Hi, Thanks for the reply. Just for general enjoyment: I found a solution: It seems that substituting N.exp(-700) by N.e ** -700 changes the behaviour to the better ...
Thanks, Sebastian Haase On Monday 12 June 2006 15:19, Sasha wrote: > BTW, here is the relevant explanation from mathmodule.c: > > /* ANSI C generally requires libm functions to set ERANGE > * on overflow, but also generally *allows* them to set > * ERANGE on underflow too. There's no consistency about > * the latter across platforms. > * Alas, C99 never requires that errno be set. > * Here we suppress the underflow errors (libm functions > * should return a zero on underflow, and +- HUGE_VAL on > * overflow, so testing the result for zero suffices to > * distinguish the cases). > */ > > On 6/12/06, Sasha <[EMAIL PROTECTED]> wrote: > > I don't know about numarray, but the difference between Numeric and > > python math module stems from the fact that the math module ignores > > errno set by C library and only checks for infinity. Numeric relies > > > > on errno exclusively, numpy ignores errors by default: > > >>> import numpy,math,Numeric > > >>> numpy.exp(-760) > > > > 0.0 > > > > >>> math.exp(-760) > > > > 0.0 > > > > >>> Numeric.exp(-760) > > > > Traceback (most recent call last): > > File "<stdin>", line 1, in ? > > OverflowError: math range error > > > > >>> numpy.exp(760) > > > > inf > > > > >>> math.exp(760) > > > > Traceback (most recent call last): > > File "<stdin>", line 1, in ? > > OverflowError: math range error > > > > >>> Numeric.exp(760) > > > > Traceback (most recent call last): > > File "<stdin>", line 1, in ? > > OverflowError: math range error > > > > I would say it's a bug in Numeric, so you are out of luck. > > > > Unfortunalely, even MA.exp(-760) does not work, but this is easy to fix: > > >>> exp = > > >>> MA.masked_unary_operation(Numeric.exp,0.0,MA.domain_check_interval(-1 > > >>>00,100)) exp(-760).filled() > > > > 0 > > > > You would need to replace -100,100 with the bounds appropriate for your > > system. > > > > On 6/12/06, Sebastian Haase <[EMAIL PROTECTED]> wrote: > > > Hi, > > > I'm using Konrad Hinsen's LeastSquares.leastSquaresFit for a convenient > > > way to do a non linear minimization. It uses the "old" Numeric module. > > > But since I upgraded to Numeric 24.2 I get OverflowErrors that I > > > tracked down to > > > > > > >>> Numeric.exp(-760.) > > > > > > Traceback (most recent call last): > > > File "<input>", line 1, in ? > > > OverflowError: math range error > > > > > > >From numarray I'm used to getting this: > > > >>> na.exp(-760) > > > > > > 0.0 > > > > > > Mostly I'm confused because my code worked before I upgraded to version > > > 24.2. > > > > > > Thanks for any hints on how I could revive my code... > > > -Sebastian Haase _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
