class ActivationFunctions {

    public static final float tanh(final float x) {
       // x = x*2/3;
       // float a=1.7159;
       final float e2x = (float)Math.exp(2*x);   
       return (e2x-1) / (e2x+1); // calculate tanh 
    }

    private  ActivationFunctions();

}