参见 http://docs.oracle.com/javase/7/docs/api/java/util/Random.html#setSeed(long) .代码 xors 种子与乘数减少它 mod 2^48 之前。为什么不直接减少传递的种子 mod 2^48？ C 等效的 seed48 不执行异或。
最佳答案
您可以在这里找到一本不错的读物:java.util.Random’s Magic Number 0x5DEECE66D .
还有一段话:
The analysis says it was chosen simply because researchers determined empirically
that it produces a sequence of values satisfying various randomness tests
还有这个Document也给了魔术数字一个机会。
还有一个引用:
I then tried a search for the decimal value, excluding Java, and found the answer in some class notes:
http://nut.bu.edu/~youssef/py502/monte_carlo_supplement.ps http://www.inf.ethz.ch/personal/gaertner/texts/own_work/random_matrices.pdf
and in some computer documentation:
http://developer.apple.com/documentation/Darwin/Reference/ManPages/html/_rand48.3.html
The Youssef notes say:
... I can only say that 25214903917_LONG and 11_LONG have
apparently been chosen by passing a battery of such [meaning
Marsaglia's DIEHARD] tests.
... Even in the case of the 48-bit generators we are discussing
today, cas26 will generate them all in a month or two of CPU time
and then start to repeat.
关于java - 为什么 Random.setSeed 的 Java 实现将参数与 0x5DEECE66DL 异或？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14264196/