(d == p);
%cycle through all the minimum distance nodes until one not in IN is
%found
for i = 1:length(search)
search = find(d == p);
%store in p if the node isn't in IN
if( isWithin(IN,search(i)) )
p = search(i);
break;
end
end
%add node p into IN
IN = [IN,p];
%recompute d for all non-IN nodes,and adjust s
for z = 1:length(A)
%if z isn't in IN
%if (find(IN == z))
if isWithin(IN,z)
oldDistance = d(z);
%if the new path is shorter for z,update d(z)
d(z) = min(d(z),d(p) + A(p,z));
%if the new and old distances don't match,update s(z)
if (d(z) == oldDistance)
s(z) = p;
end
end
end
end
%write the shortest path to final
final = y;
z = y;
while (z == x) == 0
final = [final,s(z)];
z = s(z);
end
final=fliplr(final);
% isWithin Function
% source = matrix to search through
% search = item to search for
%
% returns - true if search is within source
function truth = isWithin(source,search)
truth = 0;
for i = 1:length(source)
if(source(i) == search)
truth = 1;
end
end