MATLAB: Unassigned variables and accessing them from outside the function

Question

I have this code:

function [zr,w,R,q,mat] = test(z)  
lambda = 1;
w0 = 1;  
zr = (pi*w0^2)/lambda;
w = w0*sqrt(1+(z/zr)^2);
R = z + zr^2/z;
q = z + 1i*zr;
mat = [1 z; 0 1];  
end

but I not want to have to assign lambda and w0 ( or even z for that matter ), i want them to just stay variables UNLESS I assign them … This is because often it's easier to interpret one variable in terms of the other instead of just having some number… so inputting

[zr,w,R,q,mat] = test(z)

should return the variables exactly how they look inside the function:

    zr = 
          (pi*w0^2)/lambda
    w = 
          w0*sqrt(1+(z/zr)^2)
    R = 
          z + zr^2/z
    q = 
          z + 1i*zr
    mat = 
          1 z
          0 1

also, how come these don't exist outside of the function? I can't call q anymore for example after executing test because it doesn't appear to exist anymore.

EDIT:

assigning them as global worked as far as keeping the values assigned by the function :] yay! i don't know if that's the proper way, but it worked XD … still not sure how to return unassigned variable tho …

Answer 1

If you have the symbolic toolbox, use it.

syms lambda phi
zr = (sym('pi')*w0^2)/lambda;