== !PyLith Development Plans, Nov 2016 == Priorities for !PyLith software development, such as new features and enhancements. This a draft for community comment (Nov 7, 2016). 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 (Spring 2017) === # Multiphysics [[Image(expert.png, 40px)]] 30% * Implement modular approach for specifying governing equations and computing residuals and Jacobians. [[Image(expert.png, 40px)]] * Incompressible elasticity via a pressure field [[Image(intermediate.png, 25px)]] 20% * Poroelasticity [[Image(difficult.png, 25px)]] 5% # Higher order basis functions {[[Image(difficult.png, 25px)]] 25% * 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. [[Image(intermediate.png, 25px)]] 25% * 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. # Improve fault formulation for spontaneous rupture [[Image(intermediate.png, 25px)]] 10% * Removes inner solve associated with updating Lagrange multipliers. This will significantly accelerate the nonlinear solve. # Allow full specification of the initial conditions (solution and state variables) [[Image(intermediate.png, 25px)]] 0% # Update user manual * Convert from !LyX to !LaTeX for ease of maintenance and editing. [[Image(easy.png, 25px)]] 0% * Reorganize for multiphysics implementation. [[Image(intermediate.png, 25px)]] 5% * Reorganize examples. [[Image(intermediate.png, 25px)]] 0% * 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 (late 2017) === # GUI interface for specifying simulation parameters [[Image(difficult.png, 25px)]] # Add additional multiphysics implementations and rheologies * Drucker-Prager bulk rheology with relaxation to yield surface [[Image(intermediate.png, 25px)]] * Elasticity + heat flow [[Image(difficult.png, 25px)]] # Reorganize output for time-dependent Green's functions and adjoints [[Image(intermediate.png, 25px)]] # Multilevel nonlinear solve [[Image(expert.png, 40px)]] # Radial basis functions for spatial databases [[Image(intermediate.png, 25px)]] # Convert to Python 3 and Pyre 1.0. === Version 4.0 (TBD) === # Earthquake cycle modeling {[[Image(difficult.png, 25px)]] * Same mesh for dynamic and quasi-static parts (dynamic -> quasi-static, quasi-static -> dynamic, complete cycle) # Create strain hardening/softening 2-D and 3-D Drucker-Prager elastoplastic models. [[Image(intermediate.png, 25px)]] # Moment tensor point sources via equivalent body forces [[Image(difficult.png, 25px)]] 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 ==== # Earthquake Cycle Modeling * Different meshes for dynamic and quasi-static parts [[Image(expert.png, 40px)]] * 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. # Data assimilation * Use flexibility of multiphysics implementation to support inclusion of data assimilation [[Image(expert.png, 40px)]] ==== Minor features ==== # Begin implementation of data assimilation capabilities via adjoint equation. # Combined prescribed slip / spontaneous rupture fault condition [[Image(difficult.png, 25px)]] * 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. [[Image(difficult.png, 25px)]] ---- ==== difficulty rating system ==== ||[[Image(easy.png, 25px)]] easy ||[[Image(intermediate.png, 25px)]] intermediate ||[[Image(difficult.png, 25px)]] difficult ||[[Image(expert.png, 40px)]] expert || ''based on the ski trail rating system''