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Ublas : |
From: Karl Meerbergen (Karl.Meerbergen_at_[hidden])
Date: 2005-05-27 05:43:07
On Thursday 26 May 2005 16:52, Paul C. Leopardi wrote:
> Dear Dan,
> Yes, you can use uBLAS to invert matrices, but this might not be the
> optimal way to do it. You use UBLAS to invert a matrix by doing solves on
> each column of a unit matrix.
> GluCat uses the uBLAS routines, originally because Joerg Walter wrote them
> specially for GluCat, and then because it was the easiest thing to do.
> Best regards
In general computing the inverse of a matrix is a very bad idea. It is very
expensive and numerically less relible than using a backtransformation. For a
sparse matrix, I am sure that SuperLU is a lot more efficient than the ublas
lu.
Have a nice day,
Karl
>
> On Thu, 26 May 2005 11:53 am, Dan Elliott wrote:
> > Paul C. Leopardi wrote:
> > >Dear Luca,
> > >Reply below. Best regards
> > >
> > >On Sun, 22 May 2005 02:46 am, luca regini wrote:
> > >>I am writing a scientific application. For the moment my vectors are
> > >> just dinamically allocated array of doubles.
> > >>To use UBLAS should i rewrite the code to use UBLAS' vector or is there
> > >> an adapter??
> > >>After performing some sparse matrix computations i must solve a system
> > >>using SuperLU. What's the state of
> > >>the driver?? How does the driver behave? Does it copy stuff and
> > >> allocate new memory??
> > >
> > >Have you tried using uBLAS lu_factorize and lu_substitute, defined in
> > > lu.h ? Do you know how it compares to SuperLU ? Has anyone made this
> > > comparison ? Also, how large are your sparse matrices?
> >
> > Does this mean we can invert uBLAS matrices using uBLAS routines. I was
> > under the impression we had to make use of an external library to solve.
> >
> > thanks.
> >
> > - dan
> > _______________________________________________
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> > ublas_at_[hidden]
> > http://lists.boost.org/mailman/listinfo.cgi/ublas
>
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