mars.tensor.special.gammasgn#

mars.tensor.special.gammasgn(x, **kwargs)[source]#

Sign of the gamma function.

It is defined as

\[\begin{split}\text{gammasgn}(x) = \begin{cases} +1 & \Gamma(x) > 0 \\ -1 & \Gamma(x) < 0 \end{cases}\end{split}\]

where \(\Gamma\) is the gamma function; see gamma. This definition is complete since the gamma function is never zero; see the discussion after [dlmf].

Parameters: x (array_like) – Real argument
Returns: Sign of the gamma function
Return type: scalar or ndarray

Notes

The gamma function can be computed as gammasgn(x) * np.exp(gammaln(x)).