File Exchange

## K-Shortest Path- Yen's algorithm

version 1.0 (11.6 KB) by

Based on Yen’s algorithm, returns the K shortest paths between a source and a destination.

Updated

This function is based on Yen's k-Shortest Path algorithm:
J. Y. Yen, "Finding the K shortest loopless paths in a network", Management Science 17:712–716, 1971.

It returns:
1) [shortestPaths]: the list of K shortest paths (in cell array 1xK)
2) [totalCosts] : costs of the K shortest paths (in array 1xK)
Yen's algorithm prevents loops.

This function calls a slightly modified/simplified function dijkstra() (submitted by Xiaodong Wang, 2004)

The Network/Graph of N nodes is fed in the form of a NXN netCostMatrix which must have positive weights/costs.

IMPORTANT: see 'TestKShortestPath.m' and 'Test graph (case 1).pdf' for netCostMatrix format.

William Clelland

### William Clelland (view profile)

As a follow up to Sulimon Sattari's comment. In order to accelerate the code substantially, we need to preallocate the temp array in the included dijkstra.m file. To do so replace line 31 through 38 with

temp = zeros(n,1);
for h = 1:n
if ~visited(h) % in the tree;
temp(h) = distance(h);
else
temp(h) = inf;
end
end;

Hope this helps someone!

Mason Song

Excellent

Hari

### Hari (view profile)

Thank You for the code. Is it possible to modify this so as to list the k shortest paths between all OD pairs?

shashi bhushan jha

Thank You!

Sulimon Sattari

### Sulimon Sattari (view profile)

Thanks for the file! I've been looking for a way to compute "all" shortest paths between two nodes and this gives me a way to do so.

I was able to speed the code up considerably (about a factor of 10) by pre-allocating "temp" in dijkstra.m, this is simply heeding MATLAB's warning to preallocate for speed. I'd recommend doing the same if anyone is bogged down with larger networks.

Yuxuan Liang

### Yuxuan Liang (view profile)

It cost much time in large matrix, omg

Umer Rasheed

### Umer Rasheed (view profile)

Takes a very very long time to compute if matrix is large.

Mohammed

### Mohammed (view profile)

Hello I'm new to Matlab, so can any one please tell me how to pass input argument for this code.?

zhou jianshan

### zhou jianshan (view profile)

mohammed sportman

### mohammed sportman (view profile)

it is correct (when i run it some problem appear

Jort Gemmeke

### Jort Gemmeke (view profile)

Works like a charm. And as far as I could see, the only shortest path algorithm on File Exchange that returns an N-best list.

##### MATLAB Release
MATLAB 7.8 (R2009a)