On 6/30/22, Ewout ter Hoeven <e.m.terhoe...@student.tudelft.nl> wrote: > A function to get the minimum and maximum values of an array simultaneously > could be very useful, from both a convenience and performance point of view. > Especially when arrays get larger the performance benefit could be > significant, and even more if the array doesn't fit in L2/L3 cache or even > memory. > > There are many cases where not either the minimum or the maximum of an array > is required, but both. Think of clipping an array, getting it's range, > checking for outliers, normalizing, making a plot like a histogram, etc. > > This function could be called aminmax() for example, and also be called like > ndarray.minmax(). It should return a tuple (min, max) with the minimum and > maximum values of the array, identical to calling (ndarray.min(), > ndarray.max()). > > With such a function, numpy.ptp() and the special cases of numpy.quantile(a, > q=[0,1]) and numpy.percentile(a, q=[0,100]) could also potentially be > speeded up, among others. > > Potentially argmin and argmax could get the same treatment, being called > argminmax(). > > There is also a very extensive post on Stack Overflow (a bit old already) > with discussion and benchmarks: > https://stackoverflow.com/questions/12200580/numpy-function-for-simultaneous-max-and-min
FYI, I have a fairly simple gufunc implementation of `minmax` in ufunclab (https://github.com/WarrenWeckesser/ufunclab), along with `arg_minmax`, `min_argmin` and `max_argmax`. See README.md starting here: https://github.com/WarrenWeckesser/ufunclab#minmax For those familiar with C and gufunc implementation details, you can find the implementations in https://github.com/WarrenWeckesser/ufunclab/blob/main/src/minmax/minmax_gufunc.c.src. You'll see that, as far as gufuncs go, these are not very sophisticated. They do not include implementations for all the NumPy data types, and I haven't yet spent much time on optimization. Warren > _______________________________________________ > NumPy-Discussion mailing list -- numpy-discussion@python.org > To unsubscribe send an email to numpy-discussion-le...@python.org > https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ > Member address: warren.weckes...@gmail.com > _______________________________________________ NumPy-Discussion mailing list -- numpy-discussion@python.org To unsubscribe send an email to numpy-discussion-le...@python.org https://mail.python.org/mailman3/lists/numpy-discussion.python.org/ Member address: arch...@mail-archive.com
