[petsc-users] application of petsc to psr

Jed Brown jedbrown at mcs.anl.gov
Sat May 5 16:18:59 CDT 2012


With PETSc, there is a lot more opportunity to change details of the
nonlinear and linear solve. You can use CVode through PETSc, but it may
also be worth trying the ARK-IMEX and Rosenbrock-W methods that we have
implemented, especially if stability near the imaginary axis is useful for
you, or if error control is being finnicky with the BDFs. It is easier to
experiment with different algorithms in PETSc since most choices can be
made at run-time (e.g. command line options).

> On May 4, 2012 6:38 PM, "Alan Sayre" <ansayre at sbcglobal.net> wrote:
>>
>> Barry,
>>
>> Sorry for being imprecise. I haven't started coding anything yet with
PETSc. I have only tried the native SUNDIALS Kinsol. I have had good
success using the SUNDIALS Cvode for zero-d ode using the ABF mechanism. My
purpose in posting is to determine if the PETSc suite of tools is
appropriate, there is experience using solving similar problems, etc.
>>
>> Thanks,
>>
>> Alan
>>
>> ________________________________
>> From: Barry Smith <bsmith at mcs.anl.gov>
>> To: PETSc users list <petsc-users at mcs.anl.gov>
>> Sent: Fri, May 4, 2012 7:06:33 PM
>> Subject: Re: [petsc-users] application of petsc to psr
>>
>>
>>   Alan,
>>
>>     You have a very complicated model (and presumably discretization)
which makes it difficult for us to provide coherent advice. What stage are
you in your code at using PETSc? Are you thinking about using PETSc?  Have
you not started yet? Is it running but not converging with PETSc?  There
are many reasons that Newton may not converge: see
http://www.mcs.anl.gov/petsc/documentation/faq.html#newton
>>
>>   Barry
>>
>>
>>
>> On May 3, 2012, at 8:02 PM, Alan Sayre wrote:
>>
>> > Barry,
>> >
>> > Thanks but that is not quite what I have in mind. The existing PSR
model in my CFD code is not converging for PSR models containing the Method
of Moments using the ABF mechanism described as shown in the Chemkin 2006
workshop proceedings. I have tried KINSOL and have still not been able to
get it to converge. Any assistance in developing a PETSC based solution
algorithm is appreciated.
>> >
>> > thanks,
>> >
>> > Alan
>> >
>> > From: Barry Smith <bsmith at mcs.anl.gov>
>> > To: PETSc users list <petsc-users at mcs.anl.gov>
>> > Sent: Wed, May 2, 2012 10:54:21 PM
>> > Subject: Re: [petsc-users] application of petsc to psr
>> >
>> >
>> >
http://www.sandia.gov/chemkin/workshop/proceedings/Meeks_CHEMKINWorkshop2006.pdf
?
>> >
>> >
>> > On May 2, 2012, at 9:45 PM, Alan Sayre wrote:
>> >
>> > > I'm new to using PETSc. I need to model perfectly stirred reactors
for chemical kinetics (10-1000 species), I welcome recommendations on how
to get "up-to-speed". I also need to incorprate solution of the energy
(temperature) equation and moments of soot distributions.
>> > >
>> > > Thanks for any suggestions.
>> > >
>> > > Alan
>> >
>>
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