On Wed, Mar 31, 2010 at 7:37 PM, Warren Weckesser <warren.weckes...@enthought.com> wrote: > T J wrote: >> On Wed, Mar 31, 2010 at 1:21 PM, Charles R Harris >> <charlesr.har...@gmail.com> wrote: >> >>> Looks like roundoff error. >>> >>> >> >> So this is "expected" behavior? >> >> In [1]: np.logaddexp2(-1.5849625007211563, -53.584962500721154) >> Out[1]: -1.5849625007211561 >> >> In [2]: np.logaddexp2(-0.5849625007211563, -53.584962500721154) >> Out[2]: nan >> > > Is any able to reproduce this? I don't get 'nan' in either 1.4.0 or > 2.0.0.dev8313 (32 bit Mac OSX). In an earlier email T J reported using > 1.5.0.dev8106.
>>> np.logaddexp2(-0.5849625007211563, -53.584962500721154) nan >>> np.logaddexp2(-1.5849625007211563, -53.584962500721154) -1.5849625007211561 >>> np.version.version '1.4.0' WindowsXP 32 Josef > > Warren > >> In [3]: np.log2(np.exp2(-0.5849625007211563) + np.exp2(-53.584962500721154)) >> Out[3]: -0.58496250072115608 >> >> Shouldn't the result at least behave nicely and just return the larger value? >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
