lapack-gesv.cc (flens/examples/lapack-gesv.cc)

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#include <cxxstd/iostream.h>

///

///  With header __flens.cxx__ all of FLENS gets included.

///

///  :links:  __flens.cxx__ -> file:flens/flens.cxx

#include <flens/flens.cxx>

using namespace std;

using namespace flens;

typedef double   T;

int

main()

{

    ///

    ///  Define some convenient typedefs for the matrix/vector types

    ///  of our system of linear equations.

    ///

    typedef GeMatrix<FullStorage<T> >           Matrix;

    typedef DenseVector<Array<T> >              Vector;

    ///

    ///  We also need an extra vector type for the pivots.  The type of the

    ///  pivots is taken for the system matrix.

    ///

    typedef Matrix::IndexType                   IndexType;

    typedef DenseVector<Array<IndexType> >      IndexVector;

    ///

    ///  Set up the baby problem ...

    ///

    const IndexType n = 4;

    Matrix         A(n,n);

    Vector         b(n);

    IndexVector    piv(n);

    A =  2,   3,  -1,   0,

        -6,  -5,   0,   2,

         2,  -5,   6,  -6,

         4,   6,   2,  -3;

    b = 20,

       -33,

       -43,

        49;

    cerr << "A = " << A << endl;

    cerr << "b = " << b << endl;

    ///

    /// And solve it with __lapack::sv__

    ///

    /// :links: __lapack::sv__ -> doc:flens/lapack/ge/sv

    lapack::sv(A, piv, b);

    cerr << "x = " << b << endl;

}