[petsc-dev] Fwd: Is there any example that allows time-integration provided by users

[Barry Smith]

On Dec 13, 2012, at 11:27 AM, Peter Brune <prbrune at gmail.com> wrote:

> An abandoned attempt at this lies dormant in src/snes/impls/multiblock.  We could try to revive it.

   Or at least give it a reasonable name :-(  like SNESFIELDSPLIT

> 
> - Peter
> 
> 
> On Thu, Dec 13, 2012 at 11:25 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> Yes, but even more than linear fieldsplit, there are _many_ variations, involving nonlinear change of basis and various types of elimination. I worry that it may be even more complicated and harder to use.
> 
> 
> On Thu, Dec 13, 2012 at 9:15 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> 
>   We could possibly provide the equivalent of PCFieldSplit for nonlinear problems?  These could be accelerated via the various non-linear accelerates or even via matrix-free Newton?
> 
> 
>    Barry
> 
> 
> Begin forwarded message:
> 
>> From: Jed Brown <jedbrown at mcs.anl.gov>
>> Subject: Re: Is there any example that allows time-integration provided by users
>> Date: December 13, 2012 11:06:29 AM CST
>> To: Lulu Liu <lulu.liu at kaust.edu.sa>, Barry Smith <bsmith at mcs.anl.gov>
>> 
>> It sounds like you want to do classical operator splitting (which is notoriously inaccurate). The literature on these methods is rife with special-purpose band-aids that I'd rather not try to support all of in PETSc.
>> 
>> My preference would be to write your method as an ARKIMEX, with "trivial" implicit part on the "part" of the equation that you wanted to treat explicitly, or if you wanted to solve both implicitly (but decoupled) then do the appropriate incomplete solve. Can you be more specific about what problem you want to solve?
>> 
>> 
>> On Wed, Dec 12, 2012 at 7:42 AM, Lulu Liu <lulu.liu at kaust.edu.sa> wrote:
>> There is two equations in my system, and I want solve the first one, and then solve the second equation. Is there any example that allows me to solve equations one by one?
>>  
>>  
>> I want to solve nonlinear system on every time level, but it is feasible if I could provide the time discretization schemes by myself. Is there any example about this?
>>  
>> Thank you!
>> 
>> -- 
>> Best wishes,
>> Lulu Liu
>> Applied Mathematics and Computational Science
>> King Abdullah University of Science and Technology
>> Tel：＋966－0544701599
>> 
>> 
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> 
> 
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