[petsc-users] ODE solving

[Matthew Knepley]

On Thu, Oct 21, 2010 at 4:46 PM, Xuan Yu <xxy113 at psu.edu> wrote:

> Hi
>
>
> I am using Petsc solve ODE nonlinear problem.
>
> I was told to use direct method: umfpackage because of the jacobian matrix
> is 1860 by 1860.
>
> But the time consumption is still too big:
>
> TSSetType(ts,TSBEULER)
>
> time ./pihm -log_summary -ksp_type preonly -pc_type lu
> -pc_factor_mat_solver_package umfpack
>
> I got the result:
>
>
> When I use TSSetType(ts,TSSUNDIALS), it is fast:
>
>
>
> How can I find the reason why BEULER is so slow?
>

You SNES is not converging. You solve 163 systems, but do 4300 function
evaluations.

   Matt


> Thanks
>
> Xuan
>
>
>
>


-- 
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
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