Ganga: a tool for computational-task management and easy access to Grid resources

We present the computational task-management tool Ganga, which allows for the specification, submission, bookkeeping and post processing of computational tasks on a wide set of distributed resources. Ganga effectively provides a homogeneous environment for processing data on heterogeneous resources. We give examples from High Energy Physics, demonstrating how an analysis can be developed on a local system and then transparently moved to a Grid system for processing of all available data. Ganga has an API that can be used via an interactive interface, in scripts, or through a GUI. Specific knowledge about types of tasks or computational resources is provided at run-time through a plugin system, making new developments easy to integrate. We give an overview of the Ganga architecture, give examples of current use, and demonstrate how Ganga can be used in many different areas of science.