expit

scikitplot.experimental._cy_experimental.expit(x0)

Compute the sigmoid (expit) of a scalar input.

The sigmoid function maps a real-valued input to the interval (0, 1) and is defined as:

\[\operatorname{expit}(x) = \frac{1}{1 + e^{-x}}\]

This function is widely used in logistic regression and other models in machine learning and statistics.

Parameters:

x0dfg_number_t

Scalar input value. Can be of type float, double, or long double.

Returns:

dfg_number_t

The sigmoid of the input value, with the same type as x0.

See also

logit

Inverse of the sigmoid function.

log_expit

Logarithm of the sigmoid function.

Notes

This is a Cython-accelerated implementation using the dfg_number_t typedef, which controls the precision (e.g., float, double, or long double).

Added in version 0.3.9.

Examples

>>> expit(0.0)
0.5

>>> expit(0.5)
0.6224593312018546