I am confused . Shouldn't rint round to nearest integer. http://en.cppreference.com/w/cpp/numeric/math/rint
Regards Mads On Jan 19, 2018 15:50, "Matthew Brett" <matthew.br...@gmail.com> wrote: > Hi Chuck, > > Thanks for the replies, they are very helpful. > > On Fri, Jan 19, 2018 at 1:51 PM, Charles R Harris > <charlesr.har...@gmail.com> wrote: > > > > > > On Fri, Jan 19, 2018 at 6:41 AM, Charles R Harris > > <charlesr.har...@gmail.com> wrote: > >> > >> > >> > >> On Fri, Jan 19, 2018 at 3:30 AM, Matthew Brett <matthew.br...@gmail.com > > > >> wrote: > >>> > >>> Hi, > >>> > >>> Sorry for my confusion, but I noticed (as a result of the discussion > >>> here [1]) that np.rint and the fallback C function [2] seem to round > >>> to even. But - my impression was that C rint, by default, rounds down > >>> [3]. Is numpy rint not behaving the same way as the GNU C library > >>> rint? > >>> > >>> In [4]: np.rint(np.arange(0.5, 11)) > >>> Out[4]: array([ 0., 2., 2., 4., 4., 6., 6., 8., 8., 10., 10.]) > >>> > >>> In [5]: np.round(np.arange(0.5, 11)) > >>> Out[5]: array([ 0., 2., 2., 4., 4., 6., 6., 8., 8., 10., 10.]) > >> > >> > >> The GNU C documentation says that rint "round(s) x to an integer value > >> according to the current rounding mode." The rounding mode is > determined by > >> settings in the FPU control word. Numpy runs with it set to round to > even, > >> although, IIRC, there is a bug on windows where the library is not > setting > >> those bits correctly. > > > > > > Round to even is also the Python default rounding mode. > > Do you mean that it is Python setting the FPU control word? Or do we > set it? Do you happen to know where that is in the source? I did a > quick grep just now without anything obvious. > > Cheers, > > Matthew > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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