Re: [ublas] order of arguments in lu_substitute

From: Sorkin Dima (dsorkin_at_[hidden])
Date: 2006-10-27 09:25:20

On Tue, 24 Oct 2006, Gunter Winkler wrote:
> I suggest renaming the LU solves to
>
> lu_substitute(A,X,Y), lu_substitute(A,x,y) -> solve L(Ux)=y
> ul_substitute(A,X,Y), ul_substitute(A,x,y) -> U(Lx)=y
>
> (thus lu_substitute(X,A,Y) would then be ul_substitute(trans(A),X,Y),
> which is much clearer)

Hi.
1) I agree.
There are many variants of lu functions in lu.hpp,
with vector and matrix arguments, with pivoting and not.
If someone could give a one line description to what each one does,
I could take the technical work and submit a patch.

2) I have a compilation problem with lu_factorize, (boost 1.33),
when using it without pivoting. Gcc 4.0 is geting angry on:
ublas::matrix<double> A(2,2);
ublas::lu_factorize(A);

3) The 1.33 version of lu.hpp should have (if not already in CVS HEAD):
#include <boost/numeric/ublas/vector_proxy.hpp>
#include <boost/numeric/ublas/triangular.hpp>

Regards,
Dima.