DevelopmentPlan 2019 06

PyLith Development Plan, June 2019

Add ability to output residual field during nonlinear solve for debugging
Release bugfixes
- Fix material deallocation memory issue.
- Fix PETSc version test for tagged release.

Multiphysics
- Implement modular approach for specifying governing equations and computing residuals and Jacobians. [100%]
- Incompressible elasticity via a pressure field [95%]
Higher order basis functions [100%]

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 for quasi-static simulations. [100%]

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.
Modular approach for initial conditions [100%]
Testing via Method of Manufactured Solutions [80%]

Use PETSc time-stepping (TS) algorithms for dynamic simulations. [50%]
Improve fault formulation for spontaneous rupture [10%]

Removes inner solve associated with updating Lagrange multipliers. This will significantly accelerate the nonlinear solve.
Convert to Python 3
Reorganize output for time-dependent Green's functions and adjoints
Poroelasticity [15%]

Contribution led by Josimar da Silva and Robert Walker.
Parallel mesh loading

Requires creating cohesive cells in parallel.
Integration with libCEED for fast high order residual evaluation in dynamic simulations

Contribution led by Jed Brown.

Earthquake cycle modeling

(dynamic → quasi-static, quasi-static → dynamic, complete cycle)
Reimplementation of small strain formulation
Moment tensor point sources [5%]

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.

Drucker-Prager bulk rheology with relaxation to yield surface
Create strain hardening/softening 2-D and 3-D Drucker-Prager elastoplastic models.
Elasticity + heat flow
Multilevel nonlinear solve
Radial basis functions for spatial databases
Adaptive mesh refinement
Adjoint for data assimilation
Combined prescribed slip / spontaneous rupture fault condition

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.