scipy.special.gammainccinv — SciPy v1.15.2 Manual (original) (raw)
scipy.special.gammainccinv(a, y, out=None) = <ufunc 'gammainccinv'>#
Inverse of the regularized upper incomplete gamma function.
Given an input \(y\) between 0 and 1, returns \(x\) such that \(y = Q(a, x)\). Here \(Q\) is the regularized upper incomplete gamma function; see gammaincc. This is well-defined because the upper incomplete gamma function is monotonic as can be seen from its definition in [dlmf].
Parameters:
aarray_like
Positive parameter
yarray_like
Argument between 0 and 1, inclusive
outndarray, optional
Optional output array for the function values
Returns:
scalar or ndarray
Values of the inverse of the upper incomplete gamma function
See also
regularized upper incomplete gamma function
regularized lower incomplete gamma function
inverse of the regularized lower incomplete gamma function
References
Examples
import scipy.special as sc
It starts at infinity and monotonically decreases to 0.
sc.gammainccinv(0.5, [0, 0.1, 0.5, 1]) array([ inf, 1.35277173, 0.22746821, 0. ])
It inverts the upper incomplete gamma function.
a, x = 0.5, [0, 0.1, 0.5, 1] sc.gammaincc(a, sc.gammainccinv(a, x)) array([0. , 0.1, 0.5, 1. ])
a, x = 0.5, [0, 10, 50] sc.gammainccinv(a, sc.gammaincc(a, x)) array([ 0., 10., 50.])