view src/samer/functions/RaleighLogPrior.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.*;

/**
	Density is linear near zero, rising to a peak, decaying
	with a Gaussian tail.
*/

public class RaleighLogPrior extends Function
{
	public final double apply(double t) { return 0.5*t*t - Math.log(t); }
	public String format(String t) { return "LogRaleigh("+t+")"; }
	public Function derivative() { 
		return new Function() {
			public String format(String t) { return "dLogRaleigh("+t+")"; }
			public final double apply(double t) { return t-1/t; }
		};
	}
}