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Ublas : |
From: Wenming Yu (xuebuyu_at_[hidden])
Date: 2006-02-22 22:04:44
Hello,
Ok, I see. Thanks a lot.
Wenming Yu
-----Original Message-----
From: ublas-bounces_at_[hidden] [mailto:ublas-bounces_at_[hidden]]
On Behalf Of Karl Meerbergen
Sent: Wednesday, February 22, 2006 10:46 PM
To: ublas mailing list
Subject: Re: [ublas] solving non triangular systems
Hello,
You have to checkout boost-sandbox:
cvs -z3 -d:pserver:anonymous_at_[hidden]:/cvsroot/boost-sandbox
co boost-sandbox
and add boost-sandbox to your include path.
Hope this is OK.
Karl
Wenming Yu wrote:
>Hi£¬
> But I haven't found subfolder "bindings" in boost/numeric. I use VC
>.net.
>What's wrong? Thanks.
>
>Wenming Yu
>
>-----Original Message-----
>From: ublas-bounces_at_[hidden] [mailto:ublas-bounces_at_[hidden]]
>On Behalf Of Karl Meerbergen
>Sent: Wednesday, February 22, 2006 9:16 PM
>To: ublas mailing list
>Subject: Re: [ublas] solving non triangular systems
>
>Hello,
>
>You could use the ublas code, which is easy to use. A bit more
>complicated but probably more performant is the use of LAPACK using the
>boost-sandbox bindings:
>
>#include <boost/numeric/bindings/lapack/gesv.hpp>
>#include <boost/numeric/bindings/traits/ublas_matrix.hpp>
>#include <boost/numeric/bindings/traits/ublas_vector2.hpp>
>
>matrix<double, column_major> A(n,n) ; // very important that it is
>column_major
>vector<double> b(n);
>vector<double> x(n);
>
>...
>
>x = b ;
>boost::numeric::bindings::lapack::gesv(A,x) ;
>
>
>Karl
>
>
>
>Gunter Winkler wrote:
>
>
>
>>On Wednesday 22 February 2006 07:53, asaf david wrote:
>>
>>
>>
>>
>>>say i got a non triangular matrix M and a vector b, and i'd like to find
>>>the vector x such that Mx=b. is there any way to perform this ? because
>>>appearently there's only solver for triangular matrixes. btw i'm sorry if
>>>it has been answered before, i coudlnt find a search option in the
>>>
>>>
>archives
>
>
>>>
>>>
>>>
>>>
>>you should use the LU-factorization. The code is like this:
>>
>>// possibly some more ublas includes here
>>#include <boost/numeric/ublas/lu.hpp>
>>matrix<double> A(n,n);
>>vector<double> b(n);
>>vector<double> x(n);
>>permutation_matrix P(n);
>>
>>lu_factorize(A,P);
>>x = b;
>>lu_substitute(A,P,x);
>>
>>the x ist the solution of Ax=b.
>>
>>mfg
>>Gunter
>>_______________________________________________
>>ublas mailing list
>>ublas_at_[hidden]
>>http://lists.boost.org/mailman/listinfo.cgi/ublas
>>
>>
>>
>>
>>
>
>
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>ublas mailing list
>ublas_at_[hidden]
>http://lists.boost.org/mailman/listinfo.cgi/ublas
>
>
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