[CIG-ALL] PyLith 1.1.0

[Brad Aagaard]

Greetings,

I am pleased to announce the release of PyLith 1.1.0, a finite element
code designed to solve quasi-static viscoelastic problems in tectonic
deformation.

This release adds a number of new features, including Neumann
(traction) boundary conditions, absorbing boundary conditions,
Dirichlet boundary conditions with displacement and/or velocity
values, a generalized Maxwell viscoelastic bulk constitutive model,
and output of fault and material information (state variables and
diagnostic information). We have also added a number of consistency
checks to trap and report errors in the input parameters. The manual
has been updated to reflect the new features and also includes
detailed installation instructions for building from source. We
encourage all users of PyLith 1.0 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:

  * New boundary conditions

    - Neumann (traction) boundary conditions

    - Absorbing boundary conditions via simple, tuned dampers

    - Dirichlet boundary conditions with displacement and/or velocity values

  * New bulk constitutive models

    - Generalized Maxwell viscoelastic model 

  * New output implementation

    The output to VTK files has been completely rewritten. This new
    implementation includes output of physical properties and state
    variables associated with the bulk constitutive models, as well as
    output of fault information (earthquake rupture parameters and
    slip and traction time histories). Additionally, the VTK file with
    the solution no longer includes fault related values- it contains
    just the displacement field over the domain as one would expect. A
    user can now also request output of the solution over an arbitrary
    number of sub-domains of the domain boundary, e.g., the ground
    surface. For each of these different kinds of output, the
    frequency of output and the values included can be customized by
    the user. The names of the VTK files and the variable names have
    also been adjusted to permit animation of solutions within most
    VTK visualization tools.

  * New spatial database implementations

    Spatialdata includes two new spatial database implementations. The
    SCECCVMHDB provides a seamless interface to the SCEC CVM-H seismic
    velocity model for elastic material properties. The UniformDB
    permits creating a spatial database for uniform values using only
    .cfg files or the command line; this eliminates the need to create
    a SimpleDB database file with one location.

  * Dynamic arrays of components in Pyre

    Pyre now contains dynamic arrays of components, eliminating the
    need for containers for materials, boundary conditions, and
    faults.

  * Better consistency checking of input parameters

    - Uniqueness of material identifiers for materials and faults is
      enforced.

    - The material identifier of each cell in the mesh is checked to
      make sure it matches a material model.

    - Each boundary, interface condition, and output group is checked
      to make sure it exists in the mesh.

  * Bug fixes

    - Fixed bug causing segmentation fault with multiple,
      non-overlapping Dirichlet boundary conditions applied to vertices.

    - Fixed numerous bugs related to explicit time integration for
      dynamic problems.

    - Eliminated several small memory errors.

    - Fixed several bugs associated with writing VTK files in parallel.

  * Known issues

      - PyLith still uses much more memory that PyLith 0.8 due to the
        current general Sieve implementation. A much more efficient,
        albeit less general Sieve implementation is under
        development. Additionally, distribution of the mesh will also be
        improved in a future release.

      - The preconditioner for explicit time stepping provides
        relatively poor overall performance compared to a direct solve
        with traditional mass lumping. An appropriate preconditioner and
        traditional mass lumping will be supported in a future release.

MIGRATING FROM VERSION 1.0 TO 1.1

  There are two new features in PyLith version 1.1 that require users
  to adjust input parameters from those used with PyLith 1.0. The
  elimination of containers in favor of the dynamic arrays of
  components present in the latest version of Pyre requires switching
  from setting the container to specifying the array of components on
  the command line or .cfg file. Additionally, the new implementation
  of output requires a completely new set of parameters. When using
  PyLith version 1.1 with a problem previously setup for PyLith 1.0,
  look for warnings about unknown components and settings in the
  output at the beginning of a run.