| Trouble with large FITS Table [message #7811] |
Sun, 12 January 1997 00:00 |
Murray Daniel Silvers
Messages: 1
Registered: January 1997
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Junior Member |
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Dear IDL experts,
I am having lots of trouble trying to read a 250 Meg FITS ASCII Table
Extension. When I try to use READFITS, I get the following error:
% READFITS: Now reading 1440 by 173044 array
% Unable to allocate memory: to make array.
Resource temporarily unavailable
This is on a Sun UltraSparc 1 machine with 256 Meg RAM and 455 Meg
swapspace (for virtual memory ... sounds like quite enough to me).
I can get the routine MRDFITS to work with limited success, by
specifying
a small fraction of rows to read. However, MRDFITS is quite slow, taking
minutes to read even single row:
fsc = mrdfits(datafile,1,head,range=[0,nrows]) ; read in nrows+1 of the
; ascii fits table extension
I think I could live with mrdfits if I could read in one column of the
entire file, and use that column as an index to figure out which rows I
need. Unfortunately, when I try to use the "columns" parameter, mrdfits
reads in the entire table (all columns) before trying to pass the
specified columns, and again I get the memory error.
FXBREAD could perhaps solve my problems, if it could operate on ASCII
tables rather than just on BINARY tables.
Anyone out there have any insight in how I could solve this problem?
Thanks,
Murray
--
========
Murray D. Silverstone UCLA Department of Physics &
Astronomy
Math Sciences 8105G
Email: murray@astro.ucla.edu 405 Hilgard Avenue
Los Angeles, CA 90095-1562
Phone: 310/825-3172 Fax: 310/206-2096 U.S.A.
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