[CIG-SHORT] benchmarking results so far

[Brad Aagaard]

Hi all:

The benchmarking results so far are given below.

NOTE: PyLith and GeoFEST output displacements for nodes on the fault 
as the average of the two sides of the fault, so these values don't 
agree very well with the analytic solution. This is very evident in 
plots of the local error. Femlab outputs the displacements as one 
expects (offset across the fault) so its error is much less.

Attached image shows the local (element) error (difference) for PyLith 
relative to GeoFEST at t=10 yrs (only elements with errors > 0.001 
are shown).

Error: L2 norm integrated over the volume and normalized by the 
volume, which can be considered to be the average difference in 
displacement over the volume. I also calculate the L2 normal 
integrated over each element normalized by the element volume, which 
can be considered the average difference in displacement over the 
element.

I'll try to get some more plots put together by early next week. The 
differences between PyLith and GeoFEST are small but there is 
definitely a little difference between the two in the viscoelastic 
solution.

Brad

======================================================================
REVERSE SLIP, NO GRAVITY
======================================================================

1000m UNIFORM RESOLUTION

Time Step: 0
  PyLith-0.8, error wrt analytic:   4.5162e-02
  GeoFEST, error wrt analytic:   4.5165e-02
  Femlab, error wrt analytic:   2.7168e-03

Time Step: 0
  PyLith-GeoFEST, difference:   2.8474e-04
Time Step: 10
  PyLith-GeoFEST, difference:   9.6947e-04
Time Step: 50
  PyLith-GeoFEST, difference:   8.0500e-04
Time Step: 100
  PyLith-GeoFEST, difference:   5.6430e-04


500m UNIFORM RESOLUTION

Time Step: 0
  PyLith-0.8, error wrt analytic:   3.2159e-02
  GeoFEST, error wrt analytic:   3.2163e-02
Time Step: 0
  PyLith-GeoFEST, difference:   3.0927e-04
Time Step: 10
  PyLith-GeoFEST, difference:   9.7460e-04
Time Step: 50
  PyLith-GeoFEST, difference:   8.3009e-04
Time Step: 100
  PyLith-GeoFEST, difference:   5.8660e-04
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