//
// PRIVATE METHODS
//
private Matrix createDerivativeMatrix(Vector lastInducedField) {
List<Double> lst = new List<Double>();
for (int i = 0; i < lastInducedField.size(); i++) {
lst.Add(layer.getActivationFunction().deriv(
lastInducedField.getValue(i)));
}
return Matrix.createDiagonalMatrix(lst);
}