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

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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

  2 Comments

yared Zeleke
yared Zeleke on 30 Mar 2018
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

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Accepted Answer

Walter Roberson
Walter Roberson on 31 Mar 2018
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?

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