[petsc-users] Field split questions

[Barry Smith]

  Well the field split stuff in 3.1 is rather iffy anyways.   You really need to take the couple hours and do the upgrade before trying to add new features to the fortran code you are using.  The time to upgrade will be much less than time spent in work arounds.

    Barry

On Aug 8, 2012, at 8:52 PM, Colin McAuliffe <cjm2176 at columbia.edu> wrote:

> Is there an alternative to this routine that will allow me to define hierarchical field splits in 3.1p8? It will be a fairly significant undertaking to upgrade the fortran code I am using to be compatible with newer versions of petsc.
> 
> Colin
> 
> Quoting Barry Smith <bsmith at mcs.anl.gov>:
> 
>> 
>>   Colin,
>> 
>>    I'm sorry we never had a FORTRAN interface for this routine.  You'll need to switch to petsc-dev  http://www.mcs.anl.gov/petsc/developers/index.html to use that  function.
>> 
>>    Barry
>> 
>> 
>> On Aug 8, 2012, at 7:54 PM, Colin McAuliffe <cjm2176 at columbia.edu> wrote:
>> 
>>> Thanks I will look into DM. Is PCFieldSplitGetSubKSP in petsc  version 3.1p8 callable from fortran? I am getting the following  error when I compile the fortran code, and I cant figure out if  this is an error in my code or what.
>>> 
>>> Undefined symbols for architecture x86_64:
>>> "_pcfieldsplitgetsubksp_", referenced from:
>>>     _umacr6_ in umacr6.o
>>> ld: symbol(s) not found for architecture x86_64
>>> 
>>> 
>>> thanks
>>> Colin
>>> 
>>> 
>>> Quoting Matthew Knepley <knepley at gmail.com>:
>>> 
>>>> On Wed, Aug 8, 2012 at 8:48 AM, Colin McAuliffe  <cjm2176 at columbia.edu>wrote:
>>>> 
>>>>> Hello all,
>>>>> 
>>>>> When using PCFieldSplitSetIS to define splits within splits, should the IS
>>>>> contain indices in the original matrix or in the next highest split level?
>>>>> 
>>>> 
>>>> The next highest split level. You might consider using a DM if you have
>>>> some structure (like discretization on a mesh).
>>>> This should handle all the index-wrangling for you. It is new, but intended
>>>> for just this kind of thing.
>>>> 
>>>> Also, my matrix is in aij format but one of the sub fields has a block
>>>>> diagonal structure. Is it still possible use block jacobi on this field?
>>>>> 
>>>> 
>>>> Yes.
>>>> 
>>>>  Matt
>>>> 
>>>> 
>>>>> Thanks and all the best
>>>>> Colin
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> --
>>>>> Colin McAuliffe
>>>>> PhD Candidate
>>>>> Columbia University
>>>>> Department of Civil Engineering and Engineering Mechanics
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> --
>>>> 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
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> Colin McAuliffe
>>> PhD Candidate
>>> Columbia University
>>> Department of Civil Engineering and Engineering Mechanics
>> 
>> 
>> 
> 
> 
> 
> -- 
> Colin McAuliffe
> PhD Candidate
> Columbia University
> Department of Civil Engineering and Engineering Mechanics