生成范围内的随机数 [英] Generate a Random Number within a Range

问题描述

我以前已经做过，但是现在我又在挣扎着，我认为我不理解问题背后的数学原理.

I have done this before, but now I'm struggling with it again, and I think I am not understanding the math underlying the issue.

我想在1任一侧的小范围内设置一个随机数.示例将是.98，1.02，.94，1.1等.我发现的所有示例都描述了在0和100之间获得随机数，但是如何使用它来获得我想要的范围?

I want to set a random number on within a small range on either side of 1. Examples would be .98, 1.02, .94, 1.1, etc. All of the examples I find describe getting a random number between 0 and 100, but how can I use that to get within the range I want?

尽管我使用的是Pure Data，但编程语言在这里并不重要.有人可以解释一下所涉及的数学吗?

The programming language doesn't really matter here, though I am using Pure Data. Could someone please explain the math involved?

推荐答案

制服

如果您希望在0.9到1.1之间(伪间隔)均匀分布(均匀分布)，则可以使用以下方法:

Uniform

If you want a (psuedo-)uniform distribution (evenly spaced) between 0.9 and 1.1 then the following will work:

  range = 0.2
  return 1-range/2+rand(100)*range/100

相应地调整范围.

如果您想要正态分布(钟形曲线)，则需要特殊的代码，该代码将特定于语言/库.您可以使用以下代码获得近似值:

If you wanted a normal distribution (bell curve) you would need special code, which would be language/library specific. You can get a close approximation with this code:

sd = 0.1
mean = 1
count = 10
sum = 0
for(int i=1; i<count; i++) 
  sum=sum+(rand(100)-50)
}
normal = sum / count
normal = normal*sd + mean

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