[CIG-ALL] PyLith 1.3.0

[Brad Aagaard]

Greetings,

I am pleased to announce the release of PyLith 1.3.0, a finite-element
code designed to solve dynamic elastic problems and quasi-static
viscoelastic problems in tectonic deformation.

This release adds two new time stepping options (nonuniform
user-specified and automatic constitutive model controlled) and
permits specification of an initial stress state. This release also
includes some minor improvements to the Sieve implementation, fixes
one bug, and corrects typos in the manual and installation
instructions. We encourage all users of previous PyLith releases to
switch to this latest release.

You can download the source code and binaries from

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

Installation instructions are in the bundled README and INSTALL
files, as well as in the User Manual on the web page.


RELEASE NOTES

   * Time stepping options

     In addition to a uniform, user-specified time step, which is the
     default, there are two new time-stepping options. The user may
     supply a file with nonuniform time steps or, for quasi-static
     simulations, the user can request the code to compute the time
     step automatically. For the current bulk constitutive models, the
     automatically determined time step is independent of the
     deformation rate, so it is uniform.

   * Initial stresses

     Users may optionally supply an initial stress state for each
     material via a spatial database. The initial stress state can
     balance the gravitational body forces so that the model is in
     equilibrium without any deformation. This implementation of an
     initial stress state is a prelude to specifying a more complete
     initial state for each material, which will be available in a
     future release.

   * Bug fixes

     - Fixed labeling of physical properties in output for the Maxwell
       viscoelastic and generalized Maxwell viscoelastic materials (mu
       and lambda were switched).

MIGRATING FROM VERSION 1.2 TO 1.3

   The implementation of different options for controlling the time
   step requires adjusting input parameters from those used with PyLith
   1.2. The time stepping is now specified under the time-stepping
   formulation rather than the problem (i.e., one level deeper).