生成适合于Ruby的一个概率分布数值数组？ [英] Generate Array of Numbers that fit to a Probability Distribution in Ruby?

问题描述

说我有100条记录，我想模拟出的 created_at 更新，以便它的一些曲线拟合。有一个库来做到这一点，我也可以用什么公式？我认为这是沿着同样的轨迹：

Say I have 100 records, and I want to mock out the created_at date so it fits on some curve. Is there a library to do that, or what formula could I use? I think this is along the same track:

<一个href="http://stackoverflow.com/questions/3109670/generate-random-numbers-with-probabilistic-distribution">Generate随机数与概率分布

我不知道很多关于他们是如何划分的数学，但我正在寻找的东西，如：

I don't know much about how they are classified in mathematics, but I'm looking at things like:

• 钟形曲线
• 在对数（典型的生物/进化）曲线？ ...

• bell curve
• logarithmic (typical biology/evolution) curve? ...

只是为了寻找在code一些公式，所以我可以这样说：

Just looking for some formulas in code so I can say this:

• 有了100条记录， 1.week 的时间跨度，而 12.hours
• 设置 created_at 的每条记录，使得它适合，粗略来算，曲线

• Given 100 records, a timespan of 1.week, and an interval of 12.hours
• set created_at for each record such that it fits, roughly, to curve

太感谢了！

更新

我发现这个论坛的帖子关于Ruby算法的，这使我的 rsruby ，一个R / Ruby的桥梁，但是，似乎是太多了。

I found this forum post about ruby algorithms, which led me to rsruby, an R/Ruby bridge, but that seems like too much.

更新2

我写了这个小片段在试用 GSL 库，到那里......

I wrote this little snippet trying out the gsl library, getting there...

生成Rails中的测试数据，其中created_at沿下降的统计分布

推荐答案

您可以生成UNIX时间戳这是真的只是整数。首先要弄清楚的时候，你想创业，例如现在：

You can generate UNIX timestamps which are really just integers. First figure out when you want to start, for example now:

start = DateTime::now().to_time.to_i

了解，当你的间隔到底应该（比如1周后）：

Find out when the end of your interval should be (say 1 week later):

finish = (DateTime::now()+1.week).to_time.to_i

红宝石使用该算法生成随机数。这几乎是均匀的。然后生成两者之间的随机数：

Ruby uses this algorithm to generate random numbers. It is almost uniform. Then generate random numbers between the two:

r = Random.new.rand(start..finish)

然后再转换回日期：

Then convert that back to a date:

d = Time.at(r)

---

这看起来很有希望，以及： http://rb-gsl.rubyforge.org/files/rdoc/randist_rdoc.html

---

This looks promising as well: http://rb-gsl.rubyforge.org/files/rdoc/randist_rdoc.html

和这一点： http://rb-gsl.rubyforge.org/files/rdoc/rng_rdoc.html

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