def useFahlmanActivationFunction(self):
        """
        Change the network to use Fahlman's default activation function for all layers.
        Must be called after all layers have been added.
        """
        self.activationFunction = self.activationFunctionFahlman
        self.ACTPRIME = self.ACTPRIME_Fahlman
        self.actDeriv = self.actDerivFahlman
        for layer in self:
            layer.minTarget, layer.minActivation = -0.5, -0.5 
            layer.maxTarget, layer.maxActivation = 0.5, 0.5