//-----------------------------------------------------------------------------
bool DirichletBC::on_facet(const double* coordinates, const Facet& facet) const
{
// Check if the coordinates are on the same line as the line segment
if (facet.dim() == 1)
{
// Create points
Point p(coordinates[0], coordinates[1]);
const Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
const Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
// Create vectors
const Point v01 = v1 - v0;
const Point vp0 = v0 - p;
const Point vp1 = v1 - p;
// Check if the length of the sum of the two line segments vp0 and
// vp1 is equal to the total length of the facet
if ( std::abs(v01.norm() - vp0.norm() - vp1.norm()) < DOLFIN_EPS )
return true;
else
return false;
}
// Check if the coordinates are in the same plane as the triangular
// facet
else if (facet.dim() == 2)
{
// Create points
const Point p(coordinates[0], coordinates[1], coordinates[2]);
const Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
const Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
const Point v2 = Vertex(facet.mesh(), facet.entities(0)[2]).point();
// Create vectors
const Point v01 = v1 - v0;
const Point v02 = v2 - v0;
const Point vp0 = v0 - p;
const Point vp1 = v1 - p;
const Point vp2 = v2 - p;
// Check if the sum of the area of the sub triangles is equal to
// the total area of the facet
if (std::abs(v01.cross(v02).norm() - vp0.cross(vp1).norm()
- vp1.cross(vp2).norm() - vp2.cross(vp0).norm()) < DOLFIN_EPS)
{
return true;
}
else
return false;
}
dolfin_error("DirichletBC.cpp",
"determine if given point is on facet",
"Not implemented for given facet dimension");
return false;
}
//-----------------------------------------------------------------------------
bool NewDirichletBC::onFacet(real* coordinates, Facet& facet)
{
// Check if the coordinates are on the same line as the line segment
if ( facet.dim() == 1 )
{
// Create points
Point p(coordinates[0], coordinates[1]);
Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
// Create vectors
Point v01 = v1 - v0;
Point vp0 = v0 - p;
Point vp1 = v1 - p;
// Check if the length of the sum of the two line segments vp0 and vp1 is
// equal to the total length of the facet
if ( std::abs(v01.norm() - vp0.norm() - vp1.norm()) < DOLFIN_EPS )
return true;
else
return false;
}
// Check if the coordinates are in the same plane as the triangular facet
else if ( facet.dim() == 2 )
{
// Create points
Point p(coordinates[0], coordinates[1], coordinates[2]);
Point v0 = Vertex(facet.mesh(), facet.entities(0)[0]).point();
Point v1 = Vertex(facet.mesh(), facet.entities(0)[1]).point();
Point v2 = Vertex(facet.mesh(), facet.entities(0)[2]).point();
// Create vectors
Point v01 = v1 - v0;
Point v02 = v2 - v0;
Point vp0 = v0 - p;
Point vp1 = v1 - p;
Point vp2 = v2 - p;
// Check if the sum of the area of the sub triangles is equal to the total
// area of the facet
if ( std::abs(v01.cross(v02).norm() - vp0.cross(vp1).norm() - vp1.cross(vp2).norm()
- vp2.cross(vp0).norm()) < DOLFIN_EPS )
return true;
else
return false;
}
error("Unable to determine if given point is on facet (not implemented for given facet dimension).");
return false;
}
//-----------------------------------------------------------------------------
void BoundaryComputation::reorder(std::vector<std::size_t>& vertices,
const Facet& facet)
{
// Get mesh
const Mesh& mesh = facet.mesh();
// Get the vertex opposite to the facet (the one we remove)
std::size_t vertex = 0;
const Cell cell(mesh, facet.entities(mesh.topology().dim())[0]);
for (std::size_t i = 0; i < cell.num_entities(0); i++)
{
bool not_in_facet = true;
vertex = cell.entities(0)[i];
for (std::size_t j = 0; j < facet.num_entities(0); j++)
{
if (vertex == facet.entities(0)[j])
{
not_in_facet = false;
break;
}
}
if (not_in_facet)
break;
}
const Point p = mesh.geometry().point(vertex);
// Check orientation
switch (mesh.type().cell_type())
{
case CellType::interval:
// Do nothing
break;
case CellType::triangle:
{
dolfin_assert(facet.num_entities(0) == 2);
const Point p0 = mesh.geometry().point(facet.entities(0)[0]);
const Point p1 = mesh.geometry().point(facet.entities(0)[1]);
const Point v = p1 - p0;
const Point n(v.y(), -v.x());
if (n.dot(p0 - p) < 0.0)
{
const std::size_t tmp = vertices[0];
vertices[0] = vertices[1];
vertices[1] = tmp;
}
}
break;
case CellType::tetrahedron:
{
dolfin_assert(facet.num_entities(0) == 3);
const Point p0 = mesh.geometry().point(facet.entities(0)[0]);
const Point p1 = mesh.geometry().point(facet.entities(0)[1]);
const Point p2 = mesh.geometry().point(facet.entities(0)[2]);
const Point v1 = p1 - p0;
const Point v2 = p2 - p0;
const Point n = v1.cross(v2);
if (n.dot(p0 - p) < 0.0)
{
const std::size_t tmp = vertices[0];
vertices[0] = vertices[1];
vertices[1] = tmp;
}
}
break;
default:
{
dolfin_error("BoundaryComputation.cpp",
"reorder cell for extraction of mesh boundary",
"Unknown cell type (%d)",
mesh.type().cell_type());
}
}
}
