//-----------------------------------------------------------------------------
void dolfin::p_refine(Mesh& refined_mesh, const Mesh& mesh)
{
MeshEditor editor;
if (mesh.geometry().degree() != 1)
{
dolfin_error("refine.cpp",
"increase polynomial degree of mesh",
"Currently only linear -> quadratic is supported");
}
const CellType::Type cell_type = mesh.type().cell_type();
if (cell_type != CellType::Type::triangle
and cell_type != CellType::Type::tetrahedron
and cell_type != CellType::Type::interval)
{
dolfin_error("refine.cpp",
"increase polynomial degree of mesh",
"Unsupported cell type");
}
const std::size_t tdim = mesh.topology().dim();
const std::size_t gdim = mesh.geometry().dim();
editor.open(refined_mesh, cell_type, tdim, gdim, 2);
// Copy over mesh
editor.init_vertices_global(mesh.num_entities(0), mesh.num_entities_global(0));
for (VertexIterator v(mesh); !v.end(); ++v)
editor.add_vertex(v->index(), v->point());
editor.init_cells_global(mesh.num_entities(tdim), mesh.num_entities_global(tdim));
std::vector<std::size_t> verts(tdim + 1);
for (CellIterator c(mesh); !c.end(); ++c)
{
std::copy(c->entities(0), c->entities(0) + tdim + 1, verts.begin());
editor.add_cell(c->index(), verts);
}
// Initialise edges
editor.init_entities();
// Add points at centres of edges
for (EdgeIterator e(refined_mesh); !e.end(); ++e)
editor.add_entity_point(1, 0, e->index(), e->midpoint());
editor.close();
}
//-----------------------------------------------------------------------------
UnitDiscMesh::UnitDiscMesh(MPI_Comm comm, std::size_t n,
std::size_t degree, std::size_t gdim)
: Mesh(comm)
{
dolfin_assert(n > 0);
dolfin_assert(gdim == 2 or gdim == 3);
dolfin_assert(degree == 1 or degree == 2);
MeshEditor editor;
editor.open(*this, 2, gdim, degree);
editor.init_vertices_global(1 + 3*n*(n + 1),
1 + 3*n*(n + 1));
std::size_t c = 0;
editor.add_vertex(c, Point(0,0,0));
++c;
for (std::size_t i = 1; i <= n; ++i)
for (std::size_t j = 0; j < 6*i; ++j)
{
double r = (double)i/(double)n;
double th = 2*M_PI*(double)j/(double)(6*i);
double x = r*cos(th);
double y = r*sin(th);
editor.add_vertex(c, Point(x, y, 0));
++c;
}
editor.init_cells(6*n*n);
c = 0;
std::size_t base_i = 0;
std::size_t row_i = 1;
for (std::size_t i = 1; i <= n; ++i)
{
std::size_t base_m = base_i;
base_i = 1 + 3*i*(i - 1);
std::size_t row_m = row_i;
row_i = 6*i;
for (std::size_t k = 0; k != 6; ++k)
for (std::size_t j = 0; j < (i*2 - 1); ++j)
{
std::size_t i0, i1, i2;
if (j%2 == 0)
{
i0 = base_i + (k*i + j/2)%row_i;
i1 = base_i + (k*i + j/2 + 1)%row_i;
i2 = base_m + (k*(i-1) + j/2)%row_m;
}
else
{
i0 = base_m + (k*(i-1) + j/2)%row_m;
i1 = base_m + (k*(i-1) + j/2 + 1)%row_m;
i2 = base_i + (k*i + j/2 + 1)%row_i;
}
editor.add_cell(c, i0, i1, i2);
++c;
}
}
// Initialise entities required for this degree polynomial mesh
// and allocate space for the point coordinate data
if (degree == 2)
{
editor.init_entities();
for (EdgeIterator e(*this); !e.end(); ++e)
{
Point v0 = Vertex(*this, e->entities(0)[0]).point();
Point v1 = Vertex(*this, e->entities(0)[1]).point();
Point pt = e->midpoint();
if (std::abs(v0.norm() - 1.0) < 1e-6 and
std::abs(v1.norm() - 1.0) < 1e-6)
pt *= v0.norm()/pt.norm();
// Add Edge-based point
editor.add_entity_point(1, 0, e->index(), pt);
}
}
editor.close();
}