CogSim: Integrate ML-based Library (LAGER) into Multi-Physics Simulation Code

Abstract

In LAGER, the Mesh and Simulation History Extract (MASHExtract) package has been used for extracting various types of data from Kull runs. The package itself was written in python and completely enmeshed in the Kull codebase, making it impossible to use with other simulations. Having a version that extends to the Ale3d codebase would necessitate a complete re-write of the package, including a conversion to the C++ language. Extending the MASHExtract package to Ale3d requires a level of simulation independence, much of which would come from handling user requests, data management, and exporting. However, there is still a section of code that would need to be able to handle extracting data from the target codebase. Because of the often insurmountable differences between simulation codebases, the MASHExtract package would need a specific layer to be implemented for each codebase that handles this process of collecting and organizing the requested data. Furthermore, different simulation codebases also have different requirements for various enhancements they rely on—user interface, multi processor distribution, gpu acceleration, etc—all of which would also need to be handled by this layer. In regards to Kull and Ale3d specifically, the Kull implementation (KullMASHExtract) will need to be wrapped in Python, and Ale3d (Ale3dMASHExtract) will need to be wrapped in RAJA. Since Kull is primarily wrapped in SWIG, we should also use this library for our own wrapping to maintain consistency. There are also differences between what metrics are available for extraction. In particular, Kull has a wide array of physics metrics that may not be available in Ale3d, and these differences will need to be accounted for when re-writing MASHExtract.