[petsc-users] PetscFECreateDefault in Fortran

Matthew Knepley knepley at gmail.com
Fri Jun 2 08:52:50 CDT 2017 

On Thu, Jun 1, 2017 at 6:29 PM, Justin Pogacnik <j.pogacnik at auckland.ac.nz>
wrote:

> Hi Matt,
>
> ​Yes, I was using the QuadratureGetData in the past and the results were
> good. I wasn't sure why that would have changed recently. Looking at the
> example (in test directory, not tutorial), it looks like the two
> interesting pointers are pEC and pES. pEC's target is EC, which is
> explicitly set. Does pES have no target? In my code, I set (basically the
> same for q_points as well):
>
> PetscReal, target, dimension(8) :: q_weights
>
> PetscReal, pointer :: pq_weights(:)
>
>
> then:
>
> pq_weights => q_weights
>
>
> Then call: PetscQuadratureGetData()
>
> When I try to write the quadrature points and weights to see their output,
> I get values like NaN, 3.0e-310, etc.
>
>
> I tried removing the q_weights target (like pES example in the test) and
> that returns a segfault. I've attached my example if that helps. You can
> uncomment the QuadratureView() and see that the points and weights are
> correct.​
>
Okay, when we did the conversion of the F90 interface, the DT module was
left out. I put it back in and your example
started working again. You will need to use 'next' or my fix branch right
now. If you rebuild, the module will be rebuilt
and it should work.

  Thanks,

     Matt

> Thanks again,
>
>
> Justin
> ------------------------------
> *From:* Matthew Knepley <knepley at gmail.com>
> *Sent:* Friday, June 2, 2017 9:57 AM
> *To:* Justin Pogacnik
> *Cc:* petsc-users at mcs.anl.gov
> *Subject:* Re: [petsc-users] PetscFECreateDefault in Fortran
>
> On Thu, Jun 1, 2017 at 2:59 PM, Justin Pogacnik <j.pogacnik at auckland.ac.nz
> > wrote:
>
>> ​All good. Thanks Matt. Will keep an eye out for that update. :)
>>
> I have checked, and I was wrong before. I did write the code for
> PetscQuadratureGet/RestoreData()
> in Fortran. Since it uses array arguments, I used F90. Thus you have to
> use F90 pointers, in the
> same style as DMPlexGet/RestoreCone() in this example:
>
>     https://bitbucket.org/petsc/petsc/src/a19fbe4d52f99f875359274419a2d4
> 0a87edfba3/src/dm/impls/plex/examples/tutorials/ex1f90.F90?
> at=master&fileviewer=file-view-default
>
> Let me know if that is not understandable
>
>   Thanks,
>
>     Matt
>
>> -Justin
>> ------------------------------
>> *From:* Matthew Knepley <knepley at gmail.com>
>> *Sent:* Friday, June 2, 2017 12:52 AM
>>
>> *To:* Justin Pogacnik
>> *Cc:* petsc-users at mcs.anl.gov
>> *Subject:* Re: [petsc-users] PetscFECreateDefault in Fortran
>>
>> On Wed, May 31, 2017 at 10:00 PM, Justin Pogacnik <
>> j.pogacnik at auckland.ac.nz> wrote:
>>
>>> Thanks Matt! That works perfectly now. I have another question regarding
>>> accessing the quadrature information.
>>>
>>>
>>> When I use PetscFEGetQuadrature(), then PetscQuadratureView(), I see
>>> what I expect regarding point locations, weights.
>>>
>>>
>>> However, when I try to use PetscQuadratureGetData() the pointers seem to
>>> point to random memory locations.
>>>
>>>
>>> The exact line from my test problem is: call
>>> PetscQuadratureGetData(quad,q_nc,q_dim,q_num,pq_points,pq_weights,ierr);
>>>
>>> where the pq_* are the pointers giving strange output. The q_nc, q_dim,
>>> and q_num are all giving what I would expect to see.
>>>
>> You are clearly the first Fortran user interested in this stuff ;)
>> Handling of arrays in Fortran demands some more work
>> from us. I need to write a wrapper for that function. I will do it as
>> soon as I can.
>>
>>   Thanks,
>>
>>     Matt
>>
>>> Happy to send along the file if that helps.
>>>
>>>
>>> Thanks again,
>>>
>>>
>>> Justin
>>> ------------------------------
>>> *From:* Matthew Knepley <knepley at gmail.com>
>>> *Sent:* Thursday, June 1, 2017 1:34 AM
>>> *To:* Justin Pogacnik
>>> *Cc:* petsc-users at mcs.anl.gov
>>> *Subject:* Re: [petsc-users] PetscFECreateDefault in Fortran
>>>
>>> On Wed, May 31, 2017 at 7:53 AM, Matthew Knepley <knepley at gmail.com>
>>> wrote:
>>>
>>>> On Tue, May 30, 2017 at 10:19 PM, Justin Pogacnik <
>>>> j.pogacnik at auckland.ac.nz> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I'm developing a finite element code in fortran 90. I recently updated
>>>>> my PETSc and am now getting the following error during compile/linking on
>>>>> an existing application:
>>>>>
>>>>> Undefined symbols for architecture x86_64:
>>>>>
>>>>>   "_petscfecreatedefault_", referenced from:
>>>>>
>>>>>       _MAIN__ in fe_test.o
>>>>>
>>>>> ld: symbol(s) not found for architecture x86_64
>>>>>
>>>>> collect2: error: ld returned 1 exit status
>>>>>
>>>>> make: *** [dist/fe_test] Error 1
>>>>>
>>>>>
>>>>> I'm running Mac OS X Yosemite (10.10.5). I've created a "minimum
>>>>> working example" (attached) that re-creates the problem. It's basically
>>>>> just dm/impls/plex/examples/tutorials/ex3f90, but tries to create a
>>>>> PetscFE object. Everything goes fine and the DM looks like what is expected
>>>>> if PetscFECreateDefault is commented out. Any idea what am I missing?
>>>>>
>>>> Yes, I had not made a Fortran binding for this function. I will do it
>>>> now.
>>>>
>>>
>>> I have merged it to the 'next' branch, and it will be in 'master' soon.
>>>
>>>   Thanks,
>>>
>>>      Matt
>>>
>>>
>>>>   Thanks,
>>>>
>>>>      Matt
>>>>
>>>>
>>>>> Many thanks!
>>>>>
>>>>> Justin
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> 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
>>>>
>>>> http://www.caam.rice.edu/~mk51/
>>>>
>>>
>>>
>>>
>>> --
>>> 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
>>>
>>> http://www.caam.rice.edu/~mk51/
>>>
>>
>>
>>
>> --
>> 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
>>
>> http://www.caam.rice.edu/~mk51/
>>
>
>
>
> --
> 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
>
> http://www.caam.rice.edu/~mk51/
>



-- 
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

http://www.caam.rice.edu/~mk51/
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