public class Eliptica {
	final double CA=0.0003; // The accuracy is the square of CA.
	public double sn;
	public double cn;
	public double dn;

public Eliptica() {
	sn=dn=cn=0.0;
}

void sncndn(double uu, double emmc){
//Returns the Jacobian elliptic functions sn(u; kc), 
//cn(u; kc), and dn(u; kc). Here uu = u, while
//emmc = k2 c .
	double a,b,c=0.0,d=0.0,emc,u;
	double[] em=new double[14];
	double[] en=new double[14];
	int i,ii,l=0;
	boolean bo;
	emc=emmc;
	u=uu;
	if (emc!=0.0) {
		bo=(emc < 0.0);
		if (bo) {
			d=1.0-emc;
			emc /= -1.0/d;
			u *= (d=Math.sqrt(d));
		}
		a=1.0;
		dn=1.0;
		for (i=1;i<=13;i++) {
			l=i;
			em[i]=a;
			en[i]=(emc=Math.sqrt(emc));
			c=0.5*(a+emc);
			if (Math.abs(a-emc) <= CA*a) break;
			emc *= a;
			a=c;
		}
		u *= c;
		sn=Math.sin(u);
		cn=Math.cos(u);
		if (sn!=0.0) {
			a=cn/sn;
			c *= a;
			for (ii=l;ii>=1;ii--) {
				b=em[ii];
				a *= c;
				c *= dn;
				dn=(en[ii]+a)/(b+a);
				a=c/b;
			}
			a=1.0/Math.sqrt(c*c+1.0);
			sn=(sn >= 0.0 ? a : -a);
			cn=c*sn;
		}
		if (bo) {
			a=dn;
			dn=cn;
			cn=a;
			sn /= d;
		}
	} else {
		cn=1.0/cosh(u);
		dn=cn;
		sn=tanh(u);
	}
}
double cosh(double x){
	return((Math.exp(x)+Math.exp(-x))/2);
}
double tanh(double x){
	return((Math.exp(x)-Math.exp(-x))/(Math.exp(x)+Math.exp(-x)));
}
}

//objeto 
	Eliptica obj=new Eliptica();

//posición del oscilador
 	obj.sncndn((x0*Math.sqrt(cte)*t/lonMuelle),0.5);
	x=x0*obj.cn;
	t+=dt;