[Numpy-discussion] f.p. powers and masked arrays (original) (raw)

Michael Fitzgerald mpfitz at calmail.berkeley.edu
Fri Jun 23 17:15:58 EDT 2006

Ping!

Is anyone else seeing this? It should be easy to test. If so, I
think it's a bug.

Best, Mike

On Jun 21, 2006, at 9:39 PM, Michael Fitzgerald wrote:

Hello all, I'm encountering some (relatively new?) behavior with masked arrays that strikes me as bizarre. Raising zero to a floating-point value is triggering a mask to be set, even though the result should be well-defined. When using fixed-point integers for powers, everything works as expected. I'm seeing this with both numarray and numpy. Take the case of 0**1, illustrated below:

import numarray as n1 import numarray.ma as n1ma n1.array(0.)**1 array(0.0) n1.array(0.)**1. array(0.0) n1ma.array(0.)**1 array(0.0) n1ma.array(0.)**1. array(data = [1.0000000200408773e+20], mask = 1, fillvalue=[ 1.00000002e+20]) import numpy as n2 import numpy.core.ma as n2ma n2.array(0.)**1 array(0.0) n2.array(0.)**1. array(0.0) n2ma.array(0.)**1 array(0.0) n2ma.array(0.)**1. array(data = 1e+20, mask = True, fillvalue=1e+20) I've been using python v2.3.5 & v.2.4.3, numarray v1.5.1, and numpy v0.9.8, and tested this on an x86 Debian box and a PPC OSX box. It may be the case that this issue has manifested in the past several months, as it's causing a new problem with some of my older code. Any thoughts? Thanks in advance, Mike All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel? cmd=lnk&kid=107521&bid=248729&dat=121642

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