Re: [Getfem-users] GMM++ Preconditioner

[Renard Yves]

Dear Danesh,

The template argument for the preconditionner is the matrix type. So  
you should declare

gmm::dense_matrix<double> A(100, 100);

filling the matrix

gmm::ilu_precond<gmm::dense_matrix<double> > P1(A);



Of course, this is not very satisfactory because an incomplete LU  
decomposition on a dense matrix is a complete LU decomposition. You  
should work with sparse matrices instead.

You can see on the following page of the documentation how to declare  
each preconditionner :

http://download.gna.org/getfem/html/homepage/gmm/iter.html#preconditioners

Yves.


Danesh Daroui <address@hidden> a écrit :

> Dear all,
>
> I would like to use GMM++ iterative solvers. The problem is that I can
> not use for example incomplete LU factorization preconditioner. Let say
> that I have the equation Ax=b. The I define the preconditioner as:
>
> gmm::dense_matrix<double> A(100, 100);
>
> // filling the matrix
>
> gmm::ilu_precond<double> P1(A);
>
> but I get compilation errors. It just compiled successfullt when I define:
>
> gmm::ilu_precond<double> P1;
>
> but there is no hint and neither sample code to show which function  
> should I call to create the preconditioner.
>
> Can anybody help?
>
> Regards,
>
> D.
>
>
>
>
>
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