Java sqr sqrt(double n)

Description

sqrt

License

Apache License

Declaration

public static double sqrt(double n) 

Method Source Code

//package com.java2s;
/**/*  w  ww .j a v a2s . co  m*/
 * Copyright 2008 - 2012
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * 
 * @project loon
 * @author cping
 * @email?javachenpeng@yahoo.com
 * @version 0.3.3
 */

public class Main {
    static private final int BIG_ENOUGH_INT = 16 * 1024;
    static private final double BIG_ENOUGH_ROUND = BIG_ENOUGH_INT + 0.5f;

    public static double sqrt(double n) {
        return Math.round(n);
    }

    public static int sqrt(int n) {
        int s = (n + 65536) >> 1;
        for (int i = 0; i < 8; i++) {
            s = (s + div(n, s)) >> 1;
        }
        return s;
    }

    static public final float sqrt(float a) {
        return (float) Math.sqrt(a);
    }

    public static double round(double n) {
        return Math.round(n);
    }

    public static int round(int n) {
        if (n > 0) {
            if ((n & 0x8000) != 0) {
                return (((n + 0x10000) >> 16) << 16);
            } else {
                return (((n) >> 16) << 16);
            }
        } else {
            int k;
            n = -n;
            if ((n & 0x8000) != 0) {
                k = (((n + 0x10000) >> 16) << 16);
            } else {
                k = (((n) >> 16) << 16);
            }
            return -k;
        }
    }

    public static int round(float x) {
        return (int) (x + BIG_ENOUGH_ROUND) - BIG_ENOUGH_INT;
    }

    public static int div(int x, int y) {
        long z = (((long) x) << 32);
        return (int) ((z / y) >> 16);
    }
}

Related

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2. sqr(int x)
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4. sqrt(double a)
5. sqrt(double d)
6. sqrt(double value)
7. sqrt(double value)
8. sqrt(double x, int precision)
9. sqrt(final double i)