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Fixed Endpoints Open Traveling Salesman Problem - Genetic Algorithm

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Fixed Endpoints Open Traveling Salesman Problem - Genetic Algorithm

by Joseph Kirk

 

23 Aug 2008 (Updated 07 Nov 2011)

Finds a near-optimal solution to a "open" variation of the TSP with fixed endpoints using a GA

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Description

TSPOF_GA Fixed Open Traveling Salesman Problem (TSP) Genetic Algorithm (GA)
Finds a (near) optimal solution to a variation of the TSP by setting up a GA to search for the shortest route (least distance for the salesman to travel from a FIXED START to a FIXED END while visiting the other cities exactly once)

Summary:
1. A single salesman starts at the first point, ends at the last point, and travels to each of the remaining cities in between, but does not close the loop by returning to the city he started from
2. Each city is visited by the salesman exactly once

Note: The Fixed Start is taken to be the first XY point, and the Fixed End is taken to be the last XY point

Input:
XY (float) is an Nx2 (or Nx3) matrix of cities
DMAT (float) is an NxN matrix of point to point distances/costs
POPSIZE (scalar integer) is the size of the population (should be divisible by 4)
NUMITER (scalar integer) is the number of desired iterations for the algorithm to run
SHOWPROG (scalar logical) shows the GA progress if true
SHOWRESULT (scalar logical) shows the GA results if true

Output:
OPTRTE (integer array) is the best route found by the algorithm
MINDIST (scalar float) is the cost of the best route

Example:
n = 50;
xy = 10*rand(n,2);
popSize = 60;
numIter = 1e4;
showProg = 1;
showResult = 1;
a = meshgrid(1:n);
dmat = reshape(sqrt(sum((xy(a,:)-xy(a',:)).^2,2)),n,n);
[optRoute,minDist] = tspof_ga(xy,dmat,popSize,numIter,showProg,showResult);

Example:
n = 50;
phi = (sqrt(5)-1)/2;
theta = 2*pi*phi*(0:n-1);
rho = (1:n).^phi;
[x,y] = pol2cart(theta(:),rho(:));
xy = 10*([x y]-min([x;y]))/(max([x;y])-min([x;y]));
popSize = 60;
numIter = 1e4;
showProg = 1;
showResult = 1;
a = meshgrid(1:n);
dmat = reshape(sqrt(sum((xy(a,:)-xy(a',:)).^2,2)),n,n);
[optRoute,minDist] = tspof_ga(xy,dmat,popSize,numIter,showProg,showResult);

Example:
n = 50;
xyz = 10*rand(n,3);
popSize = 60;
numIter = 1e4;
showProg = 1;
showResult = 1;
a = meshgrid(1:n);
dmat = reshape(sqrt(sum((xyz(a,:)-xyz(a',:)).^2,2)),n,n);
[optRoute,minDist] = tspof_ga(xyz,dmat,popSize,numIter,showProg,showResult);

Acknowledgements

Traveling Salesman Problem Genetic Algorithm inspired this file.

Required Products MATLAB
MATLAB release MATLAB 7.12 (R2011a)
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fixed endpoints, open variation, optimization, traveling salesman problem, tsp
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Updates
02 Sep 2008

updated help notes, description

02 Jun 2009

Added 3D capability.

07 Nov 2011

Bug fix. Minor cosmetic updates.

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