Project Homepage: http://www.llnl.gov/CASC/PVODE

Objective:
 
  (a) Build a systematized trio of sequential and parallel solvers
   for ordinary differential equations, nonlinear algebraic systems,
   and differential-algebraic equation systems, based on existing
   successful Fortran packages.

   (b) Minimize duplication of code and maximize usage flexibility.

Approach:

  (a) We developed a modular software design, starting with CVODE and
   its parallel extension PVODE for ODE systems, but also applicable to
   the nonlinear system solver KINSOL and the DAE solver IDA.  We use
   the SPMD programming model with message-passing.
   (b) The three solvers share a single set of vector kernels, for which
   there is a sequential and a parallel version.  All machine-dependent
   coding is isolated to this module.
   (c) The three solvers also share a single set of linear system solvers
   -- two with direct methods and one with a Krylov iterative method,
   scaled preconditioned GMRES.  (Only the GMRES solver is parallel.)
   The user selects a linear solver independently of the calls to the
   main solver.

Recent FY98 accomplishments:  PVODE and KINSOL were completed and released, and usage documentation
   was written.  Work on IDA was started.

Plans for FY99: The basic IDA solver is written.  Tasks remaining for IDA include the
   interface to the band solver, routines to calculate consistent initial
   conditions, preconditioners based on band-block-diagonal approximations,
   and testing.

Tool availability: PVODE and KINSOL are available generally, on request.
   IDA is being released within LLNL/CASC.

Participants and affiliations: Alan Hindmarsh and Allan Taylor, LLNL/CASC