[Trilinos-Users] ILU IFPACK preconditioner

[Lucia Mirabella]

Mike,

thanks for your answer. I've just tried your suggestion, but I get a 
segmentation fault at runtime when I try to extract the L factor.

Do you know what causes this problem?

Thank you,

Lucia




Heroux, Michael A wrote:
> Lucia,
>
> The class Ifpack_Preconditioner does not have a method called L(). 
> Although the factory you are using actually creates an Ifpack_ILU 
> object, it is cast back to its base class Ifpack_Preconditioner. In 
> order to get access to L, you will want to use a dynamic cast to 
> downcast to the Ifpack_ILU object and then use the L() accessor method 
> after that. The following code is approximately what you need:
>
> Ifpack_ILU * iluPrec = dynamic_cast<Ifpack_ILU *>(&*Prec);
> Epetra_CrsMatrix L_factor = iluPrec->L();
>
> Mike
>
>
> On 10/27/08 2:23 PM, "Lucia Mirabella" <lucia at mathcs.emory.edu> wrote:
>
>     Hi,
>
>     I am encountering a problem while trying to extract L and U
>     factors from
>     ILU IFPACK preconditioner.
>
>     In my code I have a RCP pointer to an Ifpack_Preconditioner object
>     that
>     is initialized using the Create method of an Ifpack object (with "ILU"
>     as preconditioner type argument).
>
>     "Ifpack Factory;
>     RCP<Ifpack_Preconditioner> Prec;
>     Prec = Teuchos::rcp( Factory.Create("ILU", &*B_rcp, OverlapLevel) );"
>
>
>     When I invoke the method L() on the Ifpack_Preconditioner object
>
>     "Epetra_CrsMatrix L_factor= Prec->L();"
>
>     I get this compiling error:
>
>     "error: ‘class Ifpack_Preconditioner’ has no member named ‘L’"
>
>     Could you please suggest me how to solve this problem?
>
>     Thank you,
>
>     Lucia Mirabella
>
>
>
>
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