public override double CalculateActivation(double weightedInputs)
{
double coshx = Math.Cosh((2.0 / 3.0) * weightedInputs);
double denominator = Math.Cosh((4.0 / 3.0) * weightedInputs) + 1;
return 4.57573 * coshx * coshx / (denominator * denominator);
}