[CIG-SHORT] stress in vtk files

[Ethan Coon]

If you're handy in python, you may find the pyvtk module
( http://cens.ioc.ee/projects/pyvtk/ ) handy for loading the data and
saving the results without having to write the i/o yourself. 

As far as I know, neither paraview nor MayaVi makes it easy to do this,
but at least with MayaVi you can script the image generation in python. 

Ethan

On Sat, 2008-05-17 at 16:21 -0400, Tabrez Ali wrote:
> Yes I wanted to loop over multiple vtk files (containing displacement 
> data) and then subtract data in consecutive files to get the velocities. 
> Something like:
> 
> do i=1,500
> (velocity_data_i.vtk) = (data in disp_i+1.vtk) - (data in disp_i.vtk)
> end do
> 
> I think its easier for me to write a shell script for now.
> 
> Thanks anyway
> Tabrez
> 
> 
> Brad Aagaard wrote:
> > I was assuming that Tabrez wants to create velocity time histories. 
> > Thorsten is right that the calculator makes it very easy to do some 
> > simple post-processing. It does not appear to be able to do looping 
> > over time steps for processing of a series of snapshots. I could be 
> > wrong and if someone knows how to create velocity time histories from 
> > displacement snapshots, it would be great to learn how to do it.
> >
> > Brad
> >
> > Thorsten Becker wrote:
> >> On Sat, 2008-05-17 at 11:39 -0700, Brad Aagaard wrote:
> >>> Tabrez Ali wrote:
> >>>> PyLith Users/Developers
> >>>>
> >>>> The vtk files containing stress results have six values for each 
> >>>> component but which is what?
> >>> Good question. I think this is missing from the manual.
> >>> The order for the stress and strain components is
> >>>
> >>> 1-D: sigma_xx
> >>>
> >>> 2-D: sigma_xx, sigma_yy, sigma_xy
> >>>
> >>> 3-D: sigma_xx, sigma_yy, sigma_zz, sigma_xy, sigma_yz, sigma_xz
> >>>
> >>> Brad
> >>>
> >>>
> >>>> Also is there a supereasy way "within" Paraview to obtain annual 
> >>>> velocities from displacement data available each year, say from 
> >>>> 0-500 yrs.
> >>
> >> I'm not sure if I understand the question, but Paraview has a calculator
> >> tool (Filter->Alphabetical->Calculator, in 3.2.1, for example) that can
> >> operate on all model scalars (including coordinates) and vectors (such
> >> as velocities).
> >>
> >>
> >>> I don't think there is an easy way. ParaView has a scripting 
> >>> interface but I have no experience using it. This is one reason why 
> >>> we want to add HDF5 output. It is very easy to write simple Matlab 
> >>> or Python scripts to process data in HDF5 files.
> >>>
> >>> Brad
> >>>
> >>> _______________________________________________
> >>> CIG-SHORT mailing list
> >>> CIG-SHORT at geodynamics.org
> >>> http://geodynamics.org/cgi-bin/mailman/listinfo/cig-short
> _______________________________________________
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-- 
-------------------------------------------
Ethan Coon
DOE CSGF - Graduate Student
Dept. Applied Physics & Applied Mathematics
Columbia University
212-854-0415

http://www.ldeo.columbia.edu/~ecoon/
-------------------------------------------