PyLith Development Plans

Software development plans for PyLith

Version 1.7 (by June workshop)

GENERAL

• Output of solution at arbitrary points via interpolation of solution. done
• Add 2-D plane strain version of the Drucker-Prager elastoplastic rheology. done
• Add 2-D plane strain version of the power-law viscoelastic rheology. done
• Elastic pre-step option for time-dependent problems. Remove assumed elastic pre-step at time step 0. done
• Add —initialize_only property to Problem easy (0%)
  Permit users to stop simulation before time stepping in order to diagnose parameter settings.

QUASI-STATIC

• Static Green’s functions for fault slip. done

DYNAMIC

• None

COMPUTATIONAL SCIENCE

• Switch to new Sieve implementation. expert (0%)
  C implementation better integrated with !PETSc. Smaller memory usage. Facilitates multiphysics and higher order discretizations.

Version 1.8 (Fall or Winter 2012)

GENERAL

• Refactor initial fault tractions easy (5%)
  Create Nucleation object with spatial and temporal perturbation of tractions from initial value.

QUASI-STATIC

• Create strain hardening/softening 2-D and 3-D Drucker-Prager elastoplastic models.

DYNAMIC

• Compute stable time step for explicit time integration easy (5%)
• Attenuation via generalized Maxwell model (bulk and shear relaxation) intermediate (50%)

COMPUTATIONAL SCIENCE

• Accelerate FE integrations using !GPUs difficult (25%)
  Will provide significant speedup to simulations run by many users because most are running on desktop machines that have GPUs.

Candidate Features for Version 2.0 (Spring 2013)

MAJOR FEATURES

• Multiphysics
  1. Incompressible elasticity via a pressure field expert
  2. Elasticity + heat flow expert
  3. Elasticity + fluid flow expert
• Earthquake cycle modeling
  1. Same mesh for dynamic and quasi-static parts difficult
     1. Dynamic -> quasi-static
     2. Quasi-static -> dynamic
     3. Complete cycle
  2. Different meshes for dynamic and quasi-static parts expert
     Requires interpolation of fields between different meshes/discretizations and may require extrapolation of solutions when quasi-static problems span a larger domain than the dynamic problems.
• Use interpolated meshes (cells, faces, edges, vertices) to permit higher order basis functions expert

MINOR FEATURES

• Moment tensor point sources difficult
  Moment tensor point sources provide a mesh independent deformation source that is better suited for Green’s function calculations than slip on a fault surface via cohesive cells.

• Time-step based on strain rate intermediate
• Pressure field for incompressible elasticity problems expert
• Use KD tree search algorithm to allow output of time histories at an arbitrary location difficult
• Combined prescribed slip / spontaneous rupture fault condition difficult
  Use fault constitutive model to control slip on fault except during episodes of prescribed slip. Need some way to describe when to turn on/off prescribed slip.

• Use threading to accelerate integrations on multi-core machines. difficult

Created on 06 Jan 2021, Last modified on 06 Jan 2021