scipy.special.gammasgn#
- scipy.special.gammasgn(x, out=None) = <ufunc 'gammasgn'>#
- 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:
- xarray_like
- Real argument 
- outndarray, optional
- Optional output array for the function values 
 
- Returns:
- scalar or ndarray
- Sign of the gamma function 
 
 - See also - Notes - The gamma function can be computed as - gammasgn(x) * np.exp(gammaln(x)).- References [dlmf]- NIST Digital Library of Mathematical Functions https://dlmf.nist.gov/5.2#E1 - Examples - >>> import numpy as np >>> import scipy.special as sc - It is 1 for - x > 0.- >>> sc.gammasgn([1, 2, 3, 4]) array([1., 1., 1., 1.]) - It alternates between -1 and 1 for negative integers. - >>> sc.gammasgn([-0.5, -1.5, -2.5, -3.5]) array([-1., 1., -1., 1.]) - It can be used to compute the gamma function. - >>> x = [1.5, 0.5, -0.5, -1.5] >>> sc.gammasgn(x) * np.exp(sc.gammaln(x)) array([ 0.88622693, 1.77245385, -3.5449077 , 2.3632718 ]) >>> sc.gamma(x) array([ 0.88622693, 1.77245385, -3.5449077 , 2.3632718 ])