[Numpy-discussion] old-Numeric: OverflowError on exp(-760) (original) (raw)

Sasha ndarray at mac.com
Mon Jun 12 18:15:15 EDT 2006

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 "", line 1, in ? OverflowError: math range error numpy.exp(760) inf math.exp(760) Traceback (most recent call last): File "", line 1, in ? OverflowError: math range error Numeric.exp(760) Traceback (most recent call last): File "", 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.maskedunaryoperation(Numeric.exp,0.0,MA.domaincheckinterval(-100,100)) exp(-760).filled() 0

You would need to replace -100,100 with the bounds appropriate for your system.

On 6/12/06, Sebastian Haase <haase at msg.ucsf.edu> 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 "", 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

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