view src/samer/functions/Quadratic.java @ 0:bf79fb79ee13

Initial Mercurial check in.

/*
 *	Copyright (c) 2000, Samer Abdallah, King's College London.
 *	All rights reserved.
 *
 *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
 *	without even the implied warranty of MERCHANTABILITY or 
 *	FITNESS FOR A PARTICULAR PURPOSE.
 */

package samer.functions;
import  samer.maths.*;
import  samer.core.*;

public class Quadratic extends Function
{	
	double	a, b, c;

	public Quadratic(double a, double b, double c) { 
		this.a = a; this.b = b; this.c = c;
	}

	public double apply(double t) { return c+t*(b+a*t); }
	public String format(String arg) { 
		StringBuffer buf=new StringBuffer();
		boolean f=false;
		if (c!=0) { buf.append(X.string(c)); }
		if (b!=0 || b<0) { 
			if (f) { buf.append(b>0 ? " + " : " - "); f=true; }
			if (b==1 || b==-1) buf.append(arg); 
			else buf.append(X.string(Math.abs(b))).append(arg); 
		}
		if (a!=0) { 
			if (f || a<0) { buf.append(a>0 ? " + " : " - "); f=true; }
			if (a==1 || a==-1) buf.append(arg+"^2"); 
			else buf.append(X.string(Math.abs(b))).append(arg+"^2"); 
		}
		return buf.toString();
	}

	public Function derivative() { return new Linear(2*a,b); }
}