[AstroPy] reading one line from many small fits files
Tue Jul 31 11:32:22 CDT 2012
On 07/31/2012 12:13 PM, Derek Homeier wrote:
> indeed the question was about tables, I just still had the discussion about automatic
> scaling and the potential type conversion coming with it in mind. And the docs mention
> `FITS_rec` is the data part of a table HDU's data part. This is a
> layer over the `recarray`, so we can deal with scaled columns.
> so I was wondering if some automatic scaling features might have been added
> (or be in testing) in 3.1 svn.
PyFITS has had scaling of table columns with TSCAL and TZERO for a long
time--to my knowledge nothing has changed there. (For what it's worth,
the in-progress changelog for 3.1 can be viewed here:
Are you saying there is a noticeable performance degradation from a
previous version of PyFITS? What version were you using before?
There was at one time a severe performance issue with tables containing
string columns, but that should be fixed. It's possible there is another?
Though I will say that row-based access in PyFITS has always been rather
inefficient--it was originally designed for more efficient column
access. Though this is an artifact of using Numpy's recarray class in
the background. There are plans to eventually replace this with the
Astropy package's Table implementation.
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