Working group documents defining plans and priorities for 2005-2006.
Draft of a CIG proposal to provide a model archiving and querying facility.
At the short-term crustal dynamics workshop, one of the priorities that emerged was the need to compare output from physics codes for benchmark problems. Typically, the results are computed with different modeling codes (and output formats), different computational meshes, and different basis functions. We would like to compare computed fields at a specified set of points or metrics of those fields (e.g., norms, RMS misfit).
To provide this functionality, we require tools and methodologies with the following features:
We would like to develop an initial implementation of this infrastructure for two specific codes presently being used by the short-term crustal dynamics group - LithoMop and GeoFEST. This prototype should provide the basic functionality to permit comparisons between models (i.e., different codes, meshes, and/or basis functions) for the short-term crustal dynamics benchmarks.
We request from CIG:
Other CIG working groups will likely also need this tool/methodology for their benchmarking exercises. Furthermore, this facility will be useful in evaluating the efficiency of different element types and mesh resolutions, and in regression testing.
One of the major workflow bottlenecks when setting up finite-element models of large, crustal dynamics simulations is the process of transforming the output from mesh generation software into a form that the physics codes can handle. A related obstacle to simulating large problems is that the mesh generation software for these complex geophysical domains runs in serial, thereby limiting the size of problems that can be simulated. These problems are encountered in any parallel modeling code that requires an unstructured mesh, and the creation of a separate package for mesh importing, partitioning, and refinement would be of enormous benefit to all such codes. The availability of this package would remove the burden of performing these tasks from the modeling codes, greatly simplifying their structure and improving the speed of development. The LithoMop and EqSim finite-element codes (soon to be merged into PyLith) are examples of codes that would benefit greatly from this package, as the parallel versions will require meshes that are already partitioned and refined. Other codes, such as GeoFEST, could take advantage of the standardization of a mesh importing facility, even if they do not require partitioning and refinement capabilities.
In order to facilitate simulation of crustal dynamics problems in realistic geologic structure using a variety of mesh generation software and modeling codes, we need software infrastructure with the following features:
In defining the requirements of this package, we are assuming a minimal number of features in the mesh generation software used for the complex geologic structure in crustal dynamics. We assume that the mesh generation software provides nodal coordinates, element connectivities (nodes in each element), and groups of nodes and elements identifiable by some ID (integer or string). Some mesh generation software may offer additional abilities, such as the ability to provide groups of element faces, and it may be useful for the proposed package to take advantage of such features when available.
Some the of the functionality of this package (object for storing and handling mesh topology) appears to be already present in the Sieve software package under development by Dmitry Karpeev and Matt Knepley at ANL.
Summary of workflow in short-term crustal dynamics modeling. The different software packages are color coded according to the availability. The CIG effort is focused on the physics codes.
Slides from discussion of working group priorities for 2005-2007.