Dear P. Berger,

No, there is no specific function in Gmm to compute the orthonormal
basis for the range of a matrix. (There is a function which is
range_basis in gmm_range_basis.h but it is for large sparse matrices and
this extract only a basis, it do not perform an orthogonalization).

The class in gmm_modified_gram_schmidt.h header is mainly used by gmres
algorithm. It works on a dense matrix.
The function "orthogonalize" performs the ortogonalization of the vector
number i, storing the scalar  products in a vector Hi. This means that
before calling "orthogonalize" you need to fill the vectors V[i] of the
object  modified_gram_schmidt. This is really adapted to the gmres
algorithm. Probably, in your case, it is simpler to just copy the loop
of the function orthogonalize than using the modified_gram_schmidt object.

Yves.


Le 18/09/2013 18:26, Philipp Berger a écrit :
> To whom it may concern,
>
> sorry for asking something of such simple nature, but I can not figure
> it out on my own.
>
> Is GMM able to calculate the orthonormal basis for the range of a
> matrix? Something like "orth()" in Matlab (
> http://www.mathworks.de/help/matlab/ref/orth.html
> <http://www.mathworks.de/de/help/matlab/ref/orth.html> ).
> I found the gmm_modified_gram_schmidt header, which seems to be what I
> want but since there is no documentation on the functions I find
> myself unable to understand how they are meant to be applied.
>
> For example, given a matrix M:
> gmm::row_matrix<gmm::wsvector<double>> M1;
> M1.resize(4,4);
> // Insert some data
>
> And now I would like to get a matrix containg the orthonormal base of M1.
>
> Thank you for your time,
>
> P. Berger
>
>
> _______________________________________________
> Getfem-users mailing list
> [email protected]
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-- 

  Yves Renard ([email protected])       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA-Lyon             fax : (33) 04.72.43.85.29
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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