How can I build my own randi function from scratch?

2 次查看（过去 30 天）
erica Emmanuel
erica Emmanuel 2021-4-17
评论： Walter Roberson 2021-4-17
I want to create a randi function from scratch on Matlab, can anyone please help me do this?
  3 个评论
显示 1更早的评论
David Hill
David Hill 2021-4-17
Use sponge function of SHA-3 hash to generate bit-stream to use in generating random integers of the desired range.
Walter Roberson
Walter Roberson 2021-4-17
Interesting, but SHA3 produced full numbers of bits, so it produces values 0 to 2^n-1. To produce random integers in the range A to B fairly, 2^n (number of values) would have to be divisible by (B-A+1). That can only happen if (B-A+1) is a power of 2.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Jan
Jan 2021-4-17
What exactly is "from scratch"? Which tools are included, which one are excluded? E.g. where do you want to take your random bits from? Is using rand() okay or do you need your own pseudo random number generator?
What is the desired precision? If you use rand() as source of bits, remember that it replies values from the open interval (0,1) with 53 bit precision. So you get 2^53-2 different values (2^53 excluding 0 and 1). This is 2 * 3 * 5 * 53 * 157 * 1613 * 2731 * 8191. So if you want your input to get a random number from 1 to 7, it is not trivial to find an algorithm, which allows a perfect equi-distribution. If the small bias is a problem, you need a smart approach. This is easier, if you produce the random bits by your own.

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by