[petsc-users] Question for time dependent problems

[Lisandro Dalcin]

On 5 July 2011 17:35, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>> Beginning of a time step (1st implicit stage of RK scheme):
>> 1. Use MatZeroEntries on the preconditioner
>
>  Do not call MatZeroEntries on a freshly created matrix (that destroys the preallocation pattern) so skip the MatZeroEntries the first time.
>

What do you mean? The OP said that the nonzero structure was set at
problem set up.

-- 
Lisandro Dalcin
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