I get an error "Error : undefined function or variable 'randcoosen' " from line 1 and I dont fully understand what the lines 3 to 10 are doing? Thanks

ma=RandChooseN(probs,M); --line1
pa=RandChooseN(probs,M); --line2

xp=ceil(rand(1,M)*(Nt-1));  --line3
    pop(1:2:popsize,:)=[pop(ma,1:xp(1)) pop(pa,xp(1)+1:Nt)]; --line4
    pop(2:2:popsize,:)=[pop(pa,1:xp(1)) pop(ma,xp(1)+1:Nt)];  --line5
    
    nmut=ceil((popsize-1)*Nt*mutrate); --line6
    mrow=ceil(rand(1,nmut)*(popsize-1))+1; --line 7
    mcol=ceil(rand(1,nmut)*Nt); --line8
    for ii=1:nmut --line9
        pop(mrow(ii),mcol(ii))=abs(pop(mrow(ii),mcol(ii))-1); % toggles bits --line10
    end
    end

Answer 1

[Geoff Hayes]

Ifeatu - RandChooseN is not a built-in MATLAB function nor is (likely) part of any toolbox or from the File Exchage. The closest reference I could find to this function was from this site Mathematical Modeling class notes. You will need to download this file (or I suppose write it from scratch) and update your MATLAB search path to include this file so that it can be found when you reference it from other code. See What is the MATLAB Search Path? for more details.

Answer 2

[Walter Roberson]

Your code does not contain any referece to "randcoosen". MATLAB is case sensitive, so randcoosen would not match RandCooseN. Which also would not match RandChooseN since missing h is important.

RandChooseN is not a mathworks provided routine.

It looks to me as if you might be using https://www.mathworks.com/matlabcentral/answers/327664-is-my-genetic-algorithm-result-correct or perhaps https://hrcak.srce.hr/file/253498 . The second of those includes source for its RandChooseN

[Walter Roberson]

http://people.whitman.edu/~hundledr/courses/M350F14/M350/RandChooseN.m is another source