/usr/include/dune/localfunctions/lagrange/q1/q1localbasis.hh is in libdune-localfunctions-dev 2.5.0-2.
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 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_Q1_LOCALBASIS_HH
#define DUNE_Q1_LOCALBASIS_HH
#include <numeric>
#include <dune/common/fmatrix.hh>
#include <dune/localfunctions/common/localbasis.hh>
namespace Dune
{
/**@ingroup LocalBasisImplementation
\brief Lagrange shape functions of order 1 on the reference cube.
Also known as \f$Q^1\f$.
\tparam D Type to represent the field in the domain.
\tparam R Type to represent the field in the range.
\tparam dim Dimension of the cube
\nosubgrouping
*/
template<class D, class R, int dim>
class Q1LocalBasis
{
public:
typedef LocalBasisTraits<D,dim,Dune::FieldVector<D,dim>,R,1,Dune::FieldVector<R,1>,
Dune::FieldMatrix<R,1,dim> > Traits;
//! \brief number of shape functions
unsigned int size () const
{
return 1<<dim;
}
//! \brief Evaluate all shape functions
inline void evaluateFunction (const typename Traits::DomainType& in,
std::vector<typename Traits::RangeType>& out) const
{
out.resize(size());
for (size_t i=0; i<size(); i++) {
out[i] = 1;
for (int j=0; j<dim; j++)
// if j-th bit of i is set multiply with in[j], else with 1-in[j]
out[i] *= (i & (1<<j)) ? in[j] : 1-in[j];
}
}
//! \brief Evaluate Jacobian of all shape functions
inline void
evaluateJacobian (const typename Traits::DomainType& in, // position
std::vector<typename Traits::JacobianType>& out) const // return value
{
out.resize(size());
// Loop over all shape functions
for (size_t i=0; i<size(); i++) {
// Loop over all coordinate directions
for (int j=0; j<dim; j++) {
// Initialize: the overall expression is a product
// if j-th bit of i is set to -1, else 1
out[i][0][j] = (i & (1<<j)) ? 1 : -1;
for (int k=0; k<dim; k++) {
if (j!=k)
// if k-th bit of i is set multiply with in[j], else with 1-in[j]
out[i][0][j] *= (i & (1<<k)) ? in[k] : 1-in[k];
}
}
}
}
/** \brief Evaluate partial derivatives of any order of all shape functions
* \param order Order of the partial derivatives, in the classic multi-index notation
* \param in Position where to evaluate the derivatives
* \param[out] out Return value: the desired partial derivatives
*/
void partial(const std::array<unsigned int,dim>& order,
const typename Traits::DomainType& in,
std::vector<typename Traits::RangeType>& out) const
{
auto totalOrder = std::accumulate(order.begin(), order.end(), 0);
if (totalOrder == 0) {
evaluateFunction(in, out);
}
else if (totalOrder == 1) {
out.resize(size());
auto direction = std::distance(order.begin(), std::find(order.begin(), order.end(), 1));
if (direction >= dim) {
DUNE_THROW(RangeError, "Direction of partial derivative not found!");
}
// Loop over all shape functions
for (std::size_t i = 0; i < size(); ++i) {
// Initialize: the overall expression is a product
// if j-th bit of i is set to -1, else 1
out[i] = (i & (1<<direction)) ? 1 : -1;
for (int k = 0; k < dim; ++k) {
if (direction != k)
// if k-th bit of i is set multiply with in[j], else with 1-in[j]
out[i] *= (i & (1<<k)) ? in[k] : 1-in[k];
}
}
}
else
{
DUNE_THROW(NotImplemented, "To be implemented!");
}
}
//! \brief Polynomial order of the shape functions
unsigned int order () const
{
return 1;
}
};
}
#endif
|