NodeAddWeightedInputs

public class Node {

    private List<Double> weights;
    private double activation = 0;

    public void addWeightedInputs(List<Double> inputs) {
        if (inputs.size() != weights.size()) throw new IllegalArgumentException(
            "Input size (" + inputs.size() +
                ") doesn't match weight's size (" + weights.size() + ").\nThis: " + this );

        double sum = 0;

        for (int i = 0; i < inputs.size(); i++) {
            sum += weights.get(i) * inputs.get(i);
        }

        activation = sigmoidFunction(sum);
        System.out.println("Act: " + activation + ", Sum: " + sum);
    }

    private static double sigmoidFunction(double activation) {
        return 1.0 / (1 + Math.pow(Math.E, -activation));
    }

}