comp.lang.idl-pvwave archive - RDF feed
type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: Trouble with large FITS Table

Trouble with large FITS Table
type: item
description: 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.
creator: Murray Daniel Silvers
date: 1997-01-12T08:00:00-00:00