# Activation Functions

## Name

Activation Functions -- Constants representing activation functions.

## Description

These constants represent the activation functions available within the fann library.
The list will grow over time, but probably not shrink.

**Constants**

- FANN_THRESHOLD
*Execution only* - Threshold activation function.

This activation function gives output that is either 0 or 1.

- FANN_THRESHOLD_SYMMETRIC
*Execution only* - Threshold activation function.

This activation function gives output that is either -1 or 1.

- FANN_LINEAR
*Can not be used in fixed point* - Linear activation function.

This activation function gives output that is unbounded.

- FANN_SIGMOID
Sigmoid activation function. One of the most used activation functions.

This activation function gives output that is between 0 and 1.

- FANN_SIGMOID_STEPWISE
Stepwise linear approximation to sigmoid. Faster than sigmoid but a bit less precise.

This activation function gives output that is between 0 and 1.

- FANN_SIGMOID_SYMMETRIC
Symmetric sigmoid activation function, AKA tanh. One of the most used activation functions.

This activation function gives output that is between -1 and 1.

- FANN_SIGMOID_SYMMETRIC_STEPWISE
Stepwise linear approximation to symmetric sigmoid. Faster than symmetric sigmoid but a bit less precise.

This activation function gives output that is between -1 and 1.