Module « scipy.special »

Fonction gammainccinv - module scipy.special

Signature de la fonction gammainccinv

Description

gammainccinv.__doc__

gammainccinv(x1, x2, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])

gammainccinv(a, y)

Inverse of the upper incomplete gamma function with respect to `x`

Given an input :math:`y` between 0 and 1, returns :math:`x` such
that :math:`y = Q(a, x)`. Here :math:`Q` is the 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
----------
a : array_like
    Positive parameter
y : array_like
    Argument between 0 and 1, inclusive

Returns
-------
scalar or ndarray
    Values of the inverse of the upper incomplete gamma function

See Also
--------
gammaincc : regularized upper incomplete gamma function
gammainc : regularized lower incomplete gamma function
gammaincinv : inverse of the regularized lower incomplete gamma
    function with respect to `x`

References
----------
.. [dlmf] NIST Digital Library of Mathematical Functions
          https://dlmf.nist.gov/8.2#E4

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.])