# 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)).

gamma

the gamma function

gammaln

log of the absolute value of the gamma function

loggamma

analytic continuation of the log of the gamma function

References

dlmf

NIST Digital Library of Mathematical Functions https://dlmf.nist.gov/5.2#E1