Re: [ublas] Simple problem with LU-decomposition (run-time assertion in function lu_factorize).

From: é×ÏÌÇÉÎ áÒÄÁÌÉÏÎ (comaMM_at_[hidden])
Date: 2008-08-22 17:18:15

Nope. I get a run-time assertion from function lu_factorize. Besides that I tried different matrixes.

Anyway. Thanks for the reaction.)

> Karl Meerbergen wrote:
> Hi,
> I guess your matrix is
> 1 2 3
> 4 5 6
> 7 8 9
> This is a singular matrix. You can do a factorization but not a solve 
> afterwards.
> Best regards,
> Karl
> ??????? ???????? wrote:
> > Hello, everybody!
> >
> > I found a page about LU-decomposition on Effective uBLAS wiki. Everything looked neat, and I decided to write simple example like this below:
> >
> > #include <boost/numeric/ublas/io.hpp>
> > #include <boost/numeric/ublas/lu.hpp>
> >
> > using namespace boost::numeric::ublas;
> >
> > int main () {
> > matrix<int> A(3,3), B(identity_matrix<int>(3));
> > for (int i=0; i<3; ++i)
> > for (int j=0; j<3; ++j)
> > A(i,j)=3*i+j+1;
> > 
> > std::cout << A << std::endl;
> > std::cout << B << std::endl;
> > 
> > permutation_matrix<> pm(3);
> > 
> > lu_factorize<matrix<int>, permutation_matrix<> >(A, pm);
> > lu_substitute(A, pm, B);
> > 
> > std::cout << A << std::endl;
> > std::cout << B << std::endl;
> > 
> > return EXIT_SUCCESS;
> > }
> >
> > But when I try to run the compiled executable, I got a run-time assertion with this text:
> >
> > Check failed in .../include/boost/numeric/ublas/lu.hpp at line 157:
> > singular != 0 || detail::expression_type_check (prod (triangular_adaptor<matrix_type, unit_lower> (m), triangular_adaptor<matrix_type, upper> (m)), cm)
> >
> > Maybe someone had already faced this problem?
> >
> > P.S. On the page about LU-decomposition there was something about getting recent version of lu.hpp from Boost CVS. But the link in Boost::uBLAS documentation seems to be broken.
> >
> > P.P.S. I have: MS Windows Vista 32-bit with MinGW g++ 3.4.5 compiler. (Boost version is 1.36.0).