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## Traveling Salesman Problem - Genetic Algorithm

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Finds a near-optimal solution to a TSP using a GA

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Editor's Note: This file was selected as MATLAB Central Pick of the Week

TSP_GA Traveling Salesman Problem (TSP) Genetic Algorithm (GA)
Finds a (near) optimal solution to the TSP by setting up a GA to search
for the shortest route (least distance for the salesman to travel to
Summary:
1. A single salesman travels to each of the cities and completes the
route by returning to the city he started from
2. Each city is visited by the salesman exactly once

Input:
USERCONFIG (structure) with zero or more of the following fields:
- XY (float) is an Nx2 matrix of city locations, where N is the number 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
- SHOWWAITBAR (scalar logical) shows a waitbar if true

Input Notes:
1. Rather than passing in a structure containing these fields, any/all of
these inputs can be passed in as parameter/value pairs in any order instead.
2. Field/parameter names are case insensitive but must match exactly otherwise.

Output:
RESULTSTRUCT (structure) with the following fields:
(in addition to a record of the algorithm configuration)
- OPTROUTE (integer array) is the best route found by the algorithm
- MINDIST (scalar float) is the cost of the best route

Usage:
tsp_ga
-or-
tsp_ga(userConfig)
-or-
resultStruct = tsp_ga;
-or-
resultStruct = tsp_ga(userConfig);
-or-
[...] = tsp_ga('Param1',Value1,'Param2',Value2, ...);

Example:
% Let the function create an example problem to solve
tsp_ga;

Example:
% Request the output structure from the solver
resultStruct = tsp_ga;

Example:
% Pass a random set of user-defined XY points to the solver
userConfig = struct('xy',10*rand(50,2));
resultStruct = tsp_ga(userConfig);

Example:
% Pass a more interesting set of XY points to the solver
n = 100;
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]));
userConfig = struct('xy',xy);
resultStruct = tsp_ga(userConfig);

Example:
% Pass a random set of 3D (XYZ) points to the solver
xyz = 10*rand(50,3);
userConfig = struct('xy',xyz);
resultStruct = tsp_ga(userConfig);

Example:
% Change the defaults for GA population size and number of iterations
userConfig = struct('popSize',200,'numIter',1e4);
resultStruct = tsp_ga(userConfig);

Example:
% Turn off the plots but show a waitbar
userConfig = struct('showProg',false,'showResult',false,'showWaitbar',true);
resultStruct = tsp_ga(userConfig);

Nicolas LI

### Nicolas LI (view profile)

Awesome, thanks !

Nathan Parrish

Joseph Kirk

### Joseph Kirk (view profile)

@Madina, what you seem to be describing is a *VRP*, but this code is for the *TSP* so it does not use constraints like travel time.

Hi, I need help with imposing some constraints. For example split the nodes into two sets depending on the type of car i need.
impose time constraint of travel time from start to end. Last minimum time from pick up point till destination. How can i do that in this code?
thank you

RobertQ leong

Joseph Kirk

### Joseph Kirk (view profile)

@Ricardo, there is a variation for the "open" TSP here:
http://www.mathworks.com/matlabcentral/fileexchange/21196

Ricardo Reis

### Ricardo Reis (view profile)

Very nice code you made. I have a small doubt if anyone could help me, if I don't want a closed path what should I change around line 168? thanks in advance!

reza marvasti

Fan Zhang

wonderful work！

Renaud

### Renaud (view profile)

Hi,

I was just wondering why you wrote a code with a Genetic Algorithm rather then using a Lin-Kernighan Heuristic approach?

Thanks for the code!
Best,
Renaud

Joseph Kirk

### Joseph Kirk (view profile)

@Vera, you should not need to modify the code itself -- just pass different inputs that are specific to the problem you are trying to solve.

@yogita, if you have a specific question about my code, I would be happy to answer it.

cagatay odabasi

Vera Bajic

### Vera Bajic (view profile)

Hi! First of all thank you for your code, it is amazing! I am trying to use this algorithm on Europe map, but i don't know how to modify the code, could you help?

yogita tandel

### yogita tandel (view profile)

hello sir

i m m.tech power system student.

sir u have any idea for genetic algorithm mppt technique for pv cell in partial shading condition

please help me sir how to generate duty cycle using genetic algorithm with fitness function of power p = v * i

Joseph Kirk

### Joseph Kirk (view profile)

@Lilly,

If your coordinates are latitude/longitude, then you should create a distance matrix for the point-to-point distances in the units you desire and pass that matrix in as the DMAT input.

If no distance matrix is provided as an input, my code assumes the inputs are in a Cartesian coordinate system and computes the pair-wise Euclidean distances. In the case of non-Cartesian systems like geographic latitude/longitude, this is undesirable, which is one of the reasons my code offers the option of passing in a pre-computed distance matrix.

Lilly

### Lilly (view profile)

If I insert a longitude and latitude as input, and the shortest distance is 2.6702, so 2.6702 stand for what ? Meaning here is it km or coordinate ?

Joseph Kirk

### Joseph Kirk (view profile)

@Tonia, I think the choice of configuration values (like POPSIZE and NUMITER) is an exercise best left to the user. There is a trade-off between computation time and solution convergence rate. If you choose a higher population size, fewer iterations should be required to converge to a near-optimal solution, but each iteration will take a little longer to process. Alternatively, you could decrease the population size and increase the number of iterations.

And POPSIZE must be divisible by 4 because of the way good solutions in the current population are propagated to the next iteration. (I randomly group 4 citizens at a time, take the best of those four, and pass that one on to the next iteration. I then perform 3 different mutations on that best-of-four citizen and replace the 3 lesser solutions in the population with the mutated versions for the next iteration).

Hello joseph,Thanks a lot for your code.I would like to explain me please in a problem with 100 cities what should be the number of POPSIZE and why this must be divisible by 4.I don't really understand what's the reason of : popSize = 4*ceil(popSize/4); .

Na Li

### Na Li (view profile)

Thanks very much, it is helpful. I understand why you did not use crossover opration, but I am confused why there is not a mutation rate. although i think it is right, i can not convince myself. please help!

nelson alves

### nelson alves (view profile)

Thank you a lot. I get it to work now! @Joseph

Joseph Kirk

### Joseph Kirk (view profile)

@nelson, the reason you are getting an error is because you are only passing the DMAT input instead of both XY and DMAT. When a DMAT is provided, the XY points are only used for plotting purposes, but I still do a consistency check to make sure they have the same number of points. If you do not have XY points for your problem, you can always pass in "dummy" values.

So in your case, you could call the function as follows:
>> result = tsp_ga('xy',rand(5,2),'dmat',X);

Joseph Kirk

### Joseph Kirk (view profile)

@Aalaa, please see some of the comments below. I do not use a crossover operator but rather 3 different mutation operators.

Aalaa Magableh

### Aalaa Magableh (view profile)

Thanks a lot for your response, I wont to know what is the Selection function and Crossover function used in this code and what is the
Crossover ratio.

nelson alves

### nelson alves (view profile)

Please tell me what am I doing wrong:
This is my distance matrix for a travelers salesman problem.
>> X=[0 150 120 330 190; 150 0 50 290 150;120 50 0 240 100;330 290 240 0 140;190 150 100 140 0]

X =

0 150 120 330 190
150 0 50 290 150
120 50 0 240 100
330 290 240 0 140
190 150 100 140 0

>> userConfig = struct('dmat',X)

userConfig =

dmat: [5x5 double]

>> resultStruct = tsp_ga(userConfig)

Error using tsp_ga (line 134)
Invalid XY or DMAT inputs!

Joseph Kirk

### Joseph Kirk (view profile)

@Aalaa, there is an "optRoute" field in the output variable structure that stores the best route found. As for optimizing the input parameters, that is an exercise best left up to the user.

Aalaa Magableh

### Aalaa Magableh (view profile)

Hello Joseph thanks a lot for your code. I have apply it on 2000 cities but how i can get the order of the cities in the last route?
whats about the best number of iteration and the other GA operator you sujest me to use with pop. size 2000Thanks

Joseph Kirk

### Joseph Kirk (view profile)

@Gunjan, for a TSP with 10 cities, the route 1-2-3-4-5-6-7-8-9-10 is the same as the route 5-6-7-8-9-10-1-2-3-4, so if you have to start at city number 5, all you have to do is shift the values before the 5 in the resulting solution to the end of the list.

Regarding citations, here is a useful blog post: http://blogs.mathworks.com/community/2010/12/13/citing-file-exchange-submissions/

Gunjan Indapurkar

### Gunjan Indapurkar (view profile)

Hello Joseph your code helped a lot. I have few more question
If I have a 10 city problem and if I have to start from a predetermined city say city number 5, then how do I do it? Also I would like to refer/cite your work as much as possible, how do I do it? Thanks.

Gunjan Indapurkar

### Gunjan Indapurkar (view profile)

Hello Joseph,
My From/To distance chart has a dash '-' for diagonal elements. How do I enter this matrix in dmat command with diagonal elements set to dash ' - ' or infinity.
Thanks

Twinkle katiyar

Joseph Kirk

### Joseph Kirk (view profile)

@katiyar, see some of the comments below for why I did not implement a crossover operator. There is, however, a mutation operator -- 3 of them in fact.

Twinkle katiyar

### Twinkle katiyar (view profile)

ga algorithm also have crossover and mutation funtion. But this code doesn't have these function?? Is there any who have ga code including crossover and mutation. please send me. I really need it.

mina

### mina (view profile)

hi. i want to make a WSN and implement one of the intelligent routing protocols on it.for start i dont know how to simulate a WSN. would anyone help me or send me anything helpful?
thank you

Joseph Kirk

### Joseph Kirk (view profile)

@Ravisasthiri, you can pass the points into the function as inputs. Please see the numerous examples provided in the help notes.

Ravisasthiri P

MAYUR PAILWAR

Emre Yakut

### Emre Yakut (view profile)

Hi, Dear Joseph Kirk. I have found your tsp genetic matlab code. I am studying tsp matlab code. My data set is presented to additional your information. One store and seven shop, I am trying to find which best route. How can I make the appropriate my data in your code to take into account?

I would be glad if you can help.

Best Regards.

Emre YAKUT
Osmaniye Korkut Ata University

chengzhi

Joseph Kirk

### Joseph Kirk (view profile)

@Binayak, look in the help notes for examples and input/output options.

Binayak dutta

### Binayak dutta (view profile)

The code is amazing. The coder is a life saver. But please tell me how to specify the xy coordinates in the code as I'm a novice in matlab. Please!!!!

Sven

Joseph Kirk

### Joseph Kirk (view profile)

@Sven, thanks for the suggestions. I'll look into overhauling the interface.

Sven

### Sven (view profile)

Nice work Joseph as usual. Note however a frustration: The function has reasonable defaults, but these are ONLY accessed if no subsequent inputs are given. For instance, if I want to call the function with default inputs but NOT show results (the 6th input), I can no longer use defaults for ANY of the other inputs and MUST provide them all. This is really just a frustration with the distMap matrix (I know, just a couple of lines, but I'll bet the default is being used most of the time) as the others are simple scalar inputs, but the interface design in general could do with a tweak. I suggest some logic to check each and use defaults if empty (which could be implemented without changing the function IO), or in general I find the inputParser class to be useful for this style of not-necessarily-ordered user inputs.

Oh, and I think that numStaticIter may be a useful parameter too: the user could specify the number of iterations in which - if the distance hasn't reduced - the loop kicks out to save computation time.

Joseph Kirk

### Joseph Kirk (view profile)

@Larry, the XY coordinates are only randomly created if no inputs are provided to the function. If you pass a set of XY points, the function will use them.

You can also pass in a distance matrix of point-to-point distances. If you do not provide one, my function computes the pairwise Euclidean distances. However, for latitude and longitude points, this is probably not desirable. You should create a distance matrix in the units you desire and pass that in as the second input.

Larry

### Larry (view profile)

Hi Joseph,
Can I first say that this is an amazing code and thank you so much for it's creation.
I was wondering how it would be possible to change the xy co-ordinates from being randomly selected to being set points (for example longitude and latitude).
Many thanks

yuantao song

very good

Joseph Kirk

### Joseph Kirk (view profile)

@Pedro, thanks for the link. I had not seen the paper previously, but yes, it does appear to have used this code.

Pedro p

### Pedro p (view profile)

Hello Joseph, You might already know about it, but i found a paper discussing this algorithm, I didnt find the right references to your work though:
http://www.ijsce.org/attachments/File/v3i2/B1514053213.pdf

Joseph Kirk

### Joseph Kirk (view profile)

@chikodragon, I do not use the crossover operator in my implementation. I don't think it is necessarily an essential component of a GA. I have implemented a handful of different versions of the GA (with various mutation/crossover operator combinations) to solve the TSP, and what I have found is that the crossover operator tends to be quite destructive (it makes large changes to a given route) and therefore rarely improves a decent solution. So my code uses 3 different mutation operators with the intent to make modifications that are more likely to improve the best solutions. (I randomly group 4 citizens at a time, take the best one of those four, and pass that one on to the next generation. I then perform 3 mutations on that best-of-four citizen and pass the mutated versions on to the next generation as well).

chikodragon

### chikodragon (view profile)

hello mr kirk thank you very much. which parts of your coding are discussing crossover? I have not seen it. thank you for your attention.

Fredrik

Fredrik

### Fredrik (view profile)

Hi Joseph, I was wondering how I can specify a home point, if I start a TSP search mid journey. Using your previously explained method, it also sets this point as start, but I only want it as stop. Any tricks to do this?
Example:
I have computed a path, and something happends midway so I have to compute a new path, but this time [0 0 0] is not start location, only stop, and [30 90 5] is start =)

Fredrik

### Fredrik (view profile)

Hi Mr. Kirk, I was wondering if you have any documentation (i.e scientific report/article) on your work demonstrated here. I have successfully implemented part of your code in my masters thesis project, involving cognitive control of quadrocopters, and would like to refer to your work as much as possible.

Victor

Joseph Kirk

### Joseph Kirk (view profile)

Victor, the population size is part of the GA configuration - it has nothing to do with the TSP in general...

Victor

### Victor (view profile)

Hello Joseph.

I am missing something. Could you please explain, what is the relationship between popSize variable and the TSP problem?

Joseph Kirk

### Joseph Kirk (view profile)

Fredrik, the "showResult" flag does precisely that.

Fredrik

### Fredrik (view profile)

Is there any easy way of displaying ONLY the best solution as output, after the iterations are done, instead of the changing optRoute?

Fredrik

### Fredrik (view profile)

Thanks a lot Joseph, I have also managed to implement your script with some modifications in simulink, where I get a set of waypoints as input =)

Joseph Kirk

### Joseph Kirk (view profile)

Fredrik,
In the standard formulation of the TSP, the optimal solution can start at any city. If you want to force the solution to start at a specific city, you can manipulate the output as follows:

Supposing that you have requested "optRoute" as an output and that you want the solution to start at the first city, you can type the following into the Command Window:

>> index = find(optRoute == 1);
>> finalRoute = optRoute([index:end 1:index-1])

Mathias

thank you

Fredrik

### Fredrik (view profile)

Hi I was wondering, how can I set an initial starting point/stop points? when I run the algorithm for mywaypoints, the starting position becomes the 6th visited city, but that is where I start, so ofcourse I want that to be the initial position.

asma

asma

Joseph Kirk

Yuan

### Yuan (view profile)

I find your next Open Traveling Salsman Solution, and it works as well good. Nice job :)

Yuan

### Yuan (view profile)

Excuse me Joseph, can you explain a bit how to use it if I don't want a return loop? I mean only from a starting point towards an unknown end but with smallest distance. Thank you in advance.

Newmat

### Newmat (view profile)

@ Joseph Kirk
Thank you so much!! This really helped me!

@all
I have 230 nodes. Is it usual for the ga-algorithm that it takes about 30000 Iterations to find a good path?

Joseph Kirk

### Joseph Kirk (view profile)

Newmat, that is because the code is a function. The stuff that happens inside is essentially a black box as far as the stuff outside is concerned. Certain variables are passed as output if you request them (see examples) but if you really need the internal variables, I suggest adding a line at the end of the function that saves the variables to a .mat file. [i.e. add the line: "save('TSPvariables.mat')" without the quotes after the last line of code in the function]

Newmat

### Newmat (view profile)

What do I have to change inside the script to keep all variables? When the script has finished, you can't check any variables anymore. For example, if I type in Matlab's command line "xy" (to get the values of xy) the variable is not defined anymore. It is like if the clear-command has been executed.
Does anybody know? It is very important!
Thank you!

Emmanuel Luevano

### Emmanuel Luevano (view profile)

Hi, Is it posible to convert this m file into c code using the emlc function?

Emmanuel Luevano

### Emmanuel Luevano (view profile)

@Joseph Hi, Is there a way to use it in SIMULINK?

Mojeeb

thanks!

Erdal Bizkevelci

Tristan Ursell

### Tristan Ursell (view profile)

A simple to understand implementation, and can be easily modified :)

UNIMAS

### UNIMAS (view profile)

hi joseph..may i know where is the fitness function inside your program?

UNIMAS_sk

### UNIMAS_sk (view profile)

please send me modified file if you can to angelgurl_aireen@yahoo.com

UNIMAS_sk

### UNIMAS_sk (view profile)

@Joseph thanks for ur explanation, i now start to understand what u try to do. now, u used mutation as an operators to generate new generations. i believe it is possible if we want to modify the operators in ur sourcecode to use crossover instead of mutation. I am curios as to compares the result of using mutation and crossover operators. i'm trying to do this but keep on failing since i'm new to MATLAB coding. If u can, could u please show me the modified version for the crossover operators?

nur lydia

### nur lydia (view profile)

thank for the above explanation,however when i study your previous program there are different in both coding. could you explain the different ...thanks you

Joseph Kirk

### Joseph Kirk (view profile)

@Derek, no, but I save the score of the best solution as the function runs. You could modify the file so this variable gets passed as an output.

@Unimas, a potential TSP solution is scored by the length of the route, which we are trying to minimize. I am NOT calculating "fitness" in the traditional sense (as a score between 0 and 1, with 1 being the best) but rather scoring various solutions relative to each other and selecting the shorter routes.

UNIMAS_sk

### UNIMAS_sk (view profile)

great one! i need to ask though, if i were to modified this file, how do i change the fitness functions and its value? i am not even sure what fitness function that u used in the sourcecode since i'm so new to this. the selection method and operators too -_- it would be great if someone can explain that to me. i am also in fuzzy state of how this fitness criteria results are evaluated

Derek O'Connor

### Derek O'Connor (view profile)

Has anybody tested the quality vs numIters of this function?

That is, minDist/optDist as numIters increases.

JOHN ROBINSON

Joseph Kirk

### Joseph Kirk (view profile)

Thierry/Mark, no particular reason except that I originally developed only a small number of files (just the standard TSP and standard MTSP) and it seemed to make sense at the time to submit them separately. Then the list kept growing as more and more people asked me for variations. So they were submitted over a relatively long span of time, but when I update them, the changes show up all at once and hindsight makes it apparent that submitting a single "toolbox" might have made more sense. (But now external sites link to some of the files, so I hesitate to remove them and form a toolbox).

Tero, did you have any success with the modified file I emailed to you?

Tero Tuohioja

### Tero Tuohioja (view profile)

Hello Joseph, without knowing this problem well, can I have 1/TSP easily.. meaning I want the longest possible route

Mark Shore

### Mark Shore (view profile)

Hello Joseph. Just out of curiosity, is there a reason you submitted 11 different variants on this problem as separate files rather than one zipped file containing all of them, with descriptions, or (admittedly more work) a single function allowing the different options to be called?

Joseph Kirk

### Joseph Kirk (view profile)

Will, yes, there is a very good reason. Let me explain. "Distance" is a rather intuitive but perhaps misleading term. For example, you may want to provide my function with geographic coordinates (Latitude/Longitude). However, such a coordinate system is not Cartesian. Therefore, relying on my calculation of the distances may be tenuous at best. In this case, it may be more appropriate to compute "great circle distance" values or something similar to determine the actual distance between each point. I could also envision users wishing to compute the distance along roads, for example, rather than straight-line distances. There are any number of other reasons not to use the simple Euclidean distance that is the default for my function. Thus, perhaps it would be more accurate to think of this input as a "cost" matrix rather than a distance matrix. My function attempts to minimize the cost of the TSP path. And I deemed it appropriate to allow users to provide their own inputs in whatever cost/distance form they would like to choose.

Will Campbell

### Will Campbell (view profile)

Great stuff. I'm curious, is there a particular reason that you pass dmat as an input? Couldn't it always be calculated within the function itself?

Sam

### Sam (view profile)

who could tell me about the selection method that has been used in this program.

nikhil

Avinash

very useful.

Abdullah Y?lmaz

Joseph Kirk

### Joseph Kirk (view profile)

tim: POP_SIZE must be divisible by 4 because of the way good solutions in the current population are propagated to the next iteration.

(I randomly group 4 citizens at a time, take the best one of those four, and pass it on to the next generation. I then perform 3 different mutations on that best-of-four citizen and pass the mutated versions on to the next generation).

tim

### tim (view profile)

can someone please tell me why POP_SIZE must be divisible by 4? Please! thank you!

Masoud Allahkarami

### Masoud Allahkarami (view profile)

thanks!

Srinivas Raparthi

### Srinivas Raparthi (view profile)

Great. Very useful. Thx.

Joseph Kirk

### Joseph Kirk (view profile)

Alex, my code is a slight deviation from the "standard" genetic algorithm, but it has all the essential components of a GA (abstract representation of possible solutions, individual fitness evaluation, a population of potential solutions, and a method of propagating good solutions and forming new, potentially better, solutions).

There IS selection AND elitism, actually, but you are right about crossover. I don't think it is necessarily an essential component of a GA. I have implemented a handful of different versions of the GA (with various mutation/crossover operator combinations) to solve the TSP, and what I have found is that the crossover operator tends to be quite destructive (it makes large changes to a given route) and therefore rarely improves a decent solution. So my code uses 3 different mutation operators with the intent to make modifications that are more likely to improve the best solutions. (I randomly group 4 citizens at a time, take the best one of those four, and pass it on to the next generation. I then perform the 3 mutations on that best-of-four citizen and pass the mutated versions on to the next generation).

Alex Ter-Sarkissov

### Alex Ter-Sarkissov (view profile)

Great implementation, fast and furious, but...where is a genetic algorithm? There's no crossover, no selection, no elitism. It's more of a population-based hill climbing/simulated annealing, I guess.

Thierry Dalon

### Thierry Dalon (view profile)

How about making a TSP Toolbox with all your TSP contributions? (around 15)!

dokuzyuzseksen yuzseksen

thankss..

xu jinpeng

very good!
thanks

shaima A.I

### shaima A.I (view profile)

so good ..
and very useful
but it would be better if you explain the graphical result

thanks so much

Mahdieh

### Mahdieh (view profile)

this was awesome, nice job
though for 1000 points, took very long ...

hudmem ira

### hudmem ira (view profile)

thanks nice written

Naresh Kolla

This would be better if it is extended by taking some more conditions

Sandip Vijay

reza ghanbari

good

me me

i need a guide on to use distance between cities instead of coordinates.do u have any idea?u can email me if possible.

Antoine S

Great. Very useful. Thx.

beh mal

Fernando Castro

Your program is very good. Congratulation. I will need to do something close to your program, but I will use the distances between the cities, and not the coordinates.
Do you have something to help me?
You can email-me, if possible.
Thanks a lot.
Regards

Fernando Castro

Very good. Congratulation.
I'm need to somethind very close to your program, but I will use the distance between the cities, and not the coordinates.
Do you have something to help me?
You can send it to my email:
thanks

tom wiechet

hi.tankas

Dimitri Shvorob

Just to clarify: the author does not use Direct Search and Genetic Algorithm toolbox, but codes up a GA routine from scratch.

Yongguk Kim

thx

tsp+ga+code source

thank you so much..

Husnul Hidayat

Thank u

kazim akbulut

Michael Kleder

Very useful. Well written. Really nice job.

rana salem

John D'Errico

I tested the options, they are now operative. So John A may have downloaded it before the new version was installed. It runs much faster with no plot updates too.

John A

m file does not appear to support Options listed in description.

shahin masti

John D'Errico

Nicely written. Good help. Nice graphics for the solution. But think about it - this is not actually a really useful tool. Its mainly a nice demo. A true tool that could be used to solve a TSP would allow the user to turn off the graphics.

I'd happily raise my rating to a 5 if the author provided a switch to turn off the graphics (as nice as they are.) If there are any parameters that will allow a user to improve the result for specific problems, they too should be controllable, with documentation as to what they do.