George Marsaglia写了一个非常优秀的随机数生成器,它非常快、简单,并且周期比Mersenne Twister高得多。下面是代码和描述:
good C random number generator
我想将CMWC4096代码移植到Java,但它使用了几个无符号的数据类型,所以我不确定如何正确地做到这一点。下面是完整的C代码:
/* choose random initial c<809430660 and */
/* 4096 random 32-bit integers for Q[] */
static unsigned long Q[4096],c=362436;
unsigned long CMWC4096(void) {
unsigned long long t, a=18782LL;
static unsigned long i=4095;
unsigned long x,r=0xfffffffe;
i = (i+1) & 4095;
t = a*Q[i] + c;
c = (t>>32);
x = t + c;
if (x < c) {
x++;
c++;
}
return (Q[i] = r - x);
}
任何人都可以将其移植到Java吗?当你只有带符号的数字时,这是如何工作的?
编辑:感谢大家的快速回答!对于前一亿个数字,这段java代码似乎产生了与C代码相同的结果。它比Java的java.util.Random快3倍。
public class ComplimentaryMultiplyWithCarryRandom {
/**
* Choose 4096 random 32-bit integers
*/
private long[] Q;
/**
* choose random initial c<809430660
*/
private long c = 362436;
private int i;
public ComplimentaryMultiplyWithCarryRandom() {
Random r = new Random(1);
Q = new long[4096];
// TODO initialize with real random 32bit values
for (int i = 0; i < 4096; ++i) {
long v = r.nextInt();
v -= Integer.MIN_VALUE;
Q[i] = v;
}
i = 4095;
}
int next() {
i = (i + 1) & 4095;
long t = 18782 * Q[i] + c;
c = t >>> 32;
long x = (t + c) & 0xffffffffL;
if (x < c) {
++x;
++c;
}
long v = 0xfffffffeL - x;
Q[i] = v;
return (int) v;
}
}
https://stackoverflow.com/questions/397867
复制相似问题