[CIG-SHORT] PyLith v1.9.0 released

[Brad Aagaard]

Greetings,

I am pleased to announce the release of PyLith 1.9.0, a finite-element
code designed to solve dynamic elastic problems and quasi-static
viscoelastic problems in tectonic deformation.

This release fixes several bugs in PyLith v1.8.0. We strongly recommend
all users of previous PyLith releases switch to this latest
release.

No changes are needed in .cfg files to switch from v1.8.0 to
v1.9.0. Version 1.9.0 does includes some changes to the friction and
material model interfaces, so extensions do require changes. See the
templates for details.

You can download the source code and binaries from

     http://geodynamics.org/cig/software/packages/short/pylith

Detailed installation instructions for the binary packages are in the
User Manual with detailed building instructions for a few platforms in
the INSTALL file bundled with the PyLith Installer utility.


RELEASE NOTES - PyLith v1.9.0

* New features

   * Added Newton-Raphson algorithm for spontaneous rupture simulations
     with explicit-stepping.

     Enforcing the friction criterion in a spontaneous rupture
     simulation with explicit time-stepping now uses a Newton-Raphson
     algorithm to find the correct traction increment. This provides a
     more stable numerical solution and eliminates oscillatory behavior
     when using rate-state friction.

     Added SCEC spontaneous rupture benchmark TPV102 to the benchmark
     repository. PyLith produces results that closely match several other
     finite-element codes.

* Bug fixes

   - Fixed two MPI related bugs in computing Green's functions in
     parallel. The number of impulses corresponded to only those on
     process 0 and the output of the impulses for vertices on processor
     boundaries was inconsistent.

   - Corrected computation of fault tractions (Lagrange multipliers) on
     process boundaries for prescribed slip with explicit time stepping.

   - Fixed bug when reading in list of output points with just one
     point.

   - Adjusted autoconf Python setup macro to remove temporary
     sysconfig.pyc file.

   - Added check to make sure degree of freedom specified in Dirichlet
     BC is consistent with spatial dimension of problem.

   - Corrected two typos in the manual related to fault opening and
     tractions in examples/3d/hex8/step20 and updating to the use of
     cell.dimension for the quadrature scheme with tetrahedral cells.