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PyLith Development Plans, May 2017

Priorities for PyLith software development, such as new features and enhancements. This a draft for community comment (May 19, 2017).

This plan attempts to balance meeting short-term objectives of delivering high priority, new features and meeting long-term objectives of extending the code to solve a broader range of scientific problems.

Version 3.0 (2017)

  1. Multiphysics [30%]
    • Implement modular approach for specifying governing equations and computing residuals and Jacobians.
    • Incompressible elasticity via a pressure field [20%]
  2. Higher order basis functions [50%]
    • Allow user to select order of basis functions independent of the mesh (which defines the geometry). This permits higher resolution for a given mesh.
  3. Switch to using PETSc time-stepping (TS) algorithms. [75%]
    • 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.
  4. Update user manual
    • Convert from LyX to LaTeX for ease of maintenance and editing. [100%]
    • Reorganize for multiphysics implementation. [10%]
    • Reorganize examples. [5%]
      • Focus on demonstrating the range of physics and features beginning with simple cases and building towards more complex cases.
      • Include ParaView Python scripts for plotting results.
      • Consider moving examples to Jupyter notebooks; export to PDF files for “print” documentation.

Version 3.1 (early 2018)

  1. Improve fault formulation for spontaneous rupture [10%]
    • Removes inner solve associated with updating Lagrange multipliers. This will significantly accelerate the nonlinear solve.
  2. Allow full specification of the initial conditions (solution and state variables) [0%]
  3. Add additional multiphysics implementations and rheologies
    • Poroelasticity [5%]
  4. Convert to Python 3 and Pyre 1.0.

Version 3.X (TBD)

  1. Add additional multiphysics implementations and rheologies
    • Drucker-Prager bulk rheology with relaxation to yield surface
    • Elasticity + heat flow
  2. Reorganize output for time-dependent Green's functions and adjoints
  3. Multilevel nonlinear solve
  4. Radial basis functions for spatial databases
  5. Use threading to accelerate integrations on multi-core machines.

Version 4.0 (TBD)

  1. Earthquake cycle modeling
    • Same mesh for dynamic and quasi-static parts (dynamic → quasi-static, quasi-static → dynamic, complete cycle)
  2. Create strain hardening/softening 2-D and 3-D Drucker-Prager elastoplastic models.
  3. Moment tensor point sources via equivalent body forces [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.

Features for Future Releases

  • Major features
    1. Earthquake Cycle Modeling
      • Different meshes for dynamic and quasi-static parts
        • 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.
    2. Data assimilation
      • Use flexibility of multiphysics implementation to support inclusion of data assimilation
  • Minor features
    1. Begin implementation of data assimilation capabilities via adjoint equation.
    2. 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.
software/pylith/plans/2017-05.txt · Last modified: 2017/05/19 20:08 by baagaard