== 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%] [[br]]
     DMPlex implementation is better integrated within PETSc. Smaller memory usage. Developed to support multiphysics and higher order discretizations.

  * Higher order basis functions expert [0%] [[br]]
     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%] [[br]]
     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 [[br]]
        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 [[br]]
     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 =====