double bndIntegration(const pointSet& mesh, const scalarField& sf, int bnd)
{
double sum = 0.0;
int n = mesh.getNbBndPoints();
int n1, n2;
double dx;
for (int i=0; i<n; i++)
{
if (mesh.getBND(i) == bnd)
{
mesh.findLeftRightBndPoint(i, n1, n2);
// Check first neighbour
if (n1 > i)
{
dx = mesh.dist(i,n1);
sum += 0.5*(sf(i)+sf(n1)) * dx;
}
if (n2 > i)
{
dx = mesh.dist(i,n2);
sum += 0.5*(sf(i)+sf(n2)) * dx;
}
}
}
return sum;
}
void approximatedNormals(const pointSet& mesh, vector<int> neighb, int pnb, double& nx_out, double& ny_out)
{
if (mesh.getBND(pnb)==0)
throw mfpmExcept(0);
int NP = neighb.size();
double sl2 = mesh.getSL(pnb);
// New approach
double sumX = 0, sumY = 0;
double nx, ny;
int count = 0;
for (int i=0; i<NP; i++)
{
if (pnb!=neighb[i] )
{
nx = (mesh.y(pnb)-mesh.y(neighb[i]));
ny = -(mesh.x(pnb)-mesh.x(neighb[i]));
double weight = exp(-5.0* (nx*nx+ny*ny) / sl2);
double length = sqrt(nx*nx+ny*ny);
nx /= length;
ny /= length;
if ( nx*mesh.getNormal(0,pnb) + ny*mesh.getNormal(1,pnb) < 0)
{
nx *= -1.0;
ny *= -1.0;
}
sumX += nx*weight;
sumY += ny*weight;
}
}
sumX /= NP-1;
sumY /= NP-1;
double length = sqrt(sumX*sumX+sumY*sumY);
if (length==0)
throw mfpmExcept(1000);
nx_out = sumX / length;
ny_out = sumY / length;
}