[Numpy-discussion] Proposal to add `weights` to `np.percentile` and `np.median`

Joseph Fox-Rabinovitz jfoxrabinovitz at gmail.com
Tue Feb 16 13:41:30 EST 2016


Thanks for pointing me to that. I had something a bit different in
mind but that definitely looks like a good start.

On Tue, Feb 16, 2016 at 1:32 PM, Antony Lee <antony.lee at berkeley.edu> wrote:
> See earlier discussion here: https://github.com/numpy/numpy/issues/6326
> Basically, naïvely sorting may be faster than a not-so-optimized version of
> quickselect.
>
> Antony
>
> 2016-02-15 21:49 GMT-08:00 Joseph Fox-Rabinovitz <jfoxrabinovitz at gmail.com>:
>>
>> I would like to add a `weights` keyword to `np.partition`,
>> `np.percentile` and `np.median`. My reason for doing so is to to allow
>> `np.histogram` to process automatic bin selection with weights.
>> Currently, weights are not supported for the automatic bin selection
>> and would be difficult to support in `auto` mode without having
>> `np.percentile` support a `weights` keyword. I suspect that there are
>> many other uses for such a feature.
>>
>> I have taken a preliminary look at the C implementation of the
>> partition functions that are the basis for `partition`, `median` and
>> `percentile`. I think that it would be possible to add versions (or
>> just extend the functionality of existing ones) that check the ratio
>> of the weights below the partition point to the total sum of the
>> weights instead of just counting elements.
>>
>> One of the main advantages of such an implementation is that it would
>> allow any real weights to be handled correctly, not just integers.
>> Complex weights would not be supported.
>>
>> The purpose of this email is to see if anybody objects, has ideas or
>> cares at all about this proposal before I spend a significant amount
>> of time working on it. For example, did I miss any functions in my
>> list?
>>
>> Regards,
>>
>>     -Joe
>> _______________________________________________
>> NumPy-Discussion mailing list
>> NumPy-Discussion at scipy.org
>> https://mail.scipy.org/mailman/listinfo/numpy-discussion
>
>
>
> _______________________________________________
> NumPy-Discussion mailing list
> NumPy-Discussion at scipy.org
> https://mail.scipy.org/mailman/listinfo/numpy-discussion
>



More information about the NumPy-Discussion mailing list