# Re: [petsc-users] PETScFE Point Source

```On Fri, Apr 13, 2018 at 2:07 PM, Stefano Zampini <stefano.zamp...@gmail.com>
wrote:```
```
> What do you mean by point sources? Dirac's delta terms ? If so, these
> translates into basis function evaluations , and should not be hard to
> support it, but it will require a different API. Matt?
>

That is another thing you could do. We will do that shortly.

Matt

> Il Ven 13 Apr 2018, 20:51 Robert Walker <rlwal...@usc.edu> ha scritto:
>
>> Ok, let me rephrase that...something like way FEniCS (if i remember
>> correctly) handles this ... between two values with a very small difference
>> between them on each axis? Is there an example of something like that to
>> use as a security blanket from which to expand?
>>
>> Robert
>>
>> Robert L. Walker
>> MS Petroleum Engineering
>> Mork Family Department of Chemicals and Materials Sciences
>> University of Southern California
>> ----------------------------------------------
>> Mobile US: +1 (213) - 290 -7101
>> Mobile EU: +34 62 274 66 40
>> rlwal...@usc.edu
>>
>> On Fri, Apr 13, 2018 at 10:46 AM, Matthew Knepley <knep...@gmail.com>
>> wrote:
>>
>>> On Fri, Apr 13, 2018 at 1:40 PM, Robert Walker <rlwal...@usc.edu> wrote:
>>>
>>>> Hello,
>>>>
>>>> Is there an example of application of a point source in one of the
>>>> tutorial  PETScFE style examples? Ideally this would be some point on the
>>>> interior, and not necessarily on a boundary.
>>>>
>>>> Thanks, and apologies in advance if this is a stupid question,
>>>>
>>>
>>> No, good question. You would have to decide what that meant in FEM
>>> terms. All the internal integrals are done
>>> with quadrature. So putting the source at a quadrature point would work,
>>> although its a little difficult to know where
>>> they will be. You could smooth it out a little, and check coordinates in
>>> the forcing function. Last, you could check
>>> for a "close enough" quadrature point and put it there. I think making a
>>> slightly extended source is usually best.
>>>
>>>   Thanks,
>>>
>>>      Matt
>>>
>>>
>>>> Robert
>>>>
>>>>
>>>> Robert L. Walker
>>>> MS Petroleum Engineering
>>>> Mork Family Department of Chemicals and Materials Sciences
>>>> University of Southern California
>>>> ----------------------------------------------
>>>> Mobile US: +1 (213) - 290 -7101
>>>> Mobile EU: +34 62 274 66 40
>>>> rlwal...@usc.edu
>>>>
>>>
>>>
>>>
>>> --
>>> What most experimenters take for granted before they begin their
>>> experiments is infinitely more interesting than any results to which their
>>> -- Norbert Wiener
>>>
>>> https://www.cse.buffalo.edu/~knepley/
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.caam.rice.edu_-7Emk51_&d=DwMFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=BWOpUsAp5dvI5cUiP4uZxQ&m=NhwycEffStNWdPC1pT8qnGZOOnaReNM_T0V8yU1UKHE&s=qwCDj6rCWjIJ1T-NmL3j1bZCdrFx5cOVzTA-l0e0W0o&e=>
>>>
>>
>>

--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their