在需要重新设定种子之前，可以使用randomGenerator.nextDouble()多少次? [英] How many times can I use randomGenerator.nextDouble() before I need to reseed?

问题描述

我将Java中的Random类用作伪随机数生成器.我多次使用了nextDouble函数(〜10 ^ 5).我必须重新播种多少次才能防止获得相同的数字?是否需要播种?

I'm using the Random class in Java as a pseudo-random number generator. I'm using the function nextDouble a lot of times (~10^5). How many times before I have to reseed to prevent from getting the same numbers? Is reseeding needed?

    Random generator = new Random();
    double[] numbers = new double[n];
    for (int i = 0; i < n; i++) numbers[i] = generator.nextDouble();

这是一个实验，数字将用作空间上各个点的坐标，所以我希望分布尽可能均匀.

This is for an experiment, the numbers will be used as coordinates for points on a space, so I want the distribution to be as uniform as possible.

我该如何播种?我从哪里得到int种子?

Also how do I reseed? Where do I get the int seed from?

推荐答案

随机数生成器将从两个随机int值中生成一个随机double.内部种子具有48位，因此随机序列最多在2 ^ 48个int值或2 ^ 47个double值之后重复.

The random number generator will produce a random double from two random int values. The internal seed has 48 bit, so the random sequence repeats after at most 2^48 int values, or 2^47 double values.

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