How to use two different variables in few complex equation in for loop?

I have some problem in MATLAB

Now,I'm solving the problem about the transmission of silver superlens by MATLAB.but when I use for loop and get some trouble. could anyone helpme, thank you

lambda=365e-9

k0=2*pi/lambda

epsilon1=2.193+0.009i

epsilonm=-2.16078+0.273i

epsilon3=2.193+0.009i

for i=10:12

dm=i

for j=0:15*k0

kx=j

d1=10e-9

d3=10e-9

kz1=((epsilon1*k0^2)-kx.^2).^0.5

kz3=((epsilon3*k0^2)-kx.^2).^0.5

kzm=((epsilonm*k0^2)-kx.^2).^0.5

r12=((epsilonm*kz1)-(epsilon1*kzm))./((epsilonm*kz1)+(epsilon1*kzm))

r23=((epsilon3*kzm)-(epsilonm*kz3))./((epsilon3*kzm)+(epsilonm*kz3))

t12=(2*(epsilonm*kz1))./((epsilonm*kz1)+(epsilon1*kzm))

t23=(2*(epsilon3*kzm))./((epsilon3*kzm)+(epsilonm*kz3))

data(i)=(t12.*t23.*exp(i*kzm*dm))./((1+r12.*r23.*exp(i*2*kzm*dm)))

end

end

Answer 1

[Cris LaPierre]

The variable data will only contain values for the case when j==15*k0. If you want to store all values, data must be a matrix. Your assigment would have to be something like data(i,j) = ...

Something like this might work. However, the values of data are all NaN. This is because your numbers are extremely large.

    lambda=365e-9;
    k0=2*pi/lambda;
    epsilon1=2.193+0.009i;
    epsilonm=-2.16078+0.273i;
    epsilon3=2.193+0.009i;
for i=10:12;
    dm=i
    for j=0:15
            kx=j*k0;
            d1=10e-9;
            d3=10e-9;
            kz1=((epsilon1*k0^2)-kx.^2).^0.5;
            kz3=((epsilon3*k0^2)-kx.^2).^0.5;
            kzm=((epsilonm*k0^2)-kx.^2).^0.5;
            r12=((epsilonm*kz1)-(epsilon1*kzm))./((epsilonm*kz1)+(epsilon1*kzm));
            r23=((epsilon3*kzm)-(epsilonm*kz3))./((epsilon3*kzm)+(epsilonm*kz3));
            t12=(2*(epsilonm*kz1))./((epsilonm*kz1)+(epsilon1*kzm));
            t23=(2*(epsilon3*kzm))./((epsilon3*kzm)+(epsilonm*kz3));
            data(i-9,j+1)=(t12.*t23.*exp(i*kzm*dm))./((1+r12.*r23.*exp(i*2*kzm*dm)));
    end
end

[CHUN-HUNG Liu]

Thank you for your reply.

And I have another question

If I want to record the data to get More details.

Something (first loop)like this :

i=1:0.01:10

.

.

.

then,data(i-9,j+1) will be rewrite --->

I change ''j+1'' into ''(j*10)-9'' => data(i-9,(j*10)-9)=...

finally,it say something woring:

Index in position 2 is

invalid. Array indices

must be positive integers

or logical values.

How can I use code to discribe this?

thanks for your helping.

Answer 2

[Cris LaPierre]

It's i that you changed, so you shouldn't have to do anything with j.

In this case, I'd recommend first creating a variable for your time, and then use the indeces of that variable as your loop counter. For example

var1=1:0.01:10;
for i=1:length(var1)
    .
    .
    .
    data(i,j+1)=
end

I would actually recommed doing something similar with j. That way, you can adjust the number ranges you use without having to change downstream code. It makes your code much more robust.

[CHUN-HUNG Liu]

I got it!

thanks a million.