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Yale Astronomy

Interactive Data Language (IDL)

IDL Resources >> Helpful Tips

Information on IDL Licenses

Hi Folks,

Here's some information on how IDL licenses work and how to best utilize them. This info is mainly of use to people who may invoke more than 1 IDL session, eg running multiple CPU intensive jobs, logging in from home or the observatory, etc.

There are a few different types of IDL licenses: node-locked, and floating. Node-locked licenses are fixed to a specific host computer. However, In our research lab we have floating licenses which can be shared by many computers and many users. We intentionally bought an expensive multi-user license since so many of us use IDL on a daily basis.

This multi-user license allows a fixed number if IDL "Sessions" to be going simultaneously. I think we are allowed 10 "sessions." This is so many sessions that it is rare than all will be in use at any one time. But since all of us use IDL, and many of us are putting our labs 14 CPU's to work with intensive calculations, it is helpful to know how to avoid using up all the licenses. (When all licenses are used IDL drops you into 7-minute demo mode. This is ok for plotting a quick graph or a calculation but is unacceptable for real research work.)

The key thing to know is IDL's definition of a "Session". Each session takes up 1 of the 10 IDL licenses so, if we have too many sessions going at once we'll run out of licenses. A "Session" is defined as an instance of IDL running on one computer ON A SEPARATE X-window client. Here are some examples of what this means:

  • Running IDL on 2 computers (eg. tauceti and estrella): 2 licenses
  • Running 2 IDL jobs on one computer (eg. tauceti) with X windows display on tauceti:0.0 : 1 license
  • Running 5 IDL jobs on one computer (eg. tauceti) with X windows display on tauceti:0.0 : 1 license !!!! (that's cool)
  • Running 5 IDL jobs on one computer (eg. tauceti) with *ALL* X windows display on another comp (eg. eclipse:0.0 or estrella:0.0): 1 license
  • Running 2 IDL jobs on one computer (eg. tauceti), with 1 X window display on tauceti, and 1 Xwindow display on another comp. (eg. eclipse): 2 licenses

The latter point also implies that if you are logged in at home (or observatory) AND logged in at school, you will, in general use 2 IDL licenses even if you are logged onto only one computer. I *think* you can avoid this by changing your X windows graphics display, eg from your home computer type: setenv DISPLAY eclipse.sfsu.edu:0.0 . Of course this won't let you display x graphics at home.

If IDL licenses run out:

  • Think if you are running IDL on more than one computer (did you forget to log out somewhere?)
  • Think if you are displaying IDL on more than 1 X display. Example: 2 IDL jobs running on arwen with displays set to arwen.sfsu.edu:0.0 AND shane.ucolick.org:0.0 = 2 IDL licenses used up.
  • If you are in the lab, ask other if they can start up a new IDL session. If not, ask if they have an extra session going which they can close.

How to kill an IDL job:

If you are at the window in which IDL is running, just type:

IDL> exit

If you are logged on remotely, and want to kill one of your jobs, type either:

ps -ef | grep idl
ps aux | grep idl

You will see something like:

chris    1170    0.0   0.0    8860    8 std   R+    12:05PM    0:00.00 grep idl

One of the 1st 2 numbers after your name is the job ID #. End your IDL job:

kill -9 1170


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