MATLAB: Wrong matrix multiplication answer

Question

Hi,

This multiplication gets a wrong answer:

E=[Eopt(1) 0];

coupler=[sqrt(0.9) 1i*sqrt(0.1);1i*sqrt(0.1) sqrt(0.9)];

Eout=coupler*E(1);

The answer:

Eout =

   9.4868 + 0.0000i  -0.0000 + 3.1623i
  -0.0000 + 3.1623i   9.4868 + 0.0000i

I am multiplying a 2×2 with a 2×1 matrix, so the result should be a 2×1 matrix.

Why is that?

Thanks

Answer 1

No, you are multiplying a 2x2 matrix with a scalar, the first element of E.

Did you mean?

Eout = coupler * E;