爲什麼Random.setSeed xor參數與0x5DEECE66DL的Java實現？

Question

見http://docs.oracle.com/javase/7/docs/api/java/util/Random.html#setSeed(long)。代碼xors在減少mod 2^48之前使用乘數種子。爲什麼不減少傳遞的種子mod 2^48？ C當量的seed48不執行異或。

Answer 1

一個很好的閱讀，你可以在這裏找到：java.util.Random’s Magic Number 0x5DEECE66D。

和報價：

The analysis says it was chosen simply because researchers determined empirically 
that it produces a sequence of values satisfying various randomness tests 

這Document給人以魔術數量射門偏出。

還有一個報價：

我又試圖爲十進制值，不包括Java的搜索，發現 在一些課堂筆記答案：

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.