Flexible implementation of multiphysics and discretizations in PyLith crustal deformation modeling software

Brad T. Aagaard, Charles A. Williams, & Matthew G. Knepley

Published August 24, 2016, SCEC Contribution #6927, 2016 SCEC Annual Meeting Poster #043

We are creating a flexible implementation of multiphysics and finite-element discretizations in PyLith, a community, open-source code (http://geodynamics.org/cig/software/pylith/) for modeling quasi-static and dynamic crustal deformation with an emphasis on earthquake faulting. The goals include expanding the current suite of elastic, viscoelastic, and elastoplastic bulk rheologies to include poroelasticity, thermoelasticity, and incompressible elasticity. We cast the governing equations in a form that involves the product of the finite-element basis function or its derivatives with pointwise functions that look very much like the strong form of the governing equation. This allows the finite-element integration to be decomposed into a routine for the numerical integration over cells and boundaries of the finite-element mesh and simple routines implementing the physics (pointwise functions). The finite-element integration routine works in any spatial dimension with an arbitrary number of physical fields (e.g., displacement, temperature, and fluid pressure). It also makes it much easier to optimize the finite-element integrations for proper vectorization, tiling, and other traversal optimization on multiple architectures (e.g., CUDA and OpenCL) independent of the pointwise functions. Users can easily extend the code by adding new routines for the pointwise functions to implement different rheologies and/or governing equations. Tight integration with the Portable, Extensible Toolkit for Scientific Computation (PETSc) provides support for a wide range of linear and nonlinear solvers and time-stepping algorithms so that a wide variety of governing equations can be solved efficiently.

Key Words
spontaneous rupture, multiphysics, computational geoscience

Citation
Aagaard, B. T., Williams, C. A., & Knepley, M. G. (2016, 08). Flexible implementation of multiphysics and discretizations in PyLith crustal deformation modeling software. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)