samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.units;
samer@0: import  samer.core.*;
samer@0: import  samer.maths.*;
samer@0: 
samer@0: public class EnergyOperator implements Filter
samer@0: {
samer@0: 	double	u1=0, u2=0;	// previous two values
samer@0: 
samer@0: 	public EnergyOperator()	{}
samer@0: 
samer@0: 	public void dispose() {}
samer@0: 
samer@0: 	public double filter( double u0)
samer@0: 	{
samer@0: 		double	y=u1*u1 - u0*u2; 
samer@0: 		u2=u1; 
samer@0: 		u1=u0;
samer@0: 
samer@0: 		return y;
samer@0: 	}
samer@0: }
samer@0: