Artificial Intelligence By Example

Logistic function

The logistic sigmoid provides one of the best ways to normalize the weight of a given output. This will be used as the activation function of the neuron. The threshold is usually a value above which the neuron has a y=1 value; or else it has y=0. In this case, the minimum value will be 0 because the activation function will be more complex.

The logistic function is represented as follows.

• e represents Euler's number, or 2.71828, the natural logarithm. 
• x is the value to be calculated. In this case, x is the result of the logistic sigmoid function.

The code has been rearranged in the following example to show the reasoning ...