Multi-level concurrency in a framework for integrated loosely coupled plasma simulations

The increasing availability of large scale computing capabilities has accellerated the development of high-fidelity coupled simulations. Such simulations typically involve the integration of models that implement various aspects of the complex phenomena under investigation. Coupled simulations are playing an integral role in fields such as climate modeling, earth systems modeling, rocket simulations, computational chemistry, and many other computational fields. Model coupling provides scientists with systematic ways to virtually explore the physical, mathematical, and computational aspects of the problem. Novel and flexible frameworks that facilitate the integration of the disparate models into a holistic simulation are used to perform this research, while making efficient use of the available computational resources. In this paper, we present one such framework, the Integrated Plasma Simulator (IPS) developed as part of the Center for Simulation of Radio Frequency Wave Interactions with Magnetohydrodynamics (SWIM). The IPS framework focuses on maximizing the ability of simulation creators to flexibly construct loosely coupled component-based simulations, by providing services for execution coordination, resource management, data management, and inter-component communication. This paper focuses on the implementation of the services that support the four levels of concurrency, allowing for maximum efficiency in resource utilization, while hiding the complexity involved in such a scheme from the developers of IPS components.