void TestReadMeshes(void) throw(Exception)
{
{
READER_2D reader("mesh/test/data/square_4_elements_gmsh.msh");
TetrahedralMesh<2,2> mesh;
mesh.ConstructFromMeshReader(reader);
TS_ASSERT_EQUALS(mesh.GetNumNodes(), 5u);
TS_ASSERT_EQUALS(mesh.GetNumElements(), 4u);
TS_ASSERT_EQUALS(mesh.GetNumBoundaryElements(), 4u);
}
{
READER_3D reader("mesh/test/data/simple_cube_gmsh.msh");
TetrahedralMesh<3,3> mesh;
mesh.ConstructFromMeshReader(reader);
TS_ASSERT_EQUALS(mesh.GetNumNodes(), 14u);
TS_ASSERT_EQUALS(mesh.GetNumElements(), 24u);
TS_ASSERT_EQUALS(mesh.GetNumBoundaryElements(), 24u);
}
{
READER_2D reader("mesh/test/data/quad_square_4_elements_gmsh.msh",2,2);
QuadraticMesh<2> mesh;
mesh.ConstructFromMeshReader(reader);
TS_ASSERT_EQUALS(mesh.GetNumNodes(), 13u);
TS_ASSERT_EQUALS(mesh.GetNumElements(), 4u);
TS_ASSERT_EQUALS(mesh.GetNumBoundaryElements(), 4u);
}
{
READER_3D reader("mesh/test/data/quad_cube_gmsh.msh",2,2);
QuadraticMesh<3> mesh;
mesh.ConstructFromMeshReader(reader);
TS_ASSERT_EQUALS(mesh.GetNumNodes(), 63u);
TS_ASSERT_EQUALS(mesh.GetNumElements(), 24u);
TS_ASSERT_EQUALS(mesh.GetNumBoundaryElements(), 24u);
}
}
void TestAssembler2d() throw (Exception)
{
QuadraticMesh<2> mesh;
TrianglesMeshReader<2,2> mesh_reader("mesh/test/data/canonical_triangle_quadratic", 2, 2, false);
mesh.ConstructFromMeshReader(mesh_reader);
ContinuumMechanicsProblemDefinition<2> problem_defn(mesh);
double t1 = 2.6854233;
double t2 = 3.2574578;
// for the boundary element on the y=0 surface, create a traction
std::vector<BoundaryElement<1,2>*> boundary_elems;
std::vector<c_vector<double,2> > tractions;
c_vector<double,2> traction;
traction(0) = t1;
traction(1) = t2;
for (TetrahedralMesh<2,2>::BoundaryElementIterator iter
= mesh.GetBoundaryElementIteratorBegin();
iter != mesh.GetBoundaryElementIteratorEnd();
++iter)
{
if (fabs((*iter)->CalculateCentroid()[1])<1e-4)
{
BoundaryElement<1,2>* p_element = *iter;
boundary_elems.push_back(p_element);
tractions.push_back(traction);
}
}
assert(boundary_elems.size()==1);
problem_defn.SetTractionBoundaryConditions(boundary_elems, tractions);
ContinuumMechanicsNeumannBcsAssembler<2> assembler(&mesh, &problem_defn);
TS_ASSERT_THROWS_THIS(assembler.AssembleVector(), "Vector to be assembled has not been set");
Vec bad_sized_vec = PetscTools::CreateVec(2);
assembler.SetVectorToAssemble(bad_sized_vec, true);
TS_ASSERT_THROWS_THIS(assembler.AssembleVector(), "Vector provided to be assembled has size 2, not expected size of 18 ((dim+1)*num_nodes)");
Vec vec = PetscTools::CreateVec(3*mesh.GetNumNodes());
assembler.SetVectorToAssemble(vec, true);
assembler.AssembleVector();
ReplicatableVector vec_repl(vec);
// Note: on a 1d boundary element, intgl phi_i dx = 1/6 for the bases on the vertices
// and intgl phi_i dx = 4/6 for the basis at the interior node. (Here the integrals
// are over the canonical 1d element, [0,1], which is also the physical element for this
// mesh.
// node 0 is on the surface, and is a vertex
TS_ASSERT_DELTA(vec_repl[0], t1/6.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[1], t2/6.0, 1e-8);
// node 1 is on the surface, and is a vertex
TS_ASSERT_DELTA(vec_repl[3], t1/6.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[4], t2/6.0, 1e-8);
// nodes 2, 3, 4 are not on the surface
for(unsigned i=2; i<5; i++)
{
TS_ASSERT_DELTA(vec_repl[3*i], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[3*i], 0.0, 1e-8);
}
// node 5 is on the surface, and is an interior node
TS_ASSERT_DELTA(vec_repl[15], 4*t1/6.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[16], 4*t2/6.0, 1e-8);
// the rest of the vector is the pressure block and should be zero.
TS_ASSERT_DELTA(vec_repl[2], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[5], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[8], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[11], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[14], 0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[17], 0.0, 1e-8);
PetscTools::Destroy(vec);
PetscTools::Destroy(bad_sized_vec);
}
/*
* Test that the matrix is calculated correctly on the cannonical triangle.
* Tests against the analytical solution calculated by hand.
*/
void TestAssembler() throw(Exception)
{
QuadraticMesh<2> mesh;
TrianglesMeshReader<2,2> mesh_reader("mesh/test/data/canonical_triangle_quadratic", 2, 2, false);
mesh.ConstructFromMeshReader(mesh_reader);
double mu = 2.0;
c_vector<double,2> body_force;
double g1 = 1.34254;
double g2 = 75.3422;
body_force(0) = g1;
body_force(1) = g2;
StokesFlowProblemDefinition<2> problem_defn(mesh);
problem_defn.SetViscosity(mu);
problem_defn.SetBodyForce(body_force);
StokesFlowAssembler<2> assembler(&mesh, &problem_defn);
// The tests below test the assembler against hand-calculated variables for
// an OLD weak form (corresponding to different boundary conditions), not the
// current Stokes weak form. This factor converts the assembler to use the old
// weak form. See documentation for this variable for more details.
assembler.mScaleFactor = 0.0;
Vec vec = PetscTools::CreateVec(18);
Mat mat;
PetscTools::SetupMat(mat, 18, 18, 18);
assembler.SetVectorToAssemble(vec, true);
assembler.SetMatrixToAssemble(mat, true);
assembler.Assemble();
PetscMatTools::Finalise(mat);
double A[6][6] = {
{ 1.0, 1.0/6.0, 1.0/6.0, 0.0, -2.0/3.0, -2.0/3.0},
{ 1.0/6.0, 1.0/2.0, 0.0, 0.0, 0.0, -2.0/3.0},
{ 1.0/6.0, 0.0, 1.0/2.0, 0.0, -2.0/3.0, 0.0},
{ 0.0, 0.0, 0.0, 8.0/3.0, -4.0/3.0, -4.0/3.0},
{ -2.0/3.0, 0.0, -2.0/3.0, -4.0/3.0, 8.0/3.0, 0.0},
{ -2.0/3.0, -2.0/3.0, 0.0, -4.0/3.0, 0.0, 8.0/3.0}
};
double Bx[6][3] = {
{ -1.0/6.0, 0.0, 0.0},
{ 0.0, 1.0/6.0, 0.0},
{ 0.0, 0.0, 0.0},
{ 1.0/6.0, 1.0/6.0, 1.0/3.0},
{ -1.0/6.0, -1.0/6.0, -1.0/3.0},
{ 1.0/6.0, -1.0/6.0, 0.0},
};
double By[6][3] = {
{ -1.0/6.0, 0.0, 0.0},
{ 0.0, 0.0, 0.0},
{ 0.0, 0.0, 1.0/6.0},
{ 1.0/6.0, 1.0/3.0, 1.0/6.0},
{ 1.0/6.0, 0.0, -1.0/6.0},
{ -1.0/6.0, -1.0/3.0, -1.0/6.0},
};
c_matrix<double,18,18> exact_A = zero_matrix<double>(18);
// The diagonal 6x6 blocks
for (unsigned i=0; i<6; i++)
{
for (unsigned j=0; j<6; j++)
{
exact_A(3*i, 3*j) = mu*A[i][j];
exact_A(3*i+1,3*j+1) = mu*A[i][j];
}
}
// The 6x3 Blocks
for (unsigned i=0; i<6; i++)
{
for (unsigned j=0; j<3; j++)
{
exact_A(3*i,3*j+2) = -Bx[i][j];
exact_A(3*i+1,3*j+2) = -By[i][j];
//- as -Div(U)=0
exact_A(3*j+2,3*i) = -Bx[i][j];
exact_A(3*j+2,3*i+1) = -By[i][j];
}
}
int lo, hi;
MatGetOwnershipRange(mat, &lo, &hi);
for (unsigned i=lo; i<(unsigned)hi; i++)
{
for (unsigned j=0; j<18; j++)
{
TS_ASSERT_DELTA(PetscMatTools::GetElement(mat,i,j), exact_A(i,j), 1e-9);
}
}
ReplicatableVector vec_repl(vec);
// The first 6 entries in the vector correspond to nodes 0, 1, 2, i.e. the vertices.
// For these nodes, it can be shown that the integral of the corresponding
// basis function is zero, i.e. \intgl_{canonical element} \phi_i dV = 0.0 for i=0,1,2, phi_i the
// i-th QUADRATIC basis.
for(unsigned i=0; i<3; i++)
{
TS_ASSERT_DELTA(vec_repl[3*i], g1*0.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[3*i+1], g2*0.0, 1e-8);
}
// The next 6 entries in the vector correspond to nodes 3, 4, 5, i.e. the internal edges.
// For these nodes, it can be shown that the integral of the corresponding
// basis function is 1/6, i.e. \intgl_{canonical element} \phi_i dV = 1/6 for i=3,4,5, phi_i the
// i-th QUADRATIC basis.
for(unsigned i=3; i<6; i++)
{
TS_ASSERT_DELTA(vec_repl[3*i], g1/6.0, 1e-8);
TS_ASSERT_DELTA(vec_repl[3*i+1], g2/6.0, 1e-8);
}
// The pressure-block of the RHS vector should be zero.
TS_ASSERT_DELTA(vec_repl[2], 0.0, 1e-9);
TS_ASSERT_DELTA(vec_repl[5], 0.0, 1e-9);
TS_ASSERT_DELTA(vec_repl[8], 0.0, 1e-9);
TS_ASSERT_DELTA(vec_repl[11], 0.0, 1e-9);
TS_ASSERT_DELTA(vec_repl[14], 0.0, 1e-9);
TS_ASSERT_DELTA(vec_repl[17], 0.0, 1e-9);
// Replace the body force with a functional body force (see MyBodyForce) above, and
// assemble the vector again. This bit isn't so much to test the vector, but
// to test the physical location being integrated at is interpolated correctly
// and passed into the force function - see asserts in MyBodyForce.
mesh.Translate(0.5, 0.8);
Vec vec2 = PetscTools::CreateVec(18);
assembler.SetVectorToAssemble(vec2, true);
problem_defn.SetBodyForce(MyBodyForce);
assembler.Assemble();
ReplicatableVector vec_repl2(vec2);
for(unsigned i=3; i<6; i++)
{
TS_ASSERT_DELTA(vec_repl2[3*i], 10.0/6.0, 1e-8);
TS_ASSERT_DELTA(vec_repl2[3*i+1], 20.0/6.0, 1e-8);
}
PetscTools::Destroy(vec);
PetscTools::Destroy(vec2);
PetscTools::Destroy(mat);
}