I like the idea ! On Mon, 08 Jun 2026 08:59:24 -0500 "Jeff Epler" <[email protected]> wrote:
> In a recently merged PR (https://github.com/python/cpython/pull/150555), > CPython has added a family of "*pi" functions to the math module, which take > half-turn arguments instead of radians. One reason these functions are > advantageous is that it's easy to provide the property that `sinpi(n/2)` is > exact for all integers n, while `sin(pi*n)` is never exactly equal to the > mathematical ideal except for n=0. > > These functions are recommended by IEEE754-2019 and standardized in C23 Annex > G. (note: I'm reading C23 draft revised 2023-01-24, not the final standard > document; and I do not have IEEE754-2019). > > C23 and CPython only added the real-valued versions of these functions, but > C23 "future library directions" notes that identifiers like `csinpi` are > "potentially reserved identifiers." > > Since CPython only requires C11, CPython includes implementations of these > functions for when the underling platform library does not provide it. These > implementations work by performing special case handling & range reduction, > followed by a call to the standard trig function with a scaled argument (in > the case of forward functions) or scaling of the result (in the case of > inverse/arc functions). > > I am interested in doing the numpy implementation, however I have never done > core numpy work before. If there is interest from the project, I would like > to initially offer a PR containing a single function such as `sinpi` and then > complete the others following numpy core developer feedback. > > Thanks, > Jeff > PS I notice via the archives that there are occasional "New Contributors' > Hour" meetings. Is the next one scheduled yet? -- Jérôme Kieffer tel +33 476 882 445 _______________________________________________ NumPy-Discussion mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/numpy-discussion.python.org Member address: [email protected]
