/usr/include/dune/localfunctions/dualmortarbasis/dualq1/dualq1localinterpolation.hh is in libdune-localfunctions-dev 2.4.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_DUAL_Q1_LOCALINTERPOLATION_HH
#define DUNE_DUAL_Q1_LOCALINTERPOLATION_HH
#include <array>
#include <vector>
#include <dune/common/fvector.hh>
#include <dune/common/fmatrix.hh>
namespace Dune
{
/** \todo Please doc me! */
template<int dim, class LB>
class DualQ1LocalInterpolation
{
public:
void setCoefficients(const std::array<Dune::FieldVector<typename LB::Traits::RangeFieldType, (1<<dim)> ,(1<<dim)>& coefficients)
{
coefficients_ = coefficients;
}
//! \brief Local interpolation of a function
template<typename F, typename C>
void interpolate (const F& f, std::vector<C>& out) const
{
typename LB::Traits::DomainType x;
typename LB::Traits::RangeType y;
const int size = 1<<dim;
// compute Q1 interpolation coefficients
Dune::FieldVector<C,size> q1Coefficients;
for (int i=0; i< (1<<dim); i++) {
// Generate coordinate of the i-th corner of the reference cube
// We could use the ReferenceElement for this as well, but it is
// still not clear how dune-localfunctions should have access to them.
for (int j=0; j<dim; j++)
x[j] = (i & (1<<j)) ? 1.0 : 0.0;
f.evaluate(x,y); q1Coefficients[i] = y;
}
out.resize(size);
// solve a linear system to compute the dual coefficients
Dune::FieldMatrix<C,size,size> mat;
for (int i=0; i<size; i++)
for (int j=0; j<size; j++)
mat[i][j] = coefficients_[j][i];
// now solve for the weights
Dune::FieldVector<C,size> sol(0);
mat.solve(sol,q1Coefficients);
// write result in out vector
for (int i=0; i<size; i++)
out[i] = sol[i];
}
private:
std::array<Dune::FieldVector<typename LB::Traits::RangeFieldType, (1<<dim)> ,(1<<dim)> coefficients_;
};
}
#endif
|