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# Can anyone suggest me to write a correct and working code for traveling salesman problem using simulated annealing? I got this but there are so many errors:

Asked by Yogesh Shukla on 25 Feb 2013
```% Travellingsalesman problem
```
```% Create random city distribution
```
```n=20;
```
```x=random('unif',-1,1,n,1);
```
```y=random('unif',-1,1,n,1);
```
```gam=1; mu=sign(x);
```
```% End up where you start. Add starting point to end
```
```x=[x' x(1)]';
```
```y=[y' y(1)]';
```
```mu=[mu' mu(1)]'; figure(1); hold off; g=plot(x,y,'.r');
```
```set(g,'MarkerSize',20);
```
```c0=cost(x,y,mu,gam); k=1; % Boltzmanconstant
```
```nt=50; nr=200; % nt: temp steps. nr: city switches each T cp=zeros(nr,nt);
```
```iran=inline('round(random(d,1.5001,n+0.4999))','d','n');
```
```for i=1:nt
```
```T=1.0 -(i-1)/nt
```
```for j=1:nr
```
```% switch two random cities
```
```ic1=iran('unif',n); ic2=iran('unif',n);
```
```xs=x(ic1); ys=y(ic1); ms=mu(ic1);
```
```x(ic1)=x(ic2); y(ic1)=y(ic2); mu(ic1)=mu(ic2);
```
```x(ic2)=xs; y(ic2)=ys; mu(ic2)=ms;
```
```p=random('unif',0,1); c=cost(x,y,mu,gam);
```
```if (c < c0 | p < exp(-(c-c0)/(k*T))) % accept
```
```c0=c;
```
```else % reject and switch back
```
```xs=x(ic1); ys=y(ic1); ms=mu(ic1);
```
```x(ic1)=x(ic2); y(ic1)=y(ic2); mu(ic1)=mu(ic2);
```
```x(ic2)=xs; y(ic2)=ys; mu(ic2)=ms;
```
```end
```
```cp(j,i)=c0;
```
```end
```
```figure(2); plot(reshape(cp,nt*nr,1)); drawnow;
```
```figure(1); hold off; g=plot(x,y,'.r'); set(g,'MarkerSize',20); hold on;
```
```plot(x,y,'b'); g=plot(x(1),y(1),'.g'); set(g,'MarkerSize',30);
```
```p=plot([0 0],[-1 1],'r--'); set(g,'LineWidth',2); drawnow;
```
```end
```

## 2 Comments

Walter Roberson on 25 Feb 2013

If you describe some of the errors, people could help you debug it.

Yogesh Shukla on 25 Feb 2013

??? Undefined function or method 'random'

for input arguments of type 'char'.

Error in ==> salesman at 3

n=20; x=random('unif',-1,1,n,1);

y=random('unif',-1,1,n,1);

## 2 Answers

Answer by Walter Roberson on 25 Feb 2013
Accepted answer

That version of a random number routine is part of the Statistics Toolbox; see http://www.mathworks.com/help/stats/random.html

The Statistics Toolbox is optional extra cost for Academic and Professional licenses. It is, though, included in Student Version licenses, but the toolbox might not be installed by default.

## 16 Comments

Walter Roberson on 27 Feb 2013

What is the purpose of your line

```p=rand(0,1);
```

rand(0,1) creates a 0 x 1 matrix of random numbers -- an empty matrix.

Yogesh Shukla on 27 Feb 2013

I want to generate a random number between 0 and 1. Which function i can use?

Answer by Yogesh Shukla on 26 Feb 2013
Edited by Yogesh Shukla on 26 Feb 2013

Instead of using this routine (ie not using uniform distribution or random function) what else can I change in my code to eliminate errors and make code running. However if I use other function instead of 'random' then I get 'error using ==> ctranspose.. Transpose on ND array is not defined' in following lines:

x=[x' x(1)]';

y=[y' y(1)]';

mu=[mu' mu(1)]';

Thanks for your reply. Please help me because i have my presentation in few days.

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