[petsc-users] Profile a matrix-free solver.

Song Gao song.gao2 at mail.mcgill.ca
Fri Jan 15 14:58:20 CST 2016


It's on page 668 equation 4.6.


2016-01-15 15:39 GMT-05:00 Zou (Non-US), Ling <ling.zou at inl.gov>:

> Hi Song, I wonder if you have a reference paper on the preconditioning
> algorithm you are working on, i.e., using the 1st order flux for
> preconditioning purpose when your 'true' fluxes are evaluated using the 2nd
> order AUSM scheme.
> Best,
> Ling
> On Fri, Jan 15, 2016 at 1:34 PM, Song Gao <song.gao2 at mail.mcgill.ca>
> wrote:
>> Thanks. I'll try to improve "my code"
>> 2016-01-15 14:56 GMT-05:00 Jed Brown <jed at jedbrown.org>:
>>> Matthew Knepley <knepley at gmail.com> writes:
>>> > The way I read this, you are taking about 23 iterates/solve, and most
>>> of
>>> > your work is residual computation which should
>>> > be highly parallelizable/vectorizable. This seems great to me.
>>> This in the sense that it's up to you to determine whether your
>>> matrix-free residual and preconditioning code is fast.  This profile
>>> merely says that almost all of the run-time is in *your code*.  If your
>>> code is fast, then this is good performance.  If you can use a different
>>> algorithm to converge in fewer iterations, or a different representation
>>> to apply the operator faster, then you could do better.
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