MATLAB: Abs and angle of complex number with symbolic object

Question

Hi,

If r=sym('a')*exp(j*sym('b')) is a symbolic object, and

1. if I write abs(r), I get abs(a)…..I need get only "a" without abs

2. if I write angle(r), I get error

??? Undefined function or method 'atan2' for input arguments of type 'sym'.

Error in ==> angle at 14 p = atan2(imag(h), real(h));

Can you help me please? How can I solve this?

Answer 1

There is no "complex argument" function for symbolic variables exposed at the MATLAB level. You can, though, define

arg = @(V) feval(symengine, 'arg', V);

http://www.mathworks.com/help/symbolic/mupad_ref/arg.html