The Sigmoid Function, σ (x), is used to squish all rational numbers into a value from 0 to 1. The function is commonly used in deep learning to train AI by reducing the range of numbers given to a different function. The other function assesses the AI's actions and assigns a fitness score used to tell the AI whether it should improve into this direction or try a new tactic. However, there is another variation of the Sigmoid function called the Hyperbolic Tangent, tanh (x), which squishes the numbers from -1 to 1 instead of 0 to 1. The blue line is the ordinary Sigmoid function, and the lime line is the Hyperbolic Tangent function. I have increased the size of the two lines so it is easier to see the comparison.
