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mfem/examples/ex25.cpp
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// MFEM Example 25
//
// Compile with: make ex25
//
// Sample runs: ex25 -o 2 -f 1.0 -ref 2 -prob 0
// ex25 -o 3 -f 10.0 -ref 2 -prob 1
// ex25 -o 2 -f 5.0 -ref 4 -prob 2
// ex25 -o 2 -f 1.0 -ref 2 -prob 3
// ex25 -o 2 -f 1.0 -ref 2 -prob 0 -m ../data/beam-quad.mesh
// ex25 -o 2 -f 8.0 -ref 3 -prob 4 -m ../data/inline-quad.mesh
// ex25 -o 2 -f 2.0 -ref 1 -prob 4 -m ../data/inline-hex.mesh
//
// Device sample runs:
// ex25 -o 2 -f 8.0 -ref 3 -prob 4 -m ../data/inline-quad.mesh -pa -d cuda
// ex25 -o 2 -f 2.0 -ref 1 -prob 4 -m ../data/inline-hex.mesh -pa -d cuda
//
// Description: This example code solves a simple electromagnetic wave
// propagation problem corresponding to the second order
// indefinite Maxwell equation
//
// (1/mu) * curl curl E - \omega^2 * epsilon E = f
//
// with a Perfectly Matched Layer (PML).
//
// The example demonstrates discretization with Nedelec finite
// elements in 2D or 3D, as well as the use of complex-valued
// bilinear and linear forms. Several test problems are included,
// with prob = 0-3 having known exact solutions, see "On perfectly
// matched layers for discontinuous Petrov-Galerkin methods" by
// Vaziri Astaneh, Keith, Demkowicz, Comput Mech 63, 2019.
//
// We recommend viewing Example 22 before viewing this example.
#include "mfem.hpp"
#include <memory>
#include <fstream>
#include <iostream>
#ifdef _WIN32
#define jn(n, x) _jn(n, x)
#define yn(n, x) _yn(n, x)
#endif
using namespace std;
using namespace mfem;
// Class for setting up a simple Cartesian PML region
class PML
{
private:
Mesh *mesh;
int dim;
// Length of the PML Region in each direction
Array2D<real_t> length;
// Computational Domain Boundary
Array2D<real_t> comp_dom_bdr;
// Domain Boundary
Array2D<real_t> dom_bdr;
// Integer Array identifying elements in the PML
// 0: in the PML, 1: not in the PML
Array<int> elems;
// Compute Domain and Computational Domain Boundaries
void SetBoundaries();
public:
// Constructor
PML(Mesh *mesh_,Array2D<real_t> length_);
// Return Computational Domain Boundary
Array2D<real_t> GetCompDomainBdr() {return comp_dom_bdr;}
// Return Domain Boundary
Array2D<real_t> GetDomainBdr() {return dom_bdr;}
// Return Markers list for elements
Array<int> * GetMarkedPMLElements() {return &elems;}
// Mark elements in the PML region
void SetAttributes(Mesh *mesh_);
// PML complex stretching function
void StretchFunction(const Vector &x, vector<complex<real_t>> &dxs);
};
// Class for returning the PML coefficients of the bilinear form
class PMLDiagMatrixCoefficient : public VectorCoefficient
{
private:
PML * pml = nullptr;
void (*Function)(const Vector &, PML *, Vector &);
public:
PMLDiagMatrixCoefficient(int dim, void(*F)(const Vector &, PML *,
Vector &),
PML * pml_)
: VectorCoefficient(dim), pml(pml_), Function(F)
{}
using VectorCoefficient::Eval;
void Eval(Vector &K, ElementTransformation &T,
const IntegrationPoint &ip) override
{
real_t x[3];
Vector transip(x, 3);
T.Transform(ip, transip);
K.SetSize(vdim);
(*Function)(transip, pml, K);
}
};
void maxwell_solution(const Vector &x, vector<complex<real_t>> &Eval);
void E_bdr_data_Re(const Vector &x, Vector &E);
void E_bdr_data_Im(const Vector &x, Vector &E);
void E_exact_Re(const Vector &x, Vector &E);
void E_exact_Im(const Vector &x, Vector &E);
void source(const Vector &x, Vector & f);
// Functions for computing the necessary coefficients after PML stretching.
// J is the Jacobian matrix of the stretching function
void detJ_JT_J_inv_Re(const Vector &x, PML * pml, Vector &D);
void detJ_JT_J_inv_Im(const Vector &x, PML * pml, Vector &D);
void detJ_JT_J_inv_abs(const Vector &x, PML * pml, Vector &D);
void detJ_inv_JT_J_Re(const Vector &x, PML * pml, Vector &D);
void detJ_inv_JT_J_Im(const Vector &x, PML * pml, Vector &D);
void detJ_inv_JT_J_abs(const Vector &x, PML * pml, Vector &D);
Array2D<real_t> comp_domain_bdr;
Array2D<real_t> domain_bdr;
real_t mu = 1.0;
real_t epsilon = 1.0;
real_t omega;
int dim;
bool exact_known = false;
template <typename T> T pow2(const T &x) { return x*x; }
enum prob_type
{
beam, // Wave propagating in a beam-like domain
disc, // Point source propagating in the square-disc domain
lshape, // Point source propagating in the L-shape domain
fichera, // Point source propagating in the fichera domain
load_src // Approximated point source with PML all around
};
prob_type prob;
int main(int argc, char *argv[])
{
// 1. Parse command-line options.
const char *mesh_file = nullptr;
int order = 1;
int ref_levels = 3;
int iprob = 4;
real_t freq = 5.0;
bool herm_conv = true;
bool umf_solver = false;
bool visualization = 1;
bool pa = false;
const char *device_config = "cpu";
OptionsParser args(argc, argv);
args.AddOption(&mesh_file, "-m", "--mesh",
"Mesh file to use.");
args.AddOption(&order, "-o", "--order",
"Finite element order (polynomial degree).");
args.AddOption(&iprob, "-prob", "--problem", "Problem case"
" 0: beam, 1: disc, 2: lshape, 3: fichera, 4: General");
args.AddOption(&ref_levels, "-ref", "--refinements",
"Number of refinements");
args.AddOption(&mu, "-mu", "--permeability",
"Permeability of free space (or 1/(spring constant)).");
args.AddOption(&epsilon, "-eps", "--permittivity",
"Permittivity of free space (or mass constant).");
args.AddOption(&freq, "-f", "--frequency",
"Frequency (in Hz).");
args.AddOption(&herm_conv, "-herm", "--hermitian", "-no-herm",
"--no-hermitian", "Use convention for Hermitian operators.");
#ifdef MFEM_USE_SUITESPARSE
args.AddOption(&umf_solver, "-umf", "--umfpack", "-no-umf",
"--no-umfpack", "Use the UMFPack Solver.");
#endif
args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
"--no-visualization",
"Enable or disable GLVis visualization.");
args.AddOption(&pa, "-pa", "--partial-assembly", "-no-pa",
"--no-partial-assembly", "Enable Partial Assembly.");
args.AddOption(&device_config, "-d", "--device",
"Device configuration string, see Device::Configure().");
args.Parse();
if (iprob > 4) { iprob = 4; }
prob = (prob_type)iprob;
// 2. Enable hardware devices such as GPUs, and programming models such as
// CUDA, OCCA, RAJA and OpenMP based on command line options.
Device device(device_config);
device.Print();
// 3. Setup the mesh
if (!mesh_file)
{
exact_known = true;
switch (prob)
{
case beam:
mesh_file = "../data/beam-hex.mesh";
break;
case disc:
mesh_file = "../data/square-disc.mesh";
break;
case lshape:
mesh_file = "../data/l-shape.mesh";
break;
case fichera:
mesh_file = "../data/fichera.mesh";
break;
default:
exact_known = false;
mesh_file = "../data/inline-quad.mesh";
break;
}
}
if (!args.Good())
{
args.PrintUsage(cout);
return 1;
}
args.PrintOptions(cout);
Mesh * mesh = new Mesh(mesh_file, 1, 1);
dim = mesh->Dimension();
// Angular frequency
omega = real_t(2.0 * M_PI) * freq;
// Setup PML length
Array2D<real_t> length(dim, 2); length = 0.0;
// 4. Setup the Cartesian PML region.
switch (prob)
{
case disc:
length = 0.2;
break;
case lshape:
length(0, 0) = 0.1;
length(1, 0) = 0.1;
break;
case fichera:
length(0, 1) = 0.5;
length(1, 1) = 0.5;
length(2, 1) = 0.5;
break;
case beam:
length(0, 1) = 2.0;
break;
default:
length = 0.25;
break;
}
PML * pml = new PML(mesh,length);
comp_domain_bdr = pml->GetCompDomainBdr();
domain_bdr = pml->GetDomainBdr();
// 5. Refine the mesh to increase the resolution.
for (int l = 0; l < ref_levels; l++)
{
mesh->UniformRefinement();
}
// 6. Set element attributes in order to distinguish elements in the
// PML region
pml->SetAttributes(mesh);
// 7. Define a finite element space on the mesh. Here we use the Nedelec
// finite elements of the specified order.
FiniteElementCollection *fec = new ND_FECollection(order, dim);
FiniteElementSpace *fespace = new FiniteElementSpace(mesh, fec);
int size = fespace->GetTrueVSize();
cout << "Number of finite element unknowns: " << size << endl;
// 8. Determine the list of true essential boundary dofs. In this example,
// the boundary conditions are defined based on the specific mesh and the
// problem type.
Array<int> ess_tdof_list;
Array<int> ess_bdr;
if (mesh->bdr_attributes.Size())
{
ess_bdr.SetSize(mesh->bdr_attributes.Max());
ess_bdr = 1;
if (prob == lshape || prob == fichera)
{
ess_bdr = 0;
for (int j = 0; j < mesh->GetNBE(); j++)
{
Vector center(dim);
int bdrgeom = mesh->GetBdrElementGeometry(j);
ElementTransformation * tr = mesh->GetBdrElementTransformation(j);
tr->Transform(Geometries.GetCenter(bdrgeom),center);
int k = mesh->GetBdrAttribute(j);
switch (prob)
{
case lshape:
if (center[0] == 1_r || center[0] == 0.5_r ||
center[1] == 0.5_r)
{
ess_bdr[k - 1] = 1;
}
break;
case fichera:
if (center[0] == -1_r || center[0] == 0_r ||
center[1] == 0_r || center[2] == 0_r)
{
ess_bdr[k - 1] = 1;
}
break;
default:
break;
}
}
}
}
fespace->GetEssentialTrueDofs(ess_bdr, ess_tdof_list);
// 9. Setup Complex Operator convention
ComplexOperator::Convention conv =
herm_conv ? ComplexOperator::HERMITIAN : ComplexOperator::BLOCK_SYMMETRIC;
// 10. Set up the linear form b(.) which corresponds to the right-hand side of
// the FEM linear system.
VectorFunctionCoefficient f(dim, source);
ComplexLinearForm b(fespace, conv);
if (prob == load_src)
{
b.AddDomainIntegrator(NULL, new VectorFEDomainLFIntegrator(f));
}
b = 0.0;
b.Assemble();
// 11. Define the solution vector x as a complex finite element grid function
// corresponding to fespace.
ComplexGridFunction x(fespace);
x = 0.0;
VectorFunctionCoefficient E_Re(dim, E_bdr_data_Re);
VectorFunctionCoefficient E_Im(dim, E_bdr_data_Im);
x.ProjectBdrCoefficientTangent(E_Re, E_Im, ess_bdr);
// 12. Set up the sesquilinear form a(.,.)
//
// In Comp
// Domain: 1/mu (Curl E, Curl F) - omega^2 * epsilon (E,F)
//
// In PML: 1/mu (1/det(J) J^T J Curl E, Curl F)
// - omega^2 * epsilon (det(J) * (J^T J)^-1 * E, F)
//
// where J denotes the Jacobian Matrix of the PML Stretching function
Array<int> attr;
Array<int> attrPML;
if (mesh->attributes.Size())
{
attr.SetSize(mesh->attributes.Max());
attrPML.SetSize(mesh->attributes.Max());
attr = 0; attr[0] = 1;
attrPML = 0;
if (mesh->attributes.Max() > 1)
{
attrPML[1] = 1;
}
}
ConstantCoefficient muinv(1_r / mu);
ConstantCoefficient omeg(-pow2(omega) * epsilon);
RestrictedCoefficient restr_muinv(muinv,attr);
RestrictedCoefficient restr_omeg(omeg,attr);
// Integrators inside the computational domain (excluding the PML region)
SesquilinearForm a(fespace, conv);
a.AddDomainIntegrator(new CurlCurlIntegrator(restr_muinv),NULL);
a.AddDomainIntegrator(new VectorFEMassIntegrator(restr_omeg),NULL);
int cdim = (dim == 2) ? 1 : dim;
PMLDiagMatrixCoefficient pml_c1_Re(cdim,detJ_inv_JT_J_Re, pml);
PMLDiagMatrixCoefficient pml_c1_Im(cdim,detJ_inv_JT_J_Im, pml);
ScalarVectorProductCoefficient c1_Re(muinv,pml_c1_Re);
ScalarVectorProductCoefficient c1_Im(muinv,pml_c1_Im);
VectorRestrictedCoefficient restr_c1_Re(c1_Re,attrPML);
VectorRestrictedCoefficient restr_c1_Im(c1_Im,attrPML);
PMLDiagMatrixCoefficient pml_c2_Re(dim, detJ_JT_J_inv_Re,pml);
PMLDiagMatrixCoefficient pml_c2_Im(dim, detJ_JT_J_inv_Im,pml);
ScalarVectorProductCoefficient c2_Re(omeg,pml_c2_Re);
ScalarVectorProductCoefficient c2_Im(omeg,pml_c2_Im);
VectorRestrictedCoefficient restr_c2_Re(c2_Re,attrPML);
VectorRestrictedCoefficient restr_c2_Im(c2_Im,attrPML);
// Integrators inside the PML region
a.AddDomainIntegrator(new CurlCurlIntegrator(restr_c1_Re),
new CurlCurlIntegrator(restr_c1_Im));
a.AddDomainIntegrator(new VectorFEMassIntegrator(restr_c2_Re),
new VectorFEMassIntegrator(restr_c2_Im));
// 13. Assemble the bilinear form and the corresponding linear system,
// applying any necessary transformations such as: assembly, eliminating
// boundary conditions, applying conforming constraints for
// non-conforming AMR, etc.
if (pa) { a.SetAssemblyLevel(AssemblyLevel::PARTIAL); }
a.Assemble(0);
OperatorPtr A;
Vector B, X;
a.FormLinearSystem(ess_tdof_list, x, b, A, X, B);
// 14. Solve using a direct or an iterative solver
#ifdef MFEM_USE_SUITESPARSE
if (!pa && umf_solver)
{
ComplexUMFPackSolver csolver(*A.As<ComplexSparseMatrix>());
csolver.Control[UMFPACK_ORDERING] = UMFPACK_ORDERING_METIS;
csolver.SetPrintLevel(1);
csolver.Mult(B, X);
}
#endif
// 14a. Set up the Bilinear form a(.,.) for the preconditioner
//
// In Comp
// Domain: 1/mu (Curl E, Curl F) + omega^2 * epsilon (E,F)
//
// In PML: 1/mu (abs(1/det(J) J^T J) Curl E, Curl F)
// + omega^2 * epsilon (abs(det(J) * (J^T J)^-1) * E, F)
if (pa || !umf_solver)
{
ConstantCoefficient absomeg(pow2(omega) * epsilon);
RestrictedCoefficient restr_absomeg(absomeg,attr);
BilinearForm prec(fespace);
prec.AddDomainIntegrator(new CurlCurlIntegrator(restr_muinv));
prec.AddDomainIntegrator(new VectorFEMassIntegrator(restr_absomeg));
PMLDiagMatrixCoefficient pml_c1_abs(cdim,detJ_inv_JT_J_abs, pml);
ScalarVectorProductCoefficient c1_abs(muinv,pml_c1_abs);
VectorRestrictedCoefficient restr_c1_abs(c1_abs,attrPML);
PMLDiagMatrixCoefficient pml_c2_abs(dim, detJ_JT_J_inv_abs,pml);
ScalarVectorProductCoefficient c2_abs(absomeg,pml_c2_abs);
VectorRestrictedCoefficient restr_c2_abs(c2_abs,attrPML);
prec.AddDomainIntegrator(new CurlCurlIntegrator(restr_c1_abs));
prec.AddDomainIntegrator(new VectorFEMassIntegrator(restr_c2_abs));
if (pa) { prec.SetAssemblyLevel(AssemblyLevel::PARTIAL); }
prec.Assemble();
// 14b. Define and apply a GMRES solver for AU=B with a block diagonal
// preconditioner based on the Gauss-Seidel or Jacobi sparse smoother.
Array<int> offsets(3);
offsets[0] = 0;
offsets[1] = fespace->GetTrueVSize();
offsets[2] = fespace->GetTrueVSize();
offsets.PartialSum();
std::unique_ptr<Operator> pc_r;
std::unique_ptr<Operator> pc_i;
real_t s = (conv == ComplexOperator::HERMITIAN) ? -1_r : 1_r;
if (pa)
{
// Jacobi Smoother
pc_r.reset(new OperatorJacobiSmoother(prec, ess_tdof_list));
pc_i.reset(new ScaledOperator(pc_r.get(), s));
}
else
{
OperatorPtr PCOpAh;
prec.SetDiagonalPolicy(mfem::Operator::DIAG_ONE);
prec.FormSystemMatrix(ess_tdof_list, PCOpAh);
// Gauss-Seidel Smoother
pc_r.reset(new GSSmoother(*PCOpAh.As<SparseMatrix>()));
pc_i.reset(new ScaledOperator(pc_r.get(), s));
}
BlockDiagonalPreconditioner BlockDP(offsets);
BlockDP.SetDiagonalBlock(0, pc_r.get());
BlockDP.SetDiagonalBlock(1, pc_i.get());
GMRESSolver gmres;
gmres.SetPrintLevel(1);
gmres.SetKDim(200);
gmres.SetMaxIter(pa ? 5000 : 2000);
gmres.SetRelTol(1e-5);
gmres.SetAbsTol(0.0);
gmres.SetOperator(*A);
gmres.SetPreconditioner(BlockDP);
gmres.Mult(B, X);
}
// 15. Recover the solution as a finite element grid function and compute the
// errors if the exact solution is known.
a.RecoverFEMSolution(X, b, x);
// If exact is known compute the error
if (exact_known)
{
VectorFunctionCoefficient E_ex_Re(dim, E_exact_Re);
VectorFunctionCoefficient E_ex_Im(dim, E_exact_Im);
int order_quad = max(2, 2 * order + 1);
const IntegrationRule *irs[Geometry::NumGeom];
for (int i = 0; i < Geometry::NumGeom; ++i)
{
irs[i] = &(IntRules.Get(i, order_quad));
}
real_t L2Error_Re = x.real().ComputeL2Error(E_ex_Re, irs,
pml->GetMarkedPMLElements());
real_t L2Error_Im = x.imag().ComputeL2Error(E_ex_Im, irs,
pml->GetMarkedPMLElements());
ComplexGridFunction x_gf0(fespace);
x_gf0 = 0.0;
real_t norm_E_Re, norm_E_Im;
norm_E_Re = x_gf0.real().ComputeL2Error(E_ex_Re, irs,
pml->GetMarkedPMLElements());
norm_E_Im = x_gf0.imag().ComputeL2Error(E_ex_Im, irs,
pml->GetMarkedPMLElements());
cout << "\n Relative Error (Re part): || E_h - E || / ||E|| = "
<< L2Error_Re / norm_E_Re
<< "\n Relative Error (Im part): || E_h - E || / ||E|| = "
<< L2Error_Im / norm_E_Im
<< "\n Total Error: "
<< sqrt(L2Error_Re*L2Error_Re + L2Error_Im*L2Error_Im) << "\n\n";
}
// 16. Save the refined mesh and the solution. This output can be viewed
// later using GLVis: "glvis -m mesh -g sol".
{
ofstream mesh_ofs("ex25.mesh");
mesh_ofs.precision(8);
mesh->Print(mesh_ofs);
ofstream sol_r_ofs("ex25-sol_r.gf");
ofstream sol_i_ofs("ex25-sol_i.gf");
sol_r_ofs.precision(8);
sol_i_ofs.precision(8);
x.real().Save(sol_r_ofs);
x.imag().Save(sol_i_ofs);
}
// 17. Send the solution by socket to a GLVis server.
if (visualization)
{
// Define visualization keys for GLVis (see GLVis documentation)
string keys;
keys = (dim == 3) ? "keys macF\n" : keys = "keys amrRljcUUuu\n";
if (prob == beam && dim == 3) {keys = "keys macFFiYYYYYYYYYYYYYYYYYY\n";}
if (prob == beam && dim == 2) {keys = "keys amrRljcUUuuu\n"; }
char vishost[] = "localhost";
int visport = 19916;
socketstream sol_sock_re(vishost, visport);
sol_sock_re.precision(8);
sol_sock_re << "solution\n"
<< *mesh << x.real() << keys
<< "window_title 'Solution real part'" << flush;
socketstream sol_sock_im(vishost, visport);
sol_sock_im.precision(8);
sol_sock_im << "solution\n"
<< *mesh << x.imag() << keys
<< "window_title 'Solution imag part'" << flush;
GridFunction x_t(fespace);
x_t = x.real();
socketstream sol_sock(vishost, visport);
sol_sock.precision(8);
sol_sock << "solution\n"
<< *mesh << x_t << keys << "autoscale off\n"
<< "window_title 'Harmonic Solution (t = 0.0 T)'"
<< "pause\n" << flush;
cout << "GLVis visualization paused."
<< " Press space (in the GLVis window) to resume it.\n";
int num_frames = 32;
int i = 0;
while (sol_sock)
{
real_t t = (real_t)(i % num_frames) / num_frames;
ostringstream oss;
oss << "Harmonic Solution (t = " << t << " T)";
add(cos(real_t(2.0 * M_PI) * t), x.real(),
sin(real_t(2.0 * M_PI) * t), x.imag(), x_t);
sol_sock << "solution\n"
<< *mesh << x_t
<< "window_title '" << oss.str() << "'" << flush;
i++;
}
}
// 18. Free the used memory.
delete pml;
delete fespace;
delete fec;
delete mesh;
return 0;
}
void source(const Vector &x, Vector &f)
{
Vector center(dim);
real_t r = 0.0;
for (int i = 0; i < dim; ++i)
{
center(i) = 0.5_r * (comp_domain_bdr(i, 0) + comp_domain_bdr(i, 1));
r += pow2(x[i] - center[i]);
}
real_t n = 5_r * omega * sqrt(epsilon * mu) / real_t(M_PI);
real_t coeff = pow2(n) / real_t(M_PI);
real_t alpha = -pow2(n) * r;
f = 0.0;
f[0] = coeff * exp(alpha);
}
void maxwell_solution(const Vector &x, vector<complex<real_t>> &E)
{
// Initialize
for (int i = 0; i < dim; ++i)
{
E[i] = 0.0;
}
constexpr complex<real_t> zi = complex<real_t>(0., 1.);
real_t k = omega * sqrt(epsilon * mu);
switch (prob)
{
case disc:
case lshape:
case fichera:
{
Vector shift(dim);
shift = 0.0;
if (prob == fichera) { shift = 1.0; }
if (prob == disc) { shift = -0.5; }
if (prob == lshape) { shift = -1.0; }
if (dim == 2)
{
real_t x0 = x(0) + shift(0);
real_t x1 = x(1) + shift(1);
real_t r = sqrt(x0 * x0 + x1 * x1);
real_t beta = k * r;
// Bessel functions
complex<real_t> Ho, Ho_r, Ho_rr;
Ho = real_t(jn(0, beta)) + zi * real_t(yn(0, beta));
Ho_r = -k * (real_t(jn(1, beta)) + zi * real_t(yn(1, beta)));
Ho_rr = -k * k * (1_r / beta *
(real_t(jn(1, beta)) + zi * real_t(yn(1, beta))) -
(real_t(jn(2, beta)) + zi * real_t(yn(2, beta))));
// First derivatives
real_t r_x = x0 / r;
real_t r_y = x1 / r;
real_t r_xy = -(r_x / r) * r_y;
real_t r_xx = (1_r / r) * (1_r - r_x * r_x);
complex<real_t> val, val_xx, val_xy;
val = real_t(0.25) * zi * Ho;
val_xx = real_t(0.25) * zi * (r_xx * Ho_r + r_x * r_x * Ho_rr);
val_xy = real_t(0.25) * zi * (r_xy * Ho_r + r_x * r_y * Ho_rr);
E[0] = zi / k * (k * k * val + val_xx);
E[1] = zi / k * val_xy;
}
else if (dim == 3)
{
real_t x0 = x(0) + shift(0);
real_t x1 = x(1) + shift(1);
real_t x2 = x(2) + shift(2);
real_t r = sqrt(x0 * x0 + x1 * x1 + x2 * x2);
real_t r_x = x0 / r;
real_t r_y = x1 / r;
real_t r_z = x2 / r;
real_t r_xx = (1_r / r) * (1_r - r_x * r_x);
real_t r_yx = -(r_y / r) * r_x;
real_t r_zx = -(r_z / r) * r_x;
complex<real_t> val, val_r, val_rr;
val = exp(zi * k * r) / r;
val_r = val / r * (zi * k * r - 1_r);
val_rr = val / (r * r) * (-k * k * r * r
- real_t(2) * zi * k * r + real_t(2));
complex<real_t> val_xx, val_yx, val_zx;
val_xx = val_rr * r_x * r_x + val_r * r_xx;
val_yx = val_rr * r_x * r_y + val_r * r_yx;
val_zx = val_rr * r_x * r_z + val_r * r_zx;
complex<real_t> alpha = zi * k / real_t(4) / (real_t) M_PI / k / k;
E[0] = alpha * (k * k * val + val_xx);
E[1] = alpha * val_yx;
E[2] = alpha * val_zx;
}
break;
}
case beam:
{
// T_10 mode
if (dim == 3)
{
real_t k10 = sqrt(k * k - real_t(M_PI * M_PI));
E[1] = -zi * k / (real_t) M_PI *
sin((real_t) M_PI*x(2))*exp(zi * k10 * x(0));
}
else if (dim == 2)
{
E[1] = -zi * k / (real_t) M_PI * exp(zi * k * x(0));
}
break;
}
default:
break;
}
}
void E_exact_Re(const Vector &x, Vector &E)
{
vector<complex<real_t>> Eval(E.Size());
maxwell_solution(x, Eval);
for (int i = 0; i < dim; ++i)
{
E[i] = Eval[i].real();
}
}
void E_exact_Im(const Vector &x, Vector &E)
{
vector<complex<real_t>> Eval(E.Size());
maxwell_solution(x, Eval);
for (int i = 0; i < dim; ++i)
{
E[i] = Eval[i].imag();
}
}
void E_bdr_data_Re(const Vector &x, Vector &E)
{
E = 0.0;
bool in_pml = false;
for (int i = 0; i < dim; ++i)
{
// check if in PML
if (x(i) - comp_domain_bdr(i, 0) < 0_r ||
x(i) - comp_domain_bdr(i, 1) > 0_r)
{
in_pml = true;
break;
}
}
if (!in_pml)
{
vector<complex<real_t>> Eval(E.Size());
maxwell_solution(x, Eval);
for (int i = 0; i < dim; ++i)
{
E[i] = Eval[i].real();
}
}
}
// Define bdr_data solution
void E_bdr_data_Im(const Vector &x, Vector &E)
{
E = 0.0;
bool in_pml = false;
for (int i = 0; i < dim; ++i)
{
// check if in PML
if (x(i) - comp_domain_bdr(i, 0) < 0_r ||
x(i) - comp_domain_bdr(i, 1) > 0_r)
{
in_pml = true;
break;
}
}
if (!in_pml)
{
vector<complex<real_t>> Eval(E.Size());
maxwell_solution(x, Eval);
for (int i = 0; i < dim; ++i)
{
E[i] = Eval[i].imag();
}
}
}
void detJ_JT_J_inv_Re(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det(1.0, 0.0);
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
for (int i = 0; i < dim; ++i)
{
D(i) = (det / pow2(dxs[i])).real();
}
}
void detJ_JT_J_inv_Im(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det = 1.0;
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
for (int i = 0; i < dim; ++i)
{
D(i) = (det / pow2(dxs[i])).imag();
}
}
void detJ_JT_J_inv_abs(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det = 1.0;
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
for (int i = 0; i < dim; ++i)
{
D(i) = abs(det / pow2(dxs[i]));
}
}
void detJ_inv_JT_J_Re(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det(1.0, 0.0);
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
// in the 2D case the coefficient is scalar 1/det(J)
if (dim == 2)
{
D = (1_r / det).real();
}
else
{
for (int i = 0; i < dim; ++i)
{
D(i) = (pow2(dxs[i]) / det).real();
}
}
}
void detJ_inv_JT_J_Im(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det = 1.0;
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
if (dim == 2)
{
D = (1_r / det).imag();
}
else
{
for (int i = 0; i < dim; ++i)
{
D(i) = (pow2(dxs[i]) / det).imag();
}
}
}
void detJ_inv_JT_J_abs(const Vector &x, PML * pml, Vector &D)
{
vector<complex<real_t>> dxs(dim);
complex<real_t> det = 1.0;
pml->StretchFunction(x, dxs);
for (int i = 0; i < dim; ++i)
{
det *= dxs[i];
}
if (dim == 2)
{
D = abs(1_r / det);
}
else
{
for (int i = 0; i < dim; ++i)
{
D(i) = abs(pow2(dxs[i]) / det);
}
}
}
PML::PML(Mesh *mesh_, Array2D<real_t> length_)
: mesh(mesh_), length(length_)
{
dim = mesh->Dimension();
SetBoundaries();
}
void PML::SetBoundaries()
{
comp_dom_bdr.SetSize(dim, 2);
dom_bdr.SetSize(dim, 2);
Vector pmin, pmax;
mesh->GetBoundingBox(pmin, pmax);
for (int i = 0; i < dim; i++)
{
dom_bdr(i, 0) = pmin(i);
dom_bdr(i, 1) = pmax(i);
comp_dom_bdr(i, 0) = dom_bdr(i, 0) + length(i, 0);
comp_dom_bdr(i, 1) = dom_bdr(i, 1) - length(i, 1);
}
}
void PML::SetAttributes(Mesh *mesh_)
{
// Initialize bdr attributes
for (int i = 0; i < mesh_->GetNBE(); ++i)
{
mesh_->GetBdrElement(i)->SetAttribute(i+1);
}
int nrelem = mesh_->GetNE();
elems.SetSize(nrelem);
// Loop through the elements and identify which of them are in the PML
for (int i = 0; i < nrelem; ++i)
{
elems[i] = 1;
bool in_pml = false;
Element *el = mesh_->GetElement(i);
Array<int> vertices;
// Initialize attribute
el->SetAttribute(1);
el->GetVertices(vertices);
int nrvert = vertices.Size();
// Check if any vertex is in the PML
for (int iv = 0; iv < nrvert; ++iv)
{
int vert_idx = vertices[iv];
real_t *coords = mesh_->GetVertex(vert_idx);
for (int comp = 0; comp < dim; ++comp)
{
if (coords[comp] > comp_dom_bdr(comp, 1) ||
coords[comp] < comp_dom_bdr(comp, 0))
{
in_pml = true;
break;
}
}
}
if (in_pml)
{
elems[i] = 0;
el->SetAttribute(2);
}
}
mesh_->SetAttributes();
}
void PML::StretchFunction(const Vector &x,
vector<complex<real_t>> &dxs)
{
constexpr complex<real_t> zi = complex<real_t>(0., 1.);
real_t n = 2.0;
real_t c = 5.0;
real_t coeff;
real_t k = omega * sqrt(epsilon * mu);
// Stretch in each direction independently
for (int i = 0; i < dim; ++i)
{
dxs[i] = 1.0;
if (x(i) >= comp_domain_bdr(i, 1))
{
coeff = n * c / k / pow(length(i, 1), n);
dxs[i] = 1_r + zi * coeff *
abs(pow(x(i) - comp_domain_bdr(i, 1), n - 1_r));
}
if (x(i) <= comp_domain_bdr(i, 0))
{
coeff = n * c / k / pow(length(i, 0), n);
dxs[i] = 1_r + zi * coeff *
abs(pow(x(i) - comp_domain_bdr(i, 0), n - 1_r));
}
}
}