Sigmoid function

A sigmoid function is a mathematical function having a characteristic “S”-shaped curve or sigmoid curve.

import math

def basic_sigmoid(x):
s = 1 / (1 + math.exp(-x))
return s

basic_sigmoid(3)

0.9525741268224334

import numpy as np

def sigmoid(x):
s = 1 / (1 + np.exp(-x))
return s

x = np.array([1, 2, 3])
sigmoid(x)

array([ 0.73105858,  0.88079708,  0.95257413])