permutation.cc (flens/examples/permutation.cc)

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#include <cxxstd/cmath.h>

#include <cxxstd/iostream.h>

#include <flens/examples/permutation.h>

#include <flens/flens.cxx>

using namespace flens;

using namespace std;

int

main()

{

    typedef DenseVector<Array<double> >     RealDenseVector;

    typedef GeMatrix<FullStorage<double> >  RealGeMatrix;

    const int   n = 5;

    Permutation P(n);

    P.vector = 5, 3, 2, 1, 4;

    RealDenseVector                 x(5), y;

    x = 1, 2, 3, 4, 5;

    y = P*x;

    cout << "x = " << x << endl;

    cout << "y = P*x = " << y << endl;

    x = transpose(P)*y;

    cout << "x = P^T*y = " << x << endl;

    RealGeMatrix  I(n, n), B(n,n);

    I = 0;

    I.diag(0) = 1;

    B = P*I;

    cout << "B = P*I = " << B << endl;

}