Hi, On Wed, Jul 3, 2019 at 9:08 AM Charles R Harris <charlesr.har...@gmail.com> wrote: > > > > On Wed, Jul 3, 2019 at 9:08 AM Hameer Abbasi <einstein.edi...@gmail.com> > wrote: >> >> Hi, >> >> It turns out you're running into a bit-error. In general, the two's >> complement of -2 ** (n-1) with the bit-length being limited to n bits is >> itself... No way around that. And integers don't set hardware exceptions so >> checking for errors like these is hard as well. >> >> TL;DR: It's an error with how the integer is stored in memory and how you're >> running out of space. >> >> Regards, >> Hameer Abbasi > > > More like the eight bit twos complement of -128 is -128, bytes cannot > represent 128. Matlab used to (still does?) solve this problem by returning > 127 instead :) Basically, the data needs more precision. Returning an > unsigned type would lead to it's own problems with unexpected promotions when > the result was used. We could, I suppose, raise a warning, although that > might be considered noisy. If you use `absolute` instead, you can specify the > dtype.
I still think this is a major wart in numpy's abs. I'd really like to add a new function, `uabs` which would return an unsigned int for integer inputs. I'm happy to do a pull request if that also seems sensible to y'all, Cheers, Matthew _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@python.org https://mail.python.org/mailman/listinfo/numpy-discussion
