[CIG-SHORT] Grid processing error

[Brad Aagaard]

Birendra,

The error you encountered is related to setting a Neumann (traction) 
boundary condition on a surface with a normal parallel to the z-axis. 
The default parameters allow PyLith to uniquely calculate the two shear 
directions and normal direction at each location provided the normal is 
not parallel to the z-axis. If the normal is parallel to the z-axis, 
then the up_dir parameter for the BC needs to be set to something other 
than the default (0, 0, 1). See examples/3d/hex8/step18 for an example 
and section 6.2.2.1 of the PyLith manual.

Regards,
Brad


On 03/20/2012 01:03 AM, Birendra jha wrote:
> Dear developers,
>
> When trying to run the attached problem of axial compression
> (extended version of twocells/twohex8/axialdisp.cfg), I get following
> error during pre-processing:
>
> mpinemesis:
> ../../../pylith-1.6.3/libsrc/pylith/feassemble/CellGeometry.cc:252:
> static void
> pylith::feassemble::CellGeometry::_orient2D(pylith::double_array*,
> const pylith::double_array&, double, const pylith::double_array&):
> Assertion `mag>  0.0' failed.
>
> I don't know why the CellGeometry is identified as 2D quadrilateral
> when it is all hex cells. Probably the issue lies in a Submesh that
> got created with 4 nodes at z=0 and z=L?
>
> Any help will be highly appreciated.
>
> Thanks and regards Birendra