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Fonction expit - module scipy.special

Signature de la fonction expit

Description

expit.__doc__

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

expit(x)

Expit (a.k.a. logistic sigmoid) ufunc for ndarrays.

The expit function, also known as the logistic sigmoid function, is
defined as ``expit(x) = 1/(1+exp(-x))``.  It is the inverse of the
logit function.

Parameters
----------
x : ndarray
    The ndarray to apply expit to element-wise.

Returns
-------
out : ndarray
    An ndarray of the same shape as x. Its entries
    are `expit` of the corresponding entry of x.

See Also
--------
logit

Notes
-----
As a ufunc expit takes a number of optional
keyword arguments. For more information
see `ufuncs <https://docs.scipy.org/doc/numpy/reference/ufuncs.html>`_

.. versionadded:: 0.10.0

Examples
--------
>>> from scipy.special import expit, logit

>>> expit([-np.inf, -1.5, 0, 1.5, np.inf])
array([ 0.        ,  0.18242552,  0.5       ,  0.81757448,  1.        ])

`logit` is the inverse of `expit`:

>>> logit(expit([-2.5, 0, 3.1, 5.0]))
array([-2.5,  0. ,  3.1,  5. ])

Plot expit(x) for x in [-6, 6]:

>>> import matplotlib.pyplot as plt
>>> x = np.linspace(-6, 6, 121)
>>> y = expit(x)
>>> plt.plot(x, y)
>>> plt.grid()
>>> plt.xlim(-6, 6)
>>> plt.xlabel('x')
>>> plt.title('expit(x)')
>>> plt.show()