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 very similar to 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.

