==PyLith Development Plans ==
 Software development plans for PyLith
Version 1.8.1 (by mid-late April)
BUG FIXES
Improve solver for rate-state friction and explicit time stepping. difficult [50%]
Remove duplicate impulses in parallel Green's function simulations. done
Version 2.0 (by June workshop)
COMPUTATIONAL SCIENCE
Replace Sieve implementation of finite-element data structures with more efficient DMPlex implementation. expert [80%]
DMPlex implementation is better integrated within PETSc. Smaller memory usage. Developed to support multiphysics and higher order discretizations.

Higher order basis functions expert [0%]
Allow user to select order of basis functions independent of the mesh (which defines the geometry). This permits higher resolution for a given mesh.

Version 2.1 (Fall or Winter 2013)
MAJOR FEATURES
Earthquake cycle modeling difficult
Same mesh for dynamic and quasi-static parts (dynamic -> quasi-static, quasi-static -> dynamic, complete cycle)

MINOR FEATURES
Create strain hardening/softening 2-D and 3-D Drucker-Prager elastoplastic models. intermediate
Attenuation via generalized Maxwell model (bulk and shear relaxation) intermediate [50%]
Moment tensor point sources via equivalent body forces difficult [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.

Candidate Features for Version 2.2 (Spring 2014)
MAJOR FEATURES
Multiphysics
Incompressible elasticity via a pressure field expert
Elasticity + heat flow expert
Elasticity + fluid flow expert
MINOR FEATURES
Time-step based on strain rate intermediate
Accelerate FE integrations using GPUs expert [5%]
Will provide significant speedup to simulations run by many users because most are running on desktop machines that have GPUs.

Features for Future Releases
MAJOR FEATURES
Earthquake Cycle Modeling
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.

MINOR FEATURES
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