PHP的随机播放功能随机性如何? [英] How random is PHP's shuffle function?

问题描述

有人知道PHP shuffle()函数的随机性是什么吗?是否取决于操作系统? 它使用PHP自己的播种器吗?

Does anyone know what's the randomness of PHP's shuffle() function? Does it depend on the operating system? Does it use PHP's own seeder?

是否可以使用mt_rand()作为生成器?

Is it possible to use mt_rand() as generator?

推荐答案

shuffle()函数基于与rand()相同的生成器，后者是基于

shuffle() function is based on the same generator as rand(), which is the system generator based on linear congruential algorithm. This is a fast generator, but with more or less randomness. Since PHP 4.2.0, the random generator is seeded automatically, but you can use srand() function to seed it if you want.

mtrand()基于 Mersenne Twister算法，它是最好的伪代码之一.可用的随机算法.要使用该生成器对数组进行混洗，您需要编写自己的混洗函数.例如，您可以查看 Fisher-Yates算法.编写自己的随机播放功能会产生更好的随机性，但会比内置随机播放功能慢.

mtrand() is based on Mersenne Twister algorithm, which is one of the best pseudo-random algorithms available. To shuffle an array using that generator, you'd need to write you own shuffle function. You can look for example at Fisher-Yates algorithm. Writing you own shuffle function will yield to better randomness, but will be slower than the builtin shuffle function.

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