Geodynamics - Resources: PyLith: About

Published on

26 Oct 2021

Description

PyLith is a finite-element code for dynamic and quasistatic simulations of crustal deformation, primarily earthquakes and volcanoes.

Binary packages are available for macOS and Linux. Detailed installation instructions for the binary packages are in the PyLith manual. Use the PyLith Installer to install from source. We also offer a Docker image (see the PyLith Install Manual for instructions) for development or running PyLith within a portable, virtual Linux environment. Windows 10 users should install the Windows Subsystem for Linux and use the Linux x86_64 binary.

Release Notes

PyLith 4.0 adds output of changes in fault tractions for prescribed slip, orientation information for faults and boundary conditions, and initial guesses for the solution based on proper orthogonal decomposition. Refer to PyLith v4.0.0 release notes for more information.

PyLith 3.0 includes major changes to the underlying finite-element formulation and implementation in order to support a more flexible specification of the governing equations and higher order basis functions. These changes affect how simulations are defined. Parameter files for previous versions will need to be updated; the changes are too complex for a simple translation table. Some features present in v2.2.2, such as spontaneous rupture and finite strain, have not yet been implemented in the new formulation.

Features

Multiphysics
- Elasticity for linear isotropic materials and linear Maxwell, generalized Maxwell, and power law viscoelastic models
- Incompressible elasticity for linear isotropic materials
- Prescribed slip for quasistatic and dynamic simulations
Higher order basis functions
Allow user to select order of basis functions independent of the mesh (which defines the geometry). This permits higher resolution for a given mesh.
Switch to using PETSc time-stepping (TS) algorithms
Replace simple Python-based time-stepping implementations with PETSc time-stepping algorithms that provide support for higher order discretization in time and real adaptive time stepping.
Static Green's functions with user-specified discretization of fault slip impulses
Import finite-element meshes from Cubit (Exodus II), Gmsh, and LaGriT
Modular approach for initial conditions
Output of subfields with user-defined basis order
Simulation metadata with command line utility for searching metadata
Convert to Python 3
Convert LaTeX documentation to Sphinx + MyST
Testing with the Method of Manufactured Solutions
New suite of examples, including examples using incompressible elasticity and poroelasticity
Automatically assign label value for fault cohesive cells (id setting is obsolete).
Use description for descriptive labels and label and label_value for tagging entities. PyLith's use oflabel and label_value now corresponds to PETSc labels and label values.

Features no longer supported

We have removed support for reading LaGriT mesh files in version 4.0.0. Gmsh provides an open-source alternative with a graphical user interface.

Known issues

The default PETSc options provide a computationally expensive preconditioner when solving incompressible elasticity problems in parallel. We expect to have a more optimal preconditioner in the next release.

Contributors

Brad Aagaard
Matthew Knepley
Charles Williams
Grant Block
Daniel Douglas
Lorraine Hwang
Rezgar Shakeri
Robert Walker

Download v4.0.0

Binary Packages

Linux x86_64 (glibc 2.12 and later)
macOS x86_64 (macOS 10.15 and later; works on x86_64 and arm64 processors)
macOS arm64 (macOS 11.0 and later; only works on arm64 processors)

Source Code

If you need to build PyLith from source, we strongly recommand that you use the PyLith Installer utility to configure and build the PyLith code and its dependencies. If you use the installer you do not need to download the PyLith and PETSc tarballs; the installer will download them automatically.

PyLith

Category