Rounds down the value to the nearest lower power^2 value. - Java java.lang

Java examples for java.lang:Math Calculation

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Description

Rounds down the value to the nearest lower power^2 value.

Demo Code

/*/*from  w  w  w .  j av  a 2 s . co  m*/
 *   __               .__       .__  ._____.           
 * _/  |_  _______  __|__| ____ |  | |__\_ |__   ______
 * \   __\/  _ \  \/  /  |/ ___\|  | |  || __ \ /  ___/
 *  |  | (  <_> >    <|  \  \___|  |_|  || \_\ \\___ \ 
 *  |__|  \____/__/\_ \__|\___  >____/__||___  /____  >
 *                   \/       \/             \/     \/ 
 *
 * Copyright (c) 2006-2011 Karsten Schmidt
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * http://creativecommons.org/licenses/LGPL/2.1/
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
//package com.java2s;

public class Main {
    /**
     * Log(2)
     */
    public static final float LOG2 = (float) Math.log(2);

    /**
     * Rounds down the value to the nearest lower power^2 value.
     * 
     * @param x
     * @return power^2 value
     */
    public static final int floorPowerOf2(int x) {
        return (int) Math.pow(2, (int) (Math.log(x) / LOG2));
    }
}

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