error in particle swarm optimization code

i got this code from mathworks

clear all;

numofdims = 30;

numofparticles = 50;

c1 = 2;

c2 = 2;

numofiterations = 1000;

V = zeros(50, 30);

initialpop = V;

Vmin = zeros(30, 1);

Vmax = Vmin;

Xmax = ones(30, 1) * 100;

Xmin = -Xmax;

pbestfits = zeros(50, 1);

worsts = zeros(50, 1);

bests = zeros(50, 1);

meanfits = zeros(50, 1);

pbests = zeros(50, 30);

initialpop = Xmin + (Xmax - Xmin) .* rand(numofparticles, numofdims);

X = initialpop;

fitnesses = testfunc1(X);

[minfit, minfitidx] = min(fitnesses);

gbestfit = minfit;

gbest = X(minfitidx, :);

for i = 1:numofdims

        Vmax(i) = 0.2 * (Xmax(i) - Xmin(i));

        Vmin(i) = -Vmax(i);
    end

for t = 1:1000

        w = 0.9 - 0.7 * (t / numofiterations);

        for i = 1:numofparticles

            if(fitnesses(i) < pbestfits(i))

                pbestfits(i) = fitnesses(i);

                pbests(i, :) =  X(i, :);

            end

        end

        for i = 1:numofparticles

            for j = 1:numofdims

                V(i, j) = min(max((w * V(i, j) + rand * c1 * (pbests(i, j) - X(i, j))...

                    + rand * c2 * (gbest(j) - X(i, j))), Vmin(j)), Vmax(j));

                X(i, j) = min(max((X(i, j) + V(i, j)), Xmin(j)), Xmax(j));

            end

        end

        fitnesses = testfunc1(X);

        [minfit, minfitidx] = min(fitnesses);

        if(minfit < gbestfit)

            gbestfit = minfit;

            gbest = X(minfitidx, :);

        end

        worsts(t) = max(fitnesses);

        bests(t) = gbestfit;

        meanfits(t) = mean(fitnesses);

end

when is execute

i am getting error in line "initialpop = Xmin + (Xmax - Xmin) .* rand(numofparticles, numofdims);"

Error using *

Inner matrix dimensions must agree.

please help me

Answer 1

[Walter Roberson]

That code was taken from a user posting asking for help. The code is not functional.

The user appears to have copied from a 2012 post in stackoverflow, as the same code and same error appeared then.

When you run into trouble with code that you copied, you should be asking the author of the code. Or writing your own code. If you had written the code then we could at least have asked you what the intent of the line was.