On Fri, Dec 31, 2021 at 5:46 AM Andras Deak <deak.and...@gmail.com> wrote:
> On Fri, Dec 31, 2021 at 1:36 AM Joseph Fox-Rabinovitz < > jfoxrabinov...@gmail.com> wrote: > >> Hi, >> >> I wrote a reference implementation for a C ufunc, `isint`, which returns >> True for integers and False for non-integers, found here: >> https://github.com/madphysicist/isint_ufunc. <snip> >> > > Shouldn't we keep the name of the stdlib float method? > > >>> (3.0).is_integer() > True > > See https://docs.python.org/3/library/stdtypes.html#float.is_integer > > This sounds obvious in hindsight. I renamed it to is_integer, including the repo itself. The new link is here: https://github.com/madphysicist/is_integer_ufunc > András > > > >> The idea came from a Stack Overflow question of mine, which has gotten a >> fair number of views and even some upvotes: >> https://stackoverflow.com/q/35042128/2988730. The current "recommended" >> solution is to use ``((x % 1) == 0)``. This is slower and more cumbersome >> because of the math operations and the temporary storage. My version >> returns a single array of booleans with no intermediaries, and is between 5 >> and 40 times faster, depending on the type and size of the input. >> >> If you are interested in taking a look, there is a suite of tests and a >> small benchmarking script that compares the ufunc against the modulo >> expression. The entire thing currently works with bit twiddling on an >> appropriately converted integer representation of the number. It assumes a >> standard IEEE754 representation for float16, float32, float64. The extended >> 80-bit float128 format gets some special treatment because of the explicit >> integer bit. Complex numbers are currently integers only if they are real >> and integral. Integer types (including bool) are always integers. Time and >> text raise TypeErrors, since their integerness is meaningless. >> >> If a consensus forms that this is something appropriate for numpy, I will >> need some pointers on how to package up C code properly. This was an >> opportunity for me to learn to write a basic ufunc. I am still a bit >> confused about where code like this would go, and how to harness numpy's >> code generation. I put comments in my .c and .h file showing how I would >> expect the generators to look, but I'm not sure where to plug something >> like that into numpy. It would also be nice to test on architectures that >> have something other than a 80-bit extended long double instead of a proper >> float128 quad-precision number. >> >> Please let me know your thoughts. >> >> Regards, >> >> - Joe >> _______________________________________________ >> 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: deak.and...@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: jfoxrabinov...@gmail.com >
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