Simple logistic regression model using raw python and numpy.
Image source: Tess FernandezThe sigmoid function, which is also known as the standard logistic function is defined as \sigma(x) = . The sigmoid function needs to satisfy three properties P1 - P3.
Let \sigma(x) be the sigmoid function, it needs to satisfy.
- P1 \lim_{x \to -inf} \sigma(x) = 0, \lim_{x \to inf} \sigma(x) = 1, \lim_{x \to 0} \sigma(x) = 1/2