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A class providing numerical quadrature for faces. More...
#include <FaceQuadrature.hpp>
Public Member Functions | |
FaceQuadrature (const UnstructuredGrid &grid, const int face, const int degree) | |
int | numQuadPts () const |
void | quadPtCoord (const int index, double *coord) const |
double | quadPtWeight (const int index) const |
A class providing numerical quadrature for faces.
In general: \int_{face} g(x) dx = \sum_{i=0}^{n-1} w_i g(x_i). Note that this class does multiply weights by face area, so weights always sum to face area.
Degree 1 method: Midpoint (centroid) method. n = 1, w_0 = face area, x_0 = face centroid
Degree 2 method for 2d: Simpson's method (actually this is degree 3).
Degree 2 method for 3d: Based on subdivision of the face into triangles, with the centroid as a common vertex, and the triangle edge midpoint rule. Triangle i consists of the centroid C, nodes N_i and N_{i+1}. Its area is A_i. n = 2 * nn (nn = num nodes in face) For i = 0..(nn-1): w_i = 1/3 A_i. w_{nn+i} = 1/3 A_{i-1} + 1/3 A_i x_i = (N_i + N_{i+1})/2 x_{nn+i} = (C + N_i)/2 All N and A indices are interpreted cyclic, modulus nn.