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Project Description

The LIGO Data Analysis System - (LDAS) is the LIGO Laboratory's integrated software/hardware data analysis system for analyzing and processing of LIGO Frame data downstream of the generation of the archival Frame files. The system is based on a collection of distributed processes that are centrally controlled to carry out complex tasks across multiple compute servers by flow control known as a pipeline job. The distributed nature of the processes involved in the pipeline allows for concurrency ( typically on the order of 30 pipelines) within a given LDAS system. The flexibility of the distributed processes allows for many distinct flavors of pipeline jobs to be carried out within LDAS. Here is just a few examples of the classes of pipeline jobs available (details here):

The LIGO Laboratory operated nearly a dozen LDAS systems. The principle systems available for use by the LIGO Scientific Collaboration are located at Caltech and the two observatories. These system can be monitored by simply pointing a web browser at the home page's of the LDAS systems and following the links to the current jobs, API logs, statistics and other monitoring pages. The links for these four primary LDAS web sites are:

In addition, the LDAS development team operates seven other LDAS systems at Caltech for development and testing purposes. The one most closely matching the hardware configurations of the systems above is:

NOTE: It is possible to move around from one LDAS system to another simply by clicking on the map of the lower 48 States located at the top of any LDAS home page.

Project Contacts

  Kent Blackburn (blackburn_k at ligo dot caltech dot edu): Architect
  Stuart Anderson (anderson at ligo dot caltech dot edu): System Administration
  Ed Maros (emaros at ligo dot caltech dot edu): Librarian


Official Releases

The latest official release of LDAS is version 1.7.0, released on July 27th, 2005 by LIGO's LDAS development team at the California Institute of Technology. A list of changes since the version 1.6.0 release can be found at the following website. Downloads of this release are available in two formats:

In order to run and operate an LDAS system, you will also need the LDCG tool suite and LAL/LALwrapper. These packages can be mirrored along with the binary distribution of LDAS over the internet, or if one prefers, it can be built using the official "how-to" document found at the LDAS website.

To fully utilize a running LDAS system requires the installation of IBM's DB2 database server. This database is available under an academic licensing agreement for teaching and research known as the IBM Sholars Program at no charge. Once you have acquired the necessary licensing from IBM, you will find instructions for installing and using the DB2 database on the LDAS website.

LDAS is a large complex software system designed to run on a large distributed network of servers and PC clusters. However, due to the shared object technologies used by LDAS processes, it is quite possible to run LDAS on single computer whether it be a desktop or even a laptop. In fact, the performance of LDAS runing on a single computer is quite remarkable when the types of requests and the rate at which requests are being made does not place a huge demand on the single computer's memory resources. A custom "how-to" documenting the procedure for setting up LDAS on a single computer is available at the LDAS websites for those interested in running a mini-LDAS at home. It is recommended that this be installed on a single computer with a clock speed of at least 2GHz and at least 1GB of memory for best results.


There are a number of subpackages that contain complete self contained subsets of the full LDAS software distribution (Excluding needed LDCG Software!).

These are only available as tarball distributions of the source code. Documentation for how to get and install these subpackages, along with their dependencies on LDCG tools, can be found at the following website.

Development Snapshots

The LDAS development system website posts nightly builds of tarball distributions of the development code base that is current in CVS as of 7:00 PM Pacific Time. The snapshots remain available for up to ten days before they are deleted in favor of newer snapshots. There is no guarantee that any of these development snapshots are public use, but they are made available for those interested in participating in LDAS development or have a need for functionality on present in the devlopment code. No support for these snapshots is intended.

The development snapshots of LDAS require the development version of the LDCG tools. This version of LDCG is experimental and not available for mirroring over the internet. Instructions for how to build the development version of LDCG can be found in the LDAS development "how-to" document.

Testing and Quality Assurance

Unit, Integration & System Testing

The LDAS Software Development Team routinely carries out unit(component level), integration(program interface level) and system(user interface level) testing of the LDAS Software System. Results from these tests are available on the web at the following links:

Using the controlMonitorAPI, it is also possible to perform many of the system level tests in a one-shot mode from the client's GUI. Under the LDAS Test menu are sample user commands to exercise each user command. It is also possible for the experienced user to make edits to the existing scripts to carryout user defined commands. Results of these system tests are reported back to the controlMonitorAPI's client once the test job completes. For more information, see the Using controlMonitorAPI Client webpage found off of any LDAS homepage.

Quality Assurance

The LIGO Development Team has conducted a series of mock data challenges in collaboration with the LIGO Scientific Collaboration. The details of these MDCs are captured in technical documents that can be found in the LIGO Document Control Center:

These MDCs provided many of the integration and system level test scripts that are used in the LDAS test procedures. As a result of these efforts the LDAS Development Team was able to work closely with the LIGO Scientific Collaboration to assure that the software and hardware platforms of LDAS meet the quality assurance needs of the community.

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Open Tasks

Next Relese

Here is a list of tasks that are scheduled to go into the next release of LDAS.

Long Term