On Tue, Oct 11, 2011 at 2:51 PM, Matthew Brett <matthew.br...@gmail.com>wrote:
> Hi > > On Tue, Oct 11, 2011 at 3:16 PM, Charles R Harris > <charlesr.har...@gmail.com> wrote: > > > > > > On Tue, Oct 11, 2011 at 12:23 PM, Matthew Brett <matthew.br...@gmail.com > > > > wrote: > >> > >> Hi, > >> > >> I recently ran into this: > >> > >> In [68]: arr = np.array(-128, np.int8) > >> > >> In [69]: arr > >> Out[69]: array(-128, dtype=int8) > >> > >> In [70]: np.abs(arr) > >> Out[70]: -128 > >> > > > > This has come up for discussion before, but no consensus was ever > reached. > > One solution is for abs to return an unsigned type, but then combining > that > > with signed type of the same number of bits will cause both to be cast to > > higher precision. IIRC, matlab was said to return +127 as abs(-128), > which, > > if true, is quite curious. > > octave-3.2.3:1> a = int8([-128, 127]) > a = > > -128 127 > > octave-3.2.3:2> abs(a) > ans = > > 127 127 > > Matlab is the same. That is curious... > > See you, > > Matthew > Well, it _is_ only off by 0.78%. That should be good enough for government work, right? Ben Root
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