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SIENews

The newsletter of the SIE de Investigación y Enseñanza N. 45 - March/April 2013

IDL usage statistics

About a couple of months ago we started collecting data about usage of licensed software packages, specifically IDL, the Intel and PGI compilers, and the NAG library. Every ten minutes we connect to the IDL license server to obtain data on how many licenses are checked out by what users. The results for the months of February and March 2013 are shown in the figure below.
IDL statistics
Total users is the number of users who have run IDL in a given day.

Of course we cannot tell whether an open IDL session is active (program running, code development, etc.), or just idle (user forgot to close it). Nor the statistic includes those users running IDL on their laptop with a node-locked license.
The format of the license logfiles for the Intel and PGI compilers, as well as for NAG, is more complicated and difficult to parse, and the statistics will (likely) be presented in the next issue of SIENews.

Astropy installed (and warning on duplicated packages)

We have recently installed the Astropy python package in our Linux desktops. Current version is 0.2.1. Astropy is "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages". Note that for the time being several python modules are present both in their standalone version and in the astropy version, so you must take care to load the correct one. For instance, to work with fits files you can either use pyfits (import pyfits) or astropy (from astropy.io import fits). The same consideration applies for the package dealing with the World Coordinates System, where you can import pywcs or from astropy import wcs. For more detailed info about astropy please read the excellent Astropy documentation.

Useful Mac OS X commands

If you are using an iMac or a Mac laptop, and would like to access the scratch directory of a Linux machine, your home or perhaps burdeos, you can take advantage of samba from the command line (you must of course be connected to the internal network). I myself (ncaon) have defined the following aliases, which you can modify to your needs:
alias burdeos='mkdir -p /Users/ncaon/burdeos ; mount_smbfs //ncaon@burdeos:/scratch /Users/ncaon/burdeos'
alias homelinux='mkdir -p /Users/ncaon/homelinux ; mount_smbfs //ncaon@nas2:/home/ncaon /Users/ncaon/homelinux'
alias italia_scratch='mkdir -p /Users/ncaon/italia_scratch ; mount_smbfs //ncaon@italia:/scratch /Users/ncaon/italia_scratch'
All these aliases should go in file .bash_profile.

Another neat trick is having sudo recognize your environment and your aliases - by default it doesn't. To achieve that, simply create the following alias for sudo itself:
alias sudo='sudo ' (with the trailing space)
The reason why this trick works is explained in http://www.shellperson.net/using-sudo-with-an-alias/ and http://askubuntu.com/questions/22037/aliases-not-available-when-using-sudo (among many other websites).

Astrometry.net

We have installed IAC-wide version 0.43 of astrometry.net, available to all Linux users, complete with all the data index files. To run it, type for instance /usr/pkg/astrometry.net/astrometry.net-0.43/bin/solve-field (you may wish to define aliases for the commands you use most). There seem to be some issues with the fits2fits.py script which filters fits file. You can avoid filtering by adding the --no-fits2fits flag to the command line.

IRAF 64-bit issues

The default version of IRAF installed in our Fedora 17 Linux desktops is v2.16, 64-bit. While overall it works very well, and solves some long-standing problems (such as limits on how many files can be processed with tasks like imcombine), some issues have been reported, especially when using some external packages and with graphics task. For instance, task ellipse is unable to display interactively the fitted ellipses, or rvsao.xcsao gets stuck when interacting with the graphical window. If you experience similar issues, try to start IRAF in 32-bit, using the ecl216_32 command (no need to rerun mkiraf).
Also, if you get misterious "segmentation fault" error messages even when using quite inoffensive tasks (imdel for instance), just rerun mkiraf, which fixes a bug related to the definition of the "cache" variable.
SIE de Investigación y Enseñanza :: N. 45 - March/April 2013 - Contact: