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Minutes 10 July 2006

Present: Shane, Karl, Travis.

An "audio recording": is available.

Audio recording of meetings

  • This is the last meeting that will be recorded unless more interest is shown.

MPI Test problem proposal and implementation

  • cm performs much better with "grid-based fem" than with the original advection-diffusion fem code.
    • The problem solved is not the test problem (initial conditions are not set, boundary conditions are Neumann, and there is an Euler integration of a cubic cell model) but provides an indication of what to expect if the test problem were solved similarly.
      • a 1000x1000 element problem with 50 time steps of 0.001 and a maximum of 4 iterations in each CG solve took 82 seconds using 1.1 GB resident memory (2.6 virtual). The single matrix assembly took 19.4 seconds.
      • A similar libmesh problem but with matrix assembly at each time step took 379 seconds using 1.3 GB resident memory (1.4 virtual).
  • Sundance
    • Doesn't have a high level time-stepping object.
    • Nice high level classes for describing the mathematics of the problem (in a variation form).
    • Easy to get it to work, even for a problem for which it may not have been intended.
    • Results on Using Sundance seem reasonable in comparison to libmesh given that it is doing more iterations in each linear solve.
    • Code that uses Sundance can be written in an easy to read manner.
    • Currently provides only Triangular/tet elements but quads/hexs shouldn't be a problem.
    • Not sure about basis functions in addition to Lagrange.
    • No AMR.
    • A few seg faults happening
      • solver reaches max iterations
      • running with 4 processes
    • Feels a bit like still an academic project; not sure what applications it is being used for.
    • Used for Navier Stokes.
    • High level operators provided by epetera
      • Perhaps this could be imported to other packages.


  • Shane wants to establish a dialog with libmesh developers and suggests asking about assembling only once.
    • Karl says this might be in documentation; we should read this first. If we want to establish a dialog then we should get to the point and explain our position.
  • We want to appear as developers (not like people building a Windows gui).
  • We could ask what would be involved in parallelization of mesh

What about other packages?

  • LifeV and freepooma have not yet been considered.
  • Do we check these out now before spending more time on libmesh?
  • Have we enough evidence that using an existing package is sensible?

Next meeting 11am Thursday 20 July.