[Numpy-discussion] Question about numpy.random.choice with probabilties

[Robert Kern]

On Mon, Jan 23, 2017 at 9:22 AM, Anne Archibald <peridot.faceted at gmail.com>
wrote:
>
>
> On Mon, Jan 23, 2017 at 3:34 PM Robert Kern <robert.kern at gmail.com> wrote:
>>
>> I don't object to some Notes, but I would probably phrase it more like
we are providing the standard definition of the jargon term "sampling
without replacement" in the case of non-uniform probabilities. To my mind
(or more accurately, with my background), "replace=False" obviously picks
out the implemented procedure, and I would have been incredibly surprised
if it did anything else. If the option were named "unique=True", then I
would have needed some more documentation to let me know exactly how it was
implemented.
>
>
> It is what I would have expected too, but we have a concrete example of a
user who expected otherwise; where one user speaks up, there are probably
more who didn't (some of whom probably have code that's not doing what they
think it does). So for the cost of adding a Note, why not help some of them?

That's why I said I'm fine with adding a Note. I'm just suggesting a
re-wording so that the cautious language doesn't lead anyone who is
familiar with the jargon to think we're doing something ad hoc while still
providing the details for those who aren't so familiar.

> As for the standardness of the definition: I don't know, have you a
reference where it is defined? More natural to me would be to have a list
of items with integer multiplicities (as in: "cat" 3 times, "dog" 1 time).
I'm hesitant to claim ours is a standard definition unless it's in a
textbook somewhere. But I don't insist on my phrasing.

Textbook, I'm not so sure, but it is the *only* definition I've ever
encountered in the literature:

http://epubs.siam.org/doi/abs/10.1137/0209009
http://www.sciencedirect.com/science/article/pii/S002001900500298X

--
Robert Kern
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