----- Original Message ----- From: "Stas Fomin" <[EMAIL PROTECTED]> To: "Boost mailing list" <[EMAIL PROTECTED]> Sent: Monday, December 02, 2002 9:31 PM Subject: Re: [boost] UBLAS: preserving matrix resize.
> 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"; I understand. This is probably a bug in the 1_29_0 release: I've just tested that change against the CVS version and see the same results as in the dense case. > > > 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 :(. Sorry for inconvenience. If you upgrade to the CVS version, you may also consider to use the new coordinate_matrix implementing Fortran COO storage layout. > Also I plan to use uBLAS in some linear programming algorithms, > so adding/deleting rows/columns in sparse matrices will be very desirable... Regards Joerg _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
