2d array slicing problem

Robert Kern robert.kern at gmail.com
Fri Oct 7 20:42:18 CEST 2005

jeg wrote:
> dear all,
> i'm an astronomer working with 2d images -- 2d numarrays. i have a
> script which basically does some operations on some images, and one of
> the first steps is to find a galaxy on an image (at, say, a known x,y
> coord), and create a sub-image by slicing out part of the larger array
> to create a more managable smaller one (e.g. 50x50 pixels from a
> 1000x1000 array).
> i was running this fine under python 2.3.4, but due to the slowness of
> my machine, moved to a speedy 64-bit linux box running version 2.4.2.
> arrays were no longer being sliced in the correct way, for example:
> B = A[3:7,6:10]
> generates different Bs if i run an identical script on the same image
> on the different machines.
> note: we deal with FITS format images, which are read into numarrays
> using the pyfits.py module. does anyone know any obvious reason this
> should be happening? 

Not without having the data and the machines in front of me. You'll get
better luck asking on numarray's mailing list.

Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter

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