[CIG-SHORT] Three questions about pylith

[Ikuo Cho]

Dear PyLith Developers

I recently began to use Pylith and have three questions.

1)About the error measure used in benchmark tests
What factors or rates does Pylith overestimate or underestimate the true
values? (Also, how much do the displacement vectors calculated by Pylith
orient to wrong directions?) Can you tell me any information of
published papers or reports on this problem (if you have)?

 I found that the User Manual has a section on Benchmark tests, where an
error measure is defined by 

error_local = sqrt{integrate ((u^t_i-u^fem_i)**2 dv}/Volume. 

In this case, however, the errors take small values at points distant
from a fault plane even when respective displacement vectors of rigorous
theory and those calculated by Pylith orient to the directions
completely different from each other. 

2) To do a benchmark test
 I tried to do numerical calculations by Pylith to answer to the above
question by myself.  I downloaded parameter files required for an
example of strike slip via a web site 
http://www.geodynamics.org/svn/cig/short/3D/PyLith/benchmarks/trunk/quasistatic/strikeslipnog. 
However, this trial failed by a fetal error. So, I hope you can tell me
what was wrong. (I suspect the difference in the version of Pylith: I
used Pylith of ver. 1.1.2).

 I created a mesh file "strikeslip_hex8_1000m.exo" from files of createbc.jou,
geometry.jou, and mesh_hex8_1000m.jou. Next, I typed "pylith
strikeslip_cubit.cfg strikeslip_hex8_1000m.cfg" (The cfgfile timedep.cfg
was not included in this case for simplicity). Of course, I placed the
following files in the same directory:

fixeddisp_analytic_xneg.spatialdb
fixeddisp_analytic_xpos.spatialdb
fixeddisp_analytic_ypos.spatialdb
fixeddisp_analytic_zneg.spatialdb
fixeddisp_zero.spatialdb
mat_elastic.spatialdb
mat_maxwell.spatialdb
slip_tapered.spatialdb
slip_uniform.spatialdb
sliptime_uniform.spatialdb

Finally, I had the following error.

RuntimeError: Error occurred while reading spatial database file ''.
Could not open spatial database file '' for reading.

I have attached a logfile to this email.

３）Animations created by paraview
 Paraview does not always read output files from Pylith in order of time.
Consequently, the resulting animation file does not reproduce
appropriate temporal changes of the numerical solution. Do you have any
idea to deal with this problem?

For example,  the output files from Pylith, 

dislocation_t0000000.vtk
dislocation_t6311520000000.vtk
dislocation_t12623040000000.vtk
dislocation_t18934560000000.vtk
dislocation_t25246080000000.vtk
dislocation_t31557600000000.vtk
dislocation_t63115200000000.vtk
dislocation_t94672800000000.vtk
dislocation_t126230400000000.vtk
dislocation_t157788000000000.vtk
dislocation_t189345600000000.vtk
dislocation_t220903200000000.vtk
dislocation_t252460800000000.vtk
dislocation_t284018400000000.vtk
dislocation_t315576000000000.vtk,

are read by Paraview in the order of 

dislocation_t6311520000000.vtk
dislocation_t189345600000000.vtk
dislocation_t31557600000000.vtk
dislocation_t252460800000000.vtk
dislocation_t94672800000000.vtk
dislocation_t315576000000000.vtk
dislocation_t157788000000000.vtk
dislocation_t0000000.vtk
dislocation_t12623040000000.vtk
dislocation_t220903200000000.vtk
dislocation_t25246080000000.vtk
dislocation_t63115200000000.vtk
dislocation_t284018400000000.vtk
dislocation_t126230400000000.vtk
dislocation_t18934560000000.vtk

Ikuo Cho
----------------------------------------------------------
Ikuo Cho  ( ikuo-chou at aist.go.jp )
Geological Survey of Japan,
National Institute of Advanced Industrial Science and Technology
Tsukuba Central 7, Tsukuba 305-8567 Japan
Tel +81-29-861-3891, Fax +81-29-861-3682
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