Last Verified: 2023-12-19

NOTE IDL is not currently available on CORAL systems.


IDL (Interactive Data Language) is a product from NV5 Geospatial. IDL is a scientific programming language used across disciplines to extract meaningful visualizations from complex numerical data. With IDL you can interpret your data, expedite discoveries, and deliver powerful applications to market. IDL is the programming language of choice for many scientists and engineers because it’s easy to learn, easy to use, and requires fewer lines of code than other programming languages, making it easier and faster to go from data to discovery.

IDL at LLNL includes four licenses for the Advanced Math and Statistics (AMS) package, two on the OCF and two on the SCF networks. Note that IDL for Mac OS X does not support AMS or ISML.


Machines and Versions

See LC visualization software page.


Links to the latest version exist in /usr/tce/bin

Multiple versions may be accessible via modules. Type module avail idl to see the available options. You can specify a particular version in the module command, e.g., module load idl/8.8.3

The actual installation directories are in /usr/tce/packages/idl


The module load idl command will setup your PATH and any other needed environment variables.

You can also use the environment variable IDL_PATH to include personal files in IDL's search path. For more information about using this feature, see this help article: Quick tips for customizing your IDL program search path


IDL for UNIX can be used with one of two different interfaces. Starting IDL with the idl command begins a traditional IDL session using a simple text command line interface. If you are running the X window system, IDL can also be started with the idlde command, which invokes a convenient multiple-document interface called the IDL Development Environment.

To use the Advanced Math and Statistics (AMS) routines that are available with IDL Analyst, start up IDL in the manner shown above. Calling one of the IDL AMS routines will cause an IDL Analyst license to be checked out to you until you quit IDL. LC has two licenses for AMS on the OCF and two on the SCF.

Play nice with licenses!

1) Please do not hold onto IDL licenses overnight ("hoarding") unless you are actually using them -- hoarding licenses creates artificial scarcity and encourages further hoarding by others. It's a vicious circle.

2) If you are using multiple licenses, and we run out of licenses, please consider releasing one or two so that we are not out any more.

How to get "extra" "free" licenses An important quirk of IDL licensing is that IDL checks out only one license per node/DISPLAY, no matter how many instances of IDL you run on that node. This can be confirmed easily by running them by hand and checking the license server records. So if you get 16 CPUs on one node, each with 4 cores, you might be able to make good use of as many as 64 copies of IDL using only a single license! Please ask for more details.

Running without a license All IDL installations also include the IDL Virtual Machine. If all you need to do is run an IDL SAVE (.sav) file, you can run it with the IDL Virtual Machine instead, which requires no license at all! See the IDL Virtual Machine Applications documentation for more information.
You are encouraged to use the IDL Virtual Machine instead of the main IDL application whenever possible in order to free up licenses for other users.

Rendering Errors/Crashes

Most LC systems are not optimized for hardware rendering (with the exception of dedicated visualization clusters accessed via NICE DCV). If IDL consistently crashes with a "Segmentation fault" or "Fatal Error" message when rendering/updating a display window, you may need to explicitly configure IDL to use software rendering. This option can be set via the IDL command line (idl) using the following:

; to configure IDL to use software rendering:

; to check the current value:

You can also change this setting via the GUI (idlde) under Window > Preferences > IDL > Graphics.

A screenshot highlighting the location of the "software rendering" option in the IDL GUI.
Preferences screenshot


At the UNIX shell prompt, you can access the help documentation by typing idlhelp

A live online version of this documentation is available on NV5 Geospatial's documentation site. They also provide on-site and online training.

Help is available from the LC Hotline:, (925) 422-4531


You can install IDL on your local workstation. The software is available for Linux, Mac and Windows. The IDL Analyst and IMSL libraries are not available on OS X as of July 2012.

Only license administrators can download the IDL software from General LC users can download the installer from the CZ Confluence page. If you do not see the installer you are looking for, please contact


If you have an account on the LC platforms, you can use the LLNL LC site license to process data generated on Livermore Computing resources.

For IDL 8.6 and later

You can specify license information during installation or by running the L3Harris License Administrator. Please select "Use License Server" and enter the appropriate server information as seen below.

For the OCF:

  Port:  28521

For the SCF:

  Port:  28521
A screenshot of the L3Harris License Administrator showing a proper license server connection configuration.
License administrator screenshot

Offline Usage

Your desktop needs to be connected to the network to reach the license server. If you have a specific need to use your local IDL installation offline (e.g. on travel), licenses can be "borrowed" temporarily by selecting "Borrow Licenses from a Server" in the L3Harris License Administrator.

Again; Play nice with licenses! Please only "borrow" for offline use when absolutely necessary, and only for as long as you actually need. If you are done using a license and regain network access before the "Borrow time" expires, please "Return All Borrowed Licenses" so they are available for other users.

For older versions of IDL

LC no longer supports IDL versions 8.5.1 and older, as they use a different licensing system. Please migrate to IDL 8.6 or later for our site license to continue to work.