[CIG-SHORT] Stress issue with spherical model

[Brad Aagaard]

On 11/28/2016 07:31 PM, Demian Gomez wrote:
> Brad,
>
> How do I "verify what initial stresses PyLith is using by turning off
> gravity and not having any deformation"? I can turn off gravity and let
> the displacement at the fault be = 0, but how do I constrain the
> displacements everywhere in the model so that after I run Pylith the
> stresses are = to the initial stresses?

If you specify initial stresses with zero displacement BC and no fault 
slip, then there should not be any deformation and the computed stresses 
will be equal to the initial stresses.

> Also, the idea of querying the spatialdb with a Python script is good,
> but unfortunately, the example you refer to (exodus_add_properties.py)
> it's too simple for my case. After several hours of trial and error I
> wasn't able to query the spatialgriddb using the coordinates of my mesh.
> I think the problem is related to the coordinate system. From the
> example, I've defined my coordinate system object as:
>
>     # Coordinate system for mesh (must match coordsys in ExodusII file)
>     cs = CSGeo()
>     cs.inventory.ellipsoid = "sphere"
>     cs.inventory.datum_vert = "ellipsoid"
>     cs.inventory.is_geocentric = True
>     cs._configure()
>     cs.initialize()
>
> When I try to query the geocentric coordinates of the model, I do not
> get any values from the db (vector err full of ones). If I use points in
> lat lon h, then the query returns values (err vector full of zeros).
> I've attached the python script based on the example you suggested.

There is a difference in names between the .cfg parameters and the Pyre 
variables. For variables we don't use underscores and use camelCase 
(datum_vert -> datumVert).

cs.inventory.ellipsoid = "sphere"
cs.inventory.datumVert = "ellipsoid"
cs.inventory.isGeocentric = True

Regards,
Brad