Undefined function. Can anyone plz help me!

I followed the textbook and type the exact code. But still it doesn't work. I can not find anything wrong from it, just can not understand why the solution function could not be generated? Can anyone plz help me! Thanks!

    num=[100];
    den=[0.36 1.86 2.5 1];

    K=[2.0 2.2 2.4 2.6 2.8 3.0];
    a=[0.5 0.7 0.9 1.1 1.3 1.5];
    t=0:0.01:5;
    g=tf(num,den);
    k=0;
    for i=1:6;
        for j=1:6;
            gc=tf(K(i)*[1 2*a(j) a(j)^2],[1 0]);
            G=gc*g/(1+gc*g);
            y=step(G,t);
            m=max(y);

            if m<1.10
                k=k+1;
                solution(k,:)=[K(i) a(j) m];
            end
        end
    end

The outcome should be that when I type solution in the command window and a table of figures will be generated, however what I got is just the remind that Undefined function or variable 'solution'.

Answer 1

[Image Analyst]

This line:

solution(k,:)=[K(i) a(j) m];

never gets executed. Use the debugger to figure out why. This is something you will absolutely have to learn to do if you want to write programs in MATLAB. All of us do it, you need to too.

[Claude Liao]

I have already found the problem, when I delete the if statement, the solution function will be generated, however when I add the if statement, it goes wrong. Could please tell me how can I add the if statement properly?

[Image Analyst]

I have no idea why you put that if statement in there. This is what happens when you don't put comments in your code - other people can't maintain your code for you. Why is the if statement in there in the first place? If you don't want it, take it out. I have no idea if it's supposed to be there or not.