csgn

Robert Israel — Sun, 17 Jul 2011 11:51:58 Z

csgn is a complex version of the signum function. It is 1 for a number in the right half-plane and -1 for a number in the left half-plane. It will typically occur when using evalc on an expression containing square roots of complex expressions. For example:

> evalc(sqrt(a+b*I));

Note that any expression for this will have to be discontinuous on the negative real axis (which is the branch cut of the principal branch of the square root), and this discontinuity is provided by the csgn.

In your case, the result of evalc contains

and

Assumptions such as beta > 0, Q > 0 should remove the need for csgn.

MaplePrimes - answers and comments on Question, why does evalc give csgn?

csgn