Hello Nathaniel, It is hard to say what is normative practice with NumPy, because there are at least three paradigms:
(1) Some operations are implemented as methods of the `ndarray` class. `sum` and `mean` are examples. (2) Some operations are implemented via functions that invoke a private method of the class. `abs` is an example of this: In [8]: x= array([1+1J]) In [9]: x.__abs__() Out[9]: array([ 1.41421356]) (3) Some operations are implemented as functions that operate directly on the array, e.g., RMS (root-mean-square). Because calculating the square of the magnitude is such a widely-used operation, and is often done in a grossly inefficient manner (e.g., by taking the absolute value, which involves a square-root, and then squaring), I believe that there is a strong argument for doing either (1) or (2). I'd prefer (1). Phillip On Thu, Oct 8, 2015 at 3:05 PM, Nathaniel Smith <n...@pobox.com> wrote: > Hi Phillip, > > My advice would be to stick with the function call. It's consistent with > most other array operations (esp. when you consider that the vast majority > of operations on arrays are functions defined in third party libraries like > yours), and the more things we add to the core array object, the more work > it is for people implementing new array-style containers. I definitely > would not recommend subclassing ndarray for this purpose -- there are all > kinds of subtle problems that you'll run into that mean it's extremely > difficult to do well, and may well be impossible to do perfectly. > > Good luck, > -n > On Oct 5, 2015 21:08, "Phillip Feldman" <phillip.m.feld...@gmail.com> > wrote: > >> My apologies for the slow response; I was experiencing some technical >> problems with e-mail. >> >> In answer to Antoine's question, my main desire is for a numpy ndarray >> method, for the convenience, with a secondary goal being improved >> performance. >> >> I have added the function `magsq` to my library, but would like to access >> it as a method rather than as a function. I understand that I could create >> a class that inherits from NumPy and add a `magsq` method to that class, >> but this has a number of disadvantages. >> >> Phillip >> >> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> https://mail.scipy.org/mailman/listinfo/numpy-discussion >> >> > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > https://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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