Re: [boost] UBLAS: preserving matrix resize.

From: Stas Fomin (stas_at_[hidden])
Date: 2002-12-02 15:31:01

    Thanks for the answer!

> > I have to make matrix resize with preserving of the content of the matrix.
> >  (add rows, columns...)
>
> I've just tested the following program under GCC 3.1:
>
> ----------
> #include <boost/numeric/ublas/vector.hpp>
....
>
> typedef ublas::matrix<double> Mat;

This sample works if "typedef ublas::matrix<double> Mat;"
and does not work with "typedef ublas::sparse_matrix<double,ublas::column_major> Mat";

> > 2. How to do "preserving matrix resize" efficiently?
>
> I.e. without copying/swapping? Why don't you start with your final matrix
> referencing the smaller sub matrices via matrix_range<>?

 This isn't clear to me. What do you mean?

 I write reading matrices from files in some sparsed formats (MatrixMarket, MPS).
I will implement one-pass reading, so the number of rows, columns and nonzeros
are not known in advance.
I use "sparse_matrix<double,column_major,std::map>" for fast random access,
and I will to know how implement "preserving matrix resize" efficiently.
The only way I found does not work :(.

Also I plan to use uBLAS in some linear programming algorithms,
so adding/deleting rows/columns in sparse matrices will be very desirable...

            Any ideas are welcomed...

                                Sincerely, Stas Fomin.