Hi, I have been bitten by a subtlety in numpy scalar divisions. The next exposes the issue:
>>> -1/20 -1 >>> Numeric.array([-1])[0] / Numeric.array([20])[0] -1 >>> numarray.array([-1])[0] / numarray.array([20])[0] -1 >>> numpy.array([-1])[0] / numpy.array([20])[0] 0 After some digging, I've found that Python and C follow different conventions for doing this negative division: Python do a floor of the result, while C truncates it. As numpy scalar operations seems to be implemented in C, it seems that it follows the C convention and truncates the result. In fact, I like this behaviour of NumPy scalars (at least, when I'm aware of it!), but I thought it would be nice to warn other people about that. Cheers, -- >0,0< Francesc Altet http://www.carabos.com/ V V Cárabos Coop. V. Enjoy Data "-" ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
