a simple evoulutionary algorithm 1. the user can enter any user defined string as the evolutionary tareget up to 30 characters max

clc
clear
t= 'Hell world!';
numRands=length(t);
tlength=numRands;
source=t(ceil(rand(1,tlength)*numRands));

fitval = fitness(source, t);

i = 0;

while 1

     i = i + 1;

     m = mutate(source);

     fitval_m = fitness(m, t);

     if fitval_m < fitval

fitval = fitval_m;

source = m;

fprintf('%5i %5i %14s', i, fitval_m, m);

     end

     if fitval == 0

break

     end

end

function fitval = fitness(source, t)

     fitval = 0

     for i = 1 : length(source)

fitval = fitval + (double(t(i)) - double(source(i))) ^ 2;

     end

end

function parts = mutate(source)

     parts = source;

     charpos = randi(length(source)) - 1;

     parts(charpos) = char(double(parts(charpos)) + (randi(3)-2));

end

[Walter Roberson]

Is there a question here?

[yared Zeleke]

The quation is

1. The user can enter any user defined string as the evolutionary target up to 30 characters max.

2. The program should randomly generate the first ‘source’ from which to mutate.

3. The program should print-out every 100th iteration the iteration and the current mutated source and its fitness in the command window.

I tried but I have some eror I need some one to correct it to me finally the result should be the same as t

Answer 1

[Walter Roberson]

You have

     charpos = randi(length(source)) - 1;

The result of that can be 0 because randi might have generated a 1. You then have

     parts(charpos) = char(double(parts(charpos)) + (randi(3)-2));

but charpos can be 0 so you can be attempting to index at location 0, which is not defined.

I do not know why you are subtracting 1 at the point?

[yared Zeleke]

exactlly that was wrong 1 should not be substracted