How to improve efficiency of two port matrix calculations?

Hi,

I'm looking for a way to speed up some simple two port matrix calculations. See the below code example for what I'm doing currently. In essence, I create a [Nx1] frequency vector first. I then loop through the frequency vector and create the [2x2] matrices H1 and H2 (all functions of f). A bit of simple matrix math including a matrix left division '\' later, and I got my result pb as a [Nx1] vector. The problem is the loop - it takes a long time to calculate and I'm looking for way to improve efficiency of the calculations. I tried assembling the problem using [2x2xN] transfer matrices, but the mtimes operation cannot handle 3-D multiplications.

Can anybody please give me an idea how I can approach such a calculation without the need for looping through f?

Many thanks: svenr

% calculate frequency and wave number vector

f = linspace(20,200,400);

w = 2.*pi.*f;

% calculation for each frequency w

for i=1:length(w)

    H1(i,1) = {[1, rho*c*k(i)^2 / (crad*pi); 0,1]};

    H2(i,1) = {[1, 1i.*w(i).*mp; 0, 1]};

    HZin(i,1) = {H1{i,1}*H2{i,1}};

    temp_mat = HZin{i,1}*[1; 0];

    Zin(i,1) = temp_mat(1,1)/temp_mat(2,1);

    temp_mat= H1{i,1}\[1; 1/Zin(i,1)];

    pb(i,1) = temp_mat(1,1); Ub(i,:) = temp_mat(2,1);

end

Answer 1

[James Tursa]

If your main stumbling block is doing 3D page-based matrix multiplication, you can try 3rd party submissions from the FEX. E.g., MTIMESX

http://www.mathworks.com/matlabcentral/fileexchange/25977-mtimesx-fast-matrix-multiply-with-multi-dimensional-support

Also there is a small 3D page-based linear solver that might be of interest:

http://www.mathworks.com/matlabcentral/fileexchange/24260-multiple-same-size-linear-solver