mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 05:21:09 +00:00
78a0f61b19
* Add Maths / Sigmoid Function * Update Sigmoid Function * Add doctest and type hints * Fix Trim Trailing Whitespace * Fix Error * Modified Black * Update sigmoid.py Co-authored-by: sukyung99 <tnrudsla413@gmail.com> Co-authored-by: Christian Clauss <cclauss@me.com>
40 lines
944 B
Python
40 lines
944 B
Python
"""
|
|
This script demonstrates the implementation of the Sigmoid function.
|
|
|
|
The function takes a vector of K real numbers as input and then 1 / (1 + exp(-x)).
|
|
After through Sigmoid, the element of the vector mostly 0 between 1. or 1 between -1.
|
|
|
|
Script inspired from its corresponding Wikipedia article
|
|
https://en.wikipedia.org/wiki/Sigmoid_function
|
|
"""
|
|
|
|
import numpy as np
|
|
|
|
|
|
def sigmoid(vector: np.array) -> np.array:
|
|
"""
|
|
Implements the sigmoid function
|
|
|
|
Parameters:
|
|
vector (np.array): A numpy array of shape (1,n)
|
|
consisting of real values
|
|
|
|
Returns:
|
|
sigmoid_vec (np.array): The input numpy array, after applying
|
|
sigmoid.
|
|
|
|
Examples:
|
|
>>> sigmoid(np.array([-1.0, 1.0, 2.0]))
|
|
array([0.26894142, 0.73105858, 0.88079708])
|
|
|
|
>>> sigmoid(np.array([0.0]))
|
|
array([0.5])
|
|
"""
|
|
return 1 / (1 + np.exp(-vector))
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|