[petsc-users] How to set up -mat_mumps_icntl13 1 in the code?

[Giacomo Mulas]

On Tue, 15 May 2012, Barry Smith wrote:

>> So, if I understand correctly, I am supposed to call
>> PetscOptionsInsertString() to add any options I want to have as defaults,
>> then what is the call PetscOptionsInsert() for?
>
>    It "resets" the options database with the command line options. If you
> did not call this then the InsertString() options would not be overwritten
> with the command line options.

Ah ok! It makes sense now that you explain. I could not quite understand
this from the man pages :(

>   Ignore the PetscOptionsSetFromOptions() it has nothing to do with
> anything there (it is just in that example to test it).  It does not
> affect the options data base entries.

So I can omit that. Good. However, I suspect this is not the case for the
similar slepc function EPSSetFromOptions(): I had to put that _after_ the
PetscOptionsInsertString() call, or inserted options would be ignored by
slepc. So I suppose the correct sequence should be:

PetscOptionsInsertString() # this adds my defaults
PetscOptionsInsert()       # this has command line options replace defaults
EPSSetFromOptions()        # this applies resulting options to my eps object

Is that right?

Thanks, bye
Giacomo

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Giacomo Mulas <gmulas at oa-cagliari.inaf.it>
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