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 <jfoxrabinov...@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@scipy.org > https://mail.scipy.org/mailman/listinfo/numpy-discussion >
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