Charles R Harris wrote: > > > On Tue, May 27, 2008 at 4:07 PM, Christopher Barker > <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: > > Charles R Harris wrote: > > > Yep, abs fails: > > > > In [1]: abs(array([-128,-128], dtype=int8)) > > Out[1]: array([-128, -128], dtype=int8) > > Well, yes, but this is a know vagary of the the hardware > implementation > for signed integers, as demonstrated by that JAVA Puzzles video > that Jon > Wright pointed us to a couple days ago. (Which to me could have been > titled: "Why I don't want to use JAVA") > > Sure, it could be fixed in this case by promoting to a larger > type, but > it's going to fail at the largest integer anyway, and I don't > think any > expects abs() to return a new type. > > > No, it could be completely fixed by promoting the output to the > corresponding unsigned type. It wouldn't even require much cleverness > in the ufunc. > > In [2]: abs(array([-128,-128], dtype=int8)).view(uint8) > Out[2]: array([128, 128], dtype=uint8)
Cool! More intersting bit information about 2's complement. -Travis _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion