How to wrap angle in radians to [-pi/2 pi/2]?

I want to limit an angle in radians to be between -pi/2 and pi/2. I have tried to modify the function wrapToPi, but it does not give me the desired result. Here is my attempt:

    function lambda = wrapToHalfPi(lambda)
        q = (lambda < -pi/2) | (pi/2 < lambda);
        lambda(q) = wrapTo2Pi(lambda(q) + 3*pi/2) - 3*pi/2;

Thanks!

[Image Analyst]

Do you mean "limit" to mean "clamp" or "clip", or to mean "mod". For example if the input was (3/4)pi, would you want the answer to be pi/4 (distance past pi/2) or pi/2 (clamped at that value) or something else?

Answer 1

[Stephen23]

Not quite the same, because this gives [-pi/2,pi/2), but it might be interesting for you nonetheless:

 out = mod(lambda+pi/2,pi)-pi/2

To get the range [-pi/2,pi/2], something like this:

 tmp = mod(lambda+pi/2,pi);
 out = tmp+pi*(lambda>0&tmp==0)-pi/2

[EllaM]

Thanks for you answer! Could you please explain a bit further what you mean?

[Stephen23]

@EllaM: try it with some values of lambda, and see what it does.