basis (7rheolef)

The basis class defines functions that evaluates a polynomial basis and its derivatives on a point. The polynomial basis is designated by a string, e.g. "P0", "P1", "P2", "bubble",... indicating the basis. The basis depends also of the reference element: triangle, square, tetrahedron (see reference_element(2)). For instance, on a square, the "P1" string designates the common Q1 four-nodes basis on the reference square.

The nodes associated to the Lagrange polynomial basis are also available by its associated accessor.

The basis class is a see smart_pointer(2)) class on a basis_rep class that is a pure virtual base class for effective bases, e.g. basis_P1, basis_P1, etc.

template<class T>
class basis_basic : public smart_pointer<basis_rep<T> > {
public:

// typedefs:

    typedef basis_rep<T>                           rep;
    typedef smart_pointer<rep>                     base;
    typedef typename basis_rep<T>::size_type       size_type;

// allocators:

    basis_basic (std::string name = "");

// accessors:

    std::string name() const;
    size_type   degree() const;
    size_type   size (reference_element hat_K) const;

    void hat_node(
        reference_element              hat_K,
        std::vector<point_basic<T> >&  hat_node) const;
    void hat_node(
        reference_element                               hat_K,
        typename std::vector<point_basic<T> >::iterator hat_node) const;

    void eval(
        reference_element     hat_K,
        const point_basic<T>& hat_x,
        std::vector<T>&       values) const;
    void eval(
        reference_element                 hat_K,
        const point_basic<T>&             hat_x,
        typename std::vector<T>::iterator values) const;

    void grad_eval(
        reference_element    hat_K,
        const point_basic<T>&         hat_x,
        std::vector<point_basic<T> >&  values) const;
    void grad_eval(
        reference_element                               hat_K,
        const point_basic<T>&                           hat_x,
        typename std::vector<point_basic<T> >::iterator values) const;
};
typedef basis_basic<Float> basis;

reference_element(2), smart_pointer(2)