探索各種隨機函數(Java環境)

1.Wichman-Hill 隨機數產生器

Excel的隨機函數曾用的方法,參考文獻:

Wichman, B.A. 和 I.D. Hill,Algorithm AS 183:An Efficient and Portable Pseudo-Random Number Generator,《Applied Statistics》,31,188-190,1982。 Wichman, B.A. 和 I.D. Hill,Building a Random-Number Generator,BYTE,第127-128 頁,1987 年 3 月。 Rotz, W. 和 E. Falk,D. Wood 和 J. Mulrow,A Comparison of Random Number Generators Used in Business,發表於 2001 年在佐治亞州亞特蘭大市舉行的“統計學聯合會議”上。


/**
 * This is a method of Wichman-Hill random number generator.
 * 
 * @param x
 * A seed for generator.
 * @return A float random value between [0.0,1.0)
 */
public static float randomWH(java.lang.Integer x) {   int[] seed = new int[3];
   seed[0] = (171 * x) % 30269;
   seed[1] = (172 * (30000 – x)) % 30307;
   seed[2] = (170 * x) % 30323;   return (x / Math.abs(x)) 
           * (seed[0] / 30269.0F + seed[1] / 30307.0F + seed[2] / 30323.0F) % 1.0F; 
}

[[1, 0.26327664], [2, 0.26885703], [3, 0.27443743], [4, 0.28001782], [5, 0.28559822], [6, 0.29117858], [7, 0.296759], [8, 0.30233938], [9, 0.3079198], [10, 0.31350017], [11, 0.31908056], [12, 0.324661], [13, 0.33024135], [14, 0.33582175], [15, 0.34140214]] 平均時間很神奇的都是0-1ms,我的天哪裏錯了嗎?
探索各種隨機函數(Java環境)

2.RSA 隨機數產生器

RSA公鑰算法大家都不會不熟悉吧,公認很靠譜的密鑰算法。這裏就是用了RSA的隨機算法。參考:

Wikipedia – RSA problem 其公式:C = (x * exp P) mod N(P是質數,N是兩個質數之積)


/**
 * This is a method of RSA.
 * 
 * @param x
 *            A seed for generator.
 * @return A float random value between [0.0,1.0)
 */
public static float randomRSA(java.lang.Integer x) {    return (float) (x * Math.exp(seedRSA[0]) % seedRSA[1] / seedRSA[1]);
}

3.Java 隨機數產生器

Java自帶的隨機數(就是java.util.Random類),用過的都知道吧。那就直接上代碼:


/**
 * This is a method of Java random number generator.
 * 
 * @param x
 *            A seed for generator.
 * @return A float random value between [0.0,1.0)
 */
public static float randomJava(java.lang.Integer x) {    return (float) (new java.util.Random(1000 * x).nextDouble()); //乘1000來讓種子間差距增大
}

[1,0.71018493],[2,0.6234702],[3,0.900814],[4,0.80836606],[5,0.08570986],[6,0.9760623],[7,0.25340614],[8,0.16095819],[9,0.97060144],[10,0.8838867],[11,0.13829768],[12,0.045849733],[13,0.32319355],[14,0.23647882],[15,0.5138226] 平均時間:0-1ms
探索各種隨機函數(Java環境)
4.簡單的隨機數產生器

又是掃蕩Google的戰利品,很抱歉忘記出處惹……代碼:


/**
 * This is a method of basic random generator.
 * 
 * @param x
 *            A seed for generator.
 * @return A float random value between [0.0,1.0)
 */
public static float randomBasic(java.lang.Integer x) {
    x = (x << 13) ^ x;    return (float) Math
        .abs((1.0 - ((x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0));
}

[1,0.22637305],[2,0.2936329],[3,0.2571852],[4,0.5857607],[5,0.71294135],[6,0.31129658],[7,0.123062514],[8,0.8130556],[9,0.03246965],[10,0.92940825],[11,0.5371662],[12,0.7446079],[13,0.45132604],[14,0.11840015],[15,0.71875775] 平均時間:0-1ms
探索各種隨機函數(Java環境)

5.dotNet 隨機數產生器

寫了尼瑪整整一個類啊我擦,不過是源碼轉寫進來的,也沒費什麼力氣。代碼:


(DotNetRandom 類)

package com.awakening.code.random;/**
 * This is a random generator which translated from dotNet.
 * @Author:AwakeningCode
 * @Date: Created in 1:07 2018\1\16 0016
 */public class DotNetRandom {    private final static int MBIG = Integer.MAX_VALUE;    private final static int MSEED = 161803398;    private int inext, inextp;    private int[] SeedArray = new int[56];    public DotNetRandom() {        this((int) System.currentTimeMillis());
    }    public DotNetRandom(int Seed) {        int ii;        int mj, mk;

        mj = MSEED - Math.abs(Seed);
        SeedArray[55] = mj;
        mk = 1;        for (int i = 1; i < 55; i++) {            /*
             * Apparently the range [1..55] is special (Knuth) and so we're
             * wasting the 0'th position.
             */
            ii = (21 * i) % 55;
            SeedArray[ii] = mk;
            mk = mj - mk;            if (mk < 0)
                mk += MBIG;
            mj = SeedArray[ii];
        }        for (int k = 1; k < 5; k++) {            for (int i = 1; i < 56; i++) {
                SeedArray[i] -= SeedArray[1 + (i + 30) % 55];                if (SeedArray[i] < 0) SeedArray[i] += MBIG; } } inext = 0; inextp = 21; Seed = 1; } /** * Return a new random number [0,1) and reSeed the Seed array. * @return A double [0,1) */ protected double rand() { int retVal; int locINext = inext; int locINextp = inextp; if (++locINext >= 56)
        locINext = 1;        if (++locINextp >= 56)
            locINextp = 1;
        retVal = SeedArray[locINext] - SeedArray[locINextp];        if (retVal < 0)
            retVal += MBIG;
        SeedArray[locINext] = retVal;
        inext = locINext;
        inextp = locINextp;        /*
         * Including this division at the end gives us significantly improved
         * random number distribution.
         */
        return (retVal * (1.0 / MBIG));
    }
}package com.awakening.code.random;/**
 * @Author:AwakeningCode
 * @Date: Created in 1:08 2018\1\16 0016
 */public class TestDotNetRandom {    /**
     * This is a method of doNet random number generator.
     *
     * @param x
     *            A seed for generator.
     * @return A float random value between [0.0,1.0)
     */
    public static float randomDoNet(java.lang.Integer x) {        return (float) new DotNetRandom(1000 * x).rand();
    }    public static void main(String[] args) {        String[] Array = new String[16];        long add = 0;        for (int i = 1; i < 16 ; i++){            long startTime = System.currentTimeMillis();
            System.out.println("開始測試 randomWH() :Generate numbers(1D)");            float result = randomDoNet(i);
            System.out.println("本次測試結果:" + result);            long endTime = System.currentTimeMillis();            long usingTime = endTime - startTime;
            System.out.println("結束測試 randomWH() :測試結束,所用時間:" + usingTime + "ms");            add += usingTime;            Array[i] = i + "," + result;
        }        long average = add / 24;
        System.out.println("本次測試平均時間:" + average + "ms");

        System.out.print("[");        for (int i = 0; i < Array.length; i++){
            System.out.print("[" + Array[i] + "],");
        }
        System.out.print("]");
    }

}

[1,0.15155746],[2,0.57687163],[3,0.0021858374],[4,0.42750004],[5,0.8528142],[6,0.27812842],[7,0.7034426],[8,0.12875678],[9,0.55407095],[10,0.97938514],[11,0.40469936],[12,0.8300135],[13,0.25532773],[14,0.6806419],[15,0.10595611] 平時時間:0-1ms
探索各種隨機函數(Java環境)

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