Using variable legend in for loop

Hii there,

So, I have this code wherein I want to vary k from 4 to 9 but in doing that leg_str shows empty values for some cells and hence is resulting in error. How can I rectify this?

n0 = 1;

n1 = 2;

n2 = 1;

n3 = 2;

d1 = 0.1;

d2 = 0.2;

lam = 3:0.1:7;

th = 0;

phi1 =(d1./lam).*sqrt((n1));

phi2 = (d2./lam).*sqrt((n2));

for k = 4:1:6

z = zeros(size(lam));

for j = 1:numel(lam)

D0 = [2 2; n0 -n0];

D1 = [2 2;n1 -n1];

D2 = [2 2; n2 -n2];

D3 = [2 2;n3 -n3];

P1 = [exp(-1i.*phi1(j)) 1; 1 exp(1i.*phi1(j))];

P2 = [exp(-1i*phi2(j)) 1; 1 exp(1i*phi2(j))];

M = D0*([D1*P1*D2*P2]^(k))*D3;

z(j) = M(2,1)./M(1,1);

end

leg_str{k} = ['k = ' num2str(k)];

plot(lam,abs(z));hold on

end

legend(leg_str);

Answer 1

[Askic V]

Not really sure what you're trying to achieve, especially because abs(z) is always about 0.5, but regarding the legend, I think this would be what you asked for.

n0 = 1; n1 = 2; n2 = 1; n3 = 2;
d1 = 0.1;
d2 = 0.2;
lam = 3:0.1:7;
th = 0;
phi1 =(d1./lam).*sqrt((n1));
phi2 = (d2./lam).*sqrt((n2));
ii = 1;
for k = 4:1:6
    z = zeros(size(lam));
     for j = 1:numel(lam)
            D0 = [2 2;  n0 -n0];
            D1 = [2 2;n1 -n1];
            D2 = [2 2; n2 -n2];
            D3 = [2 2;n3 -n3];
            P1 = [exp(-1i.*phi1(j)) 1; 1 exp(1i.*phi1(j))];
            P2 = [exp(-1i*phi2(j)) 1; 1 exp(1i*phi2(j))];
            M = D0*([D1*P1*D2*P2]^(k))*D3;
            z(j) = M(2,1)./M(1,1);
     end
 leg_str{ii} = ['k = ' num2str(k)];
 ii = ii + 1;
 plot(lam,abs(z));hold on
end
legend(leg_str);

[Ashi Khajotia]

Hello, thanks for the answer. It is just a dummy code!