[petsc-users] coordinate point location in mesh

[Dharmendar Reddy]

Hello
        Do i am currently cloned petsc using git. Looks like the function
you mentioned is in knepley/pylith. How do i switch to that branch ?
I guess i need to pull the branch before switching ?
git branch knepley/pylith
and
reconfigure ?

May not be of (immediate) concern but an observation about the
LocatePoint_<Simplex> codes.

I see that test is done for every cell by calculating the ref cell mapped
coordinates for a given point. It might help speed up things if there is a
test to first check if the given point is with in the square/cube
containing the simplex.

The above test will make sure that the point is inside the cell or with in
one of the adjoining cells.

I am assuming the DMPlex object has information about cells adjoining a
given cell. Since the LocatePoint_<Simplex> calculates the ref cell mapped
coordinates, I may be wrong here but i am thinking we can use that
information to check outside which facet of the refcell the given point is
and then try to locate the point in the cell sharing that facet.

Thanks
Reddy

On Thu, Apr 4, 2013 at 3:37 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Fri, Apr 5, 2013 at 6:29 AM, Dharmendar Reddy <dharmareddy84 at gmail.com>wrote:
>
>> Hello,
>>          Is there any DMPlex function which will tell me to which DMPlex
>> point a given coordinate point  belongs to ?
>> I am looking for cell id given a coordinates of a point.
>>
>
> I have experimental code to do this, DMPlexLocatePoint(). There are tests,
> but they are not that stringent for
> hexes. Let me know if this works for you.
>
>    Matt
>
>
>> If not,  I can think of writing of a test for point in cell
>> and loop over cells to find the cell id. Any suggestions for doing this ?
>>
>>
>> The physical problem i am looking at is a Poisson equation in a given
>> domain.
>>
>> - \Delta u(x) = rho(x)  where rho is a sum of delta functions randomly
>> located in the domain.
>> --
>> -----------------------------------------------------
>> Dharmendar Reddy Palle
>> Graduate Student
>> Microelectronics Research center,
>> University of Texas at Austin,
>> 10100 Burnet Road, Bldg. 160
>> MER 2.608F, TX 78758-4445
>> e-mail: dharmareddy84 at gmail.com
>> Phone: +1-512-350-9082
>> United States of America.
>> Homepage: https://webspace.utexas.edu/~dpr342
>>
>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>



-- 
-----------------------------------------------------
Dharmendar Reddy Palle
Graduate Student
Microelectronics Research center,
University of Texas at Austin,
10100 Burnet Road, Bldg. 160
MER 2.608F, TX 78758-4445
e-mail: dharmareddy84 at gmail.com
Phone: +1-512-350-9082
United States of America.
Homepage: https://webspace.utexas.edu/~dpr342
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