Node.js中的分布抽样 [英] distributional sampling in Node.js

问题描述

我想知道如何在Node.js中执行分布抽样。

I wonder how it's possible to perform distributional sampling in Node.js.

特别是，我有元素数量，其中元素的第i个值数组是第i个元素的概率，例如，

In particular, I have the number of elements, where the i'th value of the arrays is the probability of the element i'th, like following

[0.2 0.3 0.5]

现在我需要执行采样，并且一半样本的采样结果应为0.2的样本中的2为0，在0.3个样本中是1。

Now I need to perform sampling, and the result of the sampling in half of the samples should be 2 in 0.2 of the samples is 0 and in 0.3 of the samples is 1.

推荐答案

传统方法：

function distribute(probs) {
    return function() {
        var r = Math.random();
        var i = 0,
            acc = 0;
        while ((acc += probs[i]) <= r)
            i++;
        return i;
    };
}
var sample = distribute([0.2, 0.3, 0.5]);
sample();
sample();
sample();
…

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