Java Number Power powi(double x, int p)

Description

Fast loop for computing Math.pow(x, p) for p >= 0 integer.

License

Open Source License

Parameter

Parameter	Description
x	Base
p	Exponent

Return

Math.pow(x, p)

Declaration

public static double powi(double x, int p) 

Method Source Code

//package com.java2s;
/*/* w ww. ja  v  a2s .  c  om*/
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2013
 Ludwig-Maximilians-Universit?t M?nchen
 Lehr- und Forschungseinheit f?r Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program 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 Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Main {
    /**
     * Fast loop for computing {@code Math.pow(x, p)} for p >= 0 integer.
     * 
     * @param x Base
     * @param p Exponent
     * @return {@code Math.pow(x, p)}
     */
    public static double powi(double x, int p) {
        if (p < 0) { // Fallback for negative integers.
            return Math.pow(x, p);
        }
        double ret = 1.;
        for (; p > 0; p >>= 1) {
            if ((p & 1) == 1) {
                ret *= x;
            }
            x *= x;
        }
        return ret;
    }
}

Related

1. powerTrim(String s)
2. powerType(float power)
3. powerX(long a, long b)
4. powExact(long x, int y)
5. powf(float v1, float v2)
6. powInt(int base, int exponent)
7. powLLL(double[] a, double b)
8. powSqrt(double x, double y)