Albert Einstein first posed the idea of gravitational waves in his general theory of relativity just over a century ago. But until now, they had never been observed directly. For the first time, scientists with the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration (LSC) have observed ripples in the fabric of spacetime called gravitational waves.
The LIGO project employs many concepts that the Open Science Grid (OSG) promotes—resource sharing, aggregating opportunistic use across a variety of resources—and adds two twists: First, this experiment ran across LIGO Data Grid, OSG and Extreme Science and Engineering Discovery Environment (XSEDE)-based resources, all managed from a single HTCondor-based system to take advantage of both opportunistic and NSF eXtreme Digital (XD) allocations. Second, workflows analyzing LIGO detector data proved more data-intensive than many opportunistic OSG workflows. Despite these challenges, LIGO scientists were able to manage workflows with the same tools they use to run solely at Syracuse—Pegasus and HTCondor.
Peter Couvares, data analysis computing manager for the Advanced LIGO project at Caltech, specializes in distributed computing problems. He and colleagues James Clark (Georgia Tech) and Larne Pekowsky (Syracuse University) explained LIGO’s computing needs and environment: The main focus is on optimization of data analysis codes, where optimization is broadly defined to encompass the overall performance and efficiency of their computing. But while they use traditional optimization tasks to make things run faster, they also pursue more efficient resource management, and opportunistic resources—if there are computers available, they try to use them—thus the collaboration with OSG.
For further details: Open Science Grid