Abstract
The increasing availability of large scale computing
capabilities has accelerated 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,
fusion research, and many other computational fields. Model
coupling provides scientists with systematic ways to virtually
explore the physical, mathematical, and computational aspects
of the problem. Such exploration is rarely done using a single
execution of a simulation, but rather by aggregating the results
from many simulation runs that, together, serve to bring to
light novel knowledge about the system under investigation.
Furthermore, it is often the case (particularly in engineering
disciplines) that the study of the underlying system takes the
form of an optimization regime, where the control parameter
space is explored to optimize an objective functions that captures
system realizability, cost, performance, or a combination thereof.
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 describe
the integration of the DAKOTA optimization and parameter
sweep toolkit with the Integrated Plasma Simulator (IPS), a
component-based framework for loosely coupled simulations.
The integration allows DAKOTA to exploit the internal task
and resource management of the IPS to dynamically instantiate
simulation instances within a single IPS instance, allowing for
greater control over the trade-off between efficiency of resource
utilization and time to completion. We present a case study
showing the use of the combined DAKOTA-IPS system to aid
in the design of a lithium ion battery (LIB) cell, by studying a
coupled system involving the electrochemistry and ion transport
at the lower length scales and thermal energy transport at the
device scales. The DAKOTA-IPS system provides a flexible tool
for use in optimization and parameter sweep studies involving
loosely coupled simulations that is suitable for use in situations
where changes to the constituent components in the coupled
simulation are impractical due to intellectual property or code
heritage issues.
