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mfem/examples/ex31p.cpp
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2023-12-13 12:51:43 -08:00

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// MFEM Example 31 - Parallel Version
//
// Compile with: make ex31p
//
// Sample runs: mpirun -np 4 ex31p -m ../data/hexagon.mesh -o 2
// mpirun -np 4 ex31p -m ../data/star.mesh
// mpirun -np 4 ex31p -m ../data/square-disc.mesh -o 2
// mpirun -np 4 ex31p -m ../data/fichera.mesh -o 3 -rs 1 -rp 0
// mpirun -np 4 ex31p -m ../data/square-disc-nurbs.mesh -o 3
// mpirun -np 4 ex31p -m ../data/amr-quad.mesh -o 2 -rs 1
// mpirun -np 4 ex31p -m ../data/amr-hex.mesh -rs 1
//
// Description: This example code solves a simple electromagnetic diffusion
// problem corresponding to the second order definite Maxwell
// equation curl curl E + sigma E = f with boundary condition
// E x n = <given tangential field>. In this example sigma is an
// anisotropic 3x3 tensor. Here, we use a given exact solution E
// and compute the corresponding r.h.s. f. We discretize with
// Nedelec finite elements in 1D, 2D, or 3D.
//
// The example demonstrates the use of restricted H(curl) finite
// element spaces with the curl-curl and the (vector finite
// element) mass bilinear form, as well as the computation of
// discretization error when the exact solution is known. These
// restricted spaces allow the solution of 1D or 2D
// electromagnetic problems which involve 3D field vectors. Such
// problems arise in plasma physics and crystallography.
//
// We recommend viewing example 3 before viewing this example.
#include "mfem.hpp"
#include <fstream>
#include <iostream>
using namespace std;
using namespace mfem;
// Exact solution, E, and r.h.s., f. See below for implementation.
void E_exact(const Vector &, Vector &);
void CurlE_exact(const Vector &, Vector &);
void f_exact(const Vector &, Vector &);
real_t freq = 1.0, kappa;
int dim;
int main(int argc, char *argv[])
{
// 1. Initialize MPI.
Mpi::Init(argc, argv);
int num_procs = Mpi::WorldSize();
int myid = Mpi::WorldRank();
Hypre::Init();
// 2. Parse command-line options.
const char *mesh_file = "../data/inline-quad.mesh";
int ser_ref_levels = 2;
int par_ref_levels = 1;
int order = 1;
bool use_ams = true;
bool visualization = 1;
OptionsParser args(argc, argv);
args.AddOption(&mesh_file, "-m", "--mesh",
"Mesh file to use.");
args.AddOption(&ser_ref_levels, "-rs", "--refine-serial",
"Number of times to refine the mesh uniformly in serial.");
args.AddOption(&par_ref_levels, "-rp", "--refine-parallel",
"Number of times to refine the mesh uniformly in parallel.");
args.AddOption(&order, "-o", "--order",
"Finite element order (polynomial degree).");
args.AddOption(&freq, "-f", "--frequency", "Set the frequency for the exact"
" solution.");
args.AddOption(&use_ams, "-ams", "--hypre-ams", "-slu",
"--superlu", "Use AMS or SuperLU solver.");
args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
"--no-visualization",
"Enable or disable GLVis visualization.");
args.ParseCheck();
kappa = freq * M_PI;
// 3. Read the (serial) mesh from the given mesh file on all processors. We
// can handle triangular, quadrilateral, tetrahedral, hexahedral, surface
// and volume meshes with the same code.
Mesh *mesh = new Mesh(mesh_file, 1, 1);
dim = mesh->Dimension();
// 4. Refine the serial mesh on all processors to increase the resolution. In
// this example we do 'ref_levels' of uniform refinement (2 by default, or
// specified on the command line with -rs).
for (int lev = 0; lev < ser_ref_levels; lev++)
{
mesh->UniformRefinement();
}
// 5. Define a parallel mesh by a partitioning of the serial mesh. Refine
// this mesh further in parallel to increase the resolution (1 time by
// default, or specified on the command line with -rp). Once the parallel
// mesh is defined, the serial mesh can be deleted.
ParMesh pmesh(MPI_COMM_WORLD, *mesh);
delete mesh;
for (int lev = 0; lev < par_ref_levels; lev++)
{
pmesh.UniformRefinement();
}
// 6. Define a parallel finite element space on the parallel mesh. Here we
// use the Nedelec finite elements of the specified order.
FiniteElementCollection *fec = NULL;
if (dim == 1)
{
fec = new ND_R1D_FECollection(order, dim);
}
else if (dim == 2)
{
fec = new ND_R2D_FECollection(order, dim);
}
else
{
fec = new ND_FECollection(order, dim);
}
ParFiniteElementSpace fespace(&pmesh, fec);
HYPRE_Int size = fespace.GlobalTrueVSize();
if (Mpi::Root()) { cout << "Number of H(Curl) unknowns: " << size << endl; }
// 7. Determine the list of true (i.e. parallel conforming) essential
// boundary dofs. In this example, the boundary conditions are defined
// by marking all the boundary attributes from the mesh as essential
// (Dirichlet) and converting them to a list of true dofs.
Array<int> ess_tdof_list;
if (pmesh.bdr_attributes.Size())
{
Array<int> ess_bdr(pmesh.bdr_attributes.Max());
ess_bdr = 1;
fespace.GetEssentialTrueDofs(ess_bdr, ess_tdof_list);
}
// 8. Set up the parallel linear form b(.) which corresponds to the
// right-hand side of the FEM linear system, which in this case is
// (f,phi_i) where f is given by the function f_exact and phi_i are the
// basis functions in the finite element fespace.
VectorFunctionCoefficient f(3, f_exact);
ParLinearForm b(&fespace);
b.AddDomainIntegrator(new VectorFEDomainLFIntegrator(f));
b.Assemble();
// 9. Define the solution vector x as a parallel finite element grid function
// corresponding to fespace. Initialize x by projecting the exact
// solution. Note that only values from the boundary edges will be used
// when eliminating the non-homogeneous boundary condition to modify the
// r.h.s. vector b.
ParGridFunction sol(&fespace);
VectorFunctionCoefficient E(3, E_exact);
VectorFunctionCoefficient CurlE(3, CurlE_exact);
sol.ProjectCoefficient(E);
// 10. Set up the parallel bilinear form corresponding to the EM diffusion
// operator curl muinv curl + sigma I, by adding the curl-curl and the
// mass domain integrators.
DenseMatrix sigmaMat(3);
sigmaMat(0,0) = 2.0; sigmaMat(1,1) = 2.0; sigmaMat(2,2) = 2.0;
sigmaMat(0,2) = 0.0; sigmaMat(2,0) = 0.0;
sigmaMat(0,1) = M_SQRT1_2; sigmaMat(1,0) = M_SQRT1_2; // 1/sqrt(2) in cmath
sigmaMat(1,2) = M_SQRT1_2; sigmaMat(2,1) = M_SQRT1_2;
ConstantCoefficient muinv(1.0);
MatrixConstantCoefficient sigma(sigmaMat);
ParBilinearForm a(&fespace);
a.AddDomainIntegrator(new CurlCurlIntegrator(muinv));
a.AddDomainIntegrator(new VectorFEMassIntegrator(sigma));
// 11. Assemble the parallel bilinear form and the corresponding linear
// system, applying any necessary transformations such as: parallel
// assembly, eliminating boundary conditions, applying conforming
// constraints for non-conforming AMR, etc.
a.Assemble();
OperatorPtr A;
Vector B, X;
a.FormLinearSystem(ess_tdof_list, sol, b, A, X, B);
// 12. Solve the system AX=B using PCG with the AMS preconditioner from hypre
if (use_ams)
{
if (Mpi::Root())
{
cout << "Size of linear system: "
<< A.As<HypreParMatrix>()->GetGlobalNumRows() << endl;
}
HypreAMS ams(*A.As<HypreParMatrix>(), &fespace);
HyprePCG pcg(*A.As<HypreParMatrix>());
pcg.SetTol(1e-12);
pcg.SetMaxIter(1000);
pcg.SetPrintLevel(2);
pcg.SetPreconditioner(ams);
pcg.Mult(B, X);
}
else
#ifdef MFEM_USE_SUPERLU
{
if (Mpi::Root())
{
cout << "Size of linear system: "
<< A.As<HypreParMatrix>()->GetGlobalNumRows() << endl;
}
SuperLURowLocMatrix A_SuperLU(*A.As<HypreParMatrix>());
SuperLUSolver AInv(MPI_COMM_WORLD);
AInv.SetOperator(A_SuperLU);
AInv.Mult(B,X);
}
#else
{
if (Mpi::Root()) { cout << "No solvers available." << endl; }
return 1;
}
#endif
// 13. Recover the parallel grid function corresponding to X. This is the
// local finite element solution on each processor.
a.RecoverFEMSolution(X, b, sol);
// 14. Compute and print the H(Curl) norm of the error.
{
real_t error = sol.ComputeHCurlError(&E, &CurlE);
if (Mpi::Root())
{
cout << "\n|| E_h - E ||_{H(Curl)} = " << error << '\n' << endl;
}
}
// 15. Save the refined mesh and the solution in parallel. This output can
// be viewed later using GLVis: "glvis -np <np> -m mesh -g sol".
{
ostringstream mesh_name, sol_name;
mesh_name << "mesh." << setfill('0') << setw(6) << myid;
sol_name << "sol." << setfill('0') << setw(6) << myid;
ofstream mesh_ofs(mesh_name.str().c_str());
mesh_ofs.precision(8);
pmesh.Print(mesh_ofs);
ofstream sol_ofs(sol_name.str().c_str());
sol_ofs.precision(8);
sol.Save(sol_ofs);
}
// 16. Send the solution by socket to a GLVis server.
if (visualization)
{
char vishost[] = "localhost";
int visport = 19916;
VectorGridFunctionCoefficient solCoef(&sol);
CurlGridFunctionCoefficient dsolCoef(&sol);
if (dim ==1)
{
socketstream x_sock(vishost, visport);
socketstream y_sock(vishost, visport);
socketstream z_sock(vishost, visport);
socketstream dy_sock(vishost, visport);
socketstream dz_sock(vishost, visport);
x_sock.precision(8);
y_sock.precision(8);
z_sock.precision(8);
dy_sock.precision(8);
dz_sock.precision(8);
Vector xVec(3); xVec = 0.0; xVec(0) = 1;
Vector yVec(3); yVec = 0.0; yVec(1) = 1;
Vector zVec(3); zVec = 0.0; zVec(2) = 1;
VectorConstantCoefficient xVecCoef(xVec);
VectorConstantCoefficient yVecCoef(yVec);
VectorConstantCoefficient zVecCoef(zVec);
H1_FECollection fec_h1(order, dim);
L2_FECollection fec_l2(order-1, dim);
ParFiniteElementSpace fes_h1(&pmesh, &fec_h1);
ParFiniteElementSpace fes_l2(&pmesh, &fec_l2);
ParGridFunction xComp(&fes_l2);
ParGridFunction yComp(&fes_h1);
ParGridFunction zComp(&fes_h1);
ParGridFunction dyComp(&fes_l2);
ParGridFunction dzComp(&fes_l2);
InnerProductCoefficient xCoef(xVecCoef, solCoef);
InnerProductCoefficient yCoef(yVecCoef, solCoef);
InnerProductCoefficient zCoef(zVecCoef, solCoef);
xComp.ProjectCoefficient(xCoef);
yComp.ProjectCoefficient(yCoef);
zComp.ProjectCoefficient(zCoef);
x_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << xComp << flush
<< "window_title 'X component'" << endl;
y_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << yComp << flush
<< "window_geometry 403 0 400 350 "
<< "window_title 'Y component'" << endl;
z_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << zComp << flush
<< "window_geometry 806 0 400 350 "
<< "window_title 'Z component'" << endl;
InnerProductCoefficient dyCoef(yVecCoef, dsolCoef);
InnerProductCoefficient dzCoef(zVecCoef, dsolCoef);
dyComp.ProjectCoefficient(dyCoef);
dzComp.ProjectCoefficient(dzCoef);
dy_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << dyComp << flush
<< "window_geometry 403 375 400 350 "
<< "window_title 'Y component of Curl'" << endl;
dz_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << dzComp << flush
<< "window_geometry 806 375 400 350 "
<< "window_title 'Z component of Curl'" << endl;
}
else if (dim == 2)
{
socketstream xy_sock(vishost, visport);
socketstream z_sock(vishost, visport);
socketstream dxy_sock(vishost, visport);
socketstream dz_sock(vishost, visport);
DenseMatrix xyMat(2,3); xyMat = 0.0;
xyMat(0,0) = 1.0; xyMat(1,1) = 1.0;
MatrixConstantCoefficient xyMatCoef(xyMat);
Vector zVec(3); zVec = 0.0; zVec(2) = 1;
VectorConstantCoefficient zVecCoef(zVec);
MatrixVectorProductCoefficient xyCoef(xyMatCoef, solCoef);
InnerProductCoefficient zCoef(zVecCoef, solCoef);
H1_FECollection fec_h1(order, dim);
ND_FECollection fec_nd(order, dim);
RT_FECollection fec_rt(order-1, dim);
L2_FECollection fec_l2(order-1, dim);
ParFiniteElementSpace fes_h1(&pmesh, &fec_h1);
ParFiniteElementSpace fes_nd(&pmesh, &fec_nd);
ParFiniteElementSpace fes_rt(&pmesh, &fec_rt);
ParFiniteElementSpace fes_l2(&pmesh, &fec_l2);
ParGridFunction xyComp(&fes_nd);
ParGridFunction zComp(&fes_h1);
ParGridFunction dxyComp(&fes_rt);
ParGridFunction dzComp(&fes_l2);
xyComp.ProjectCoefficient(xyCoef);
zComp.ProjectCoefficient(zCoef);
xy_sock << "parallel " << num_procs << " " << myid << "\n";
xy_sock.precision(8);
xy_sock << "solution\n" << pmesh << xyComp
<< "window_title 'XY components'\n" << flush;
z_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << zComp << flush
<< "window_geometry 403 0 400 350 "
<< "window_title 'Z component'" << endl;
MatrixVectorProductCoefficient dxyCoef(xyMatCoef, dsolCoef);
InnerProductCoefficient dzCoef(zVecCoef, dsolCoef);
dxyComp.ProjectCoefficient(dxyCoef);
dzComp.ProjectCoefficient(dzCoef);
dxy_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << dxyComp << flush
<< "window_geometry 0 375 400 350 "
<< "window_title 'XY components of Curl'" << endl;
dz_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << dzComp << flush
<< "window_geometry 403 375 400 350 "
<< "window_title 'Z component of Curl'" << endl;
}
else
{
socketstream sol_sock(vishost, visport);
socketstream dsol_sock(vishost, visport);
RT_FECollection fec_rt(order-1, dim);
ParFiniteElementSpace fes_rt(&pmesh, &fec_rt);
ParGridFunction dsol(&fes_rt);
dsol.ProjectCoefficient(dsolCoef);
sol_sock << "parallel " << num_procs << " " << myid << "\n";
sol_sock.precision(8);
sol_sock << "solution\n" << pmesh << sol
<< "window_title 'Solution'" << flush << endl;
dsol_sock << "parallel " << num_procs << " " << myid << "\n"
<< "solution\n" << pmesh << dsol << flush
<< "window_geometry 0 375 400 350 "
<< "window_title 'Curl of solution'" << endl;
}
}
// 17. Free the used memory.
delete fec;
return 0;
}
void E_exact(const Vector &x, Vector &E)
{
if (dim == 1)
{
E(0) = 1.1 * sin(kappa * x(0) + 0.0 * M_PI);
E(1) = 1.2 * sin(kappa * x(0) + 0.4 * M_PI);
E(2) = 1.3 * sin(kappa * x(0) + 0.9 * M_PI);
}
else if (dim == 2)
{
E(0) = 1.1 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
E(1) = 1.2 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
E(2) = 1.3 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
}
else
{
E(0) = 1.1 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
E(1) = 1.2 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
E(2) = 1.3 * sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
E *= cos(kappa * x(2));
}
}
void CurlE_exact(const Vector &x, Vector &dE)
{
if (dim == 1)
{
real_t c4 = cos(kappa * x(0) + 0.4 * M_PI);
real_t c9 = cos(kappa * x(0) + 0.9 * M_PI);
dE(0) = 0.0;
dE(1) = -1.3 * c9;
dE(2) = 1.2 * c4;
dE *= kappa;
}
else if (dim == 2)
{
real_t c0 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t c4 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t c9 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
dE(0) = 1.3 * c9;
dE(1) = -1.3 * c9;
dE(2) = 1.2 * c4 - 1.1 * c0;
dE *= kappa * M_SQRT1_2;
}
else
{
real_t s0 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t c0 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t s4 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t c4 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t c9 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
real_t sk = sin(kappa * x(2));
real_t ck = cos(kappa * x(2));
dE(0) = 1.2 * s4 * sk + 1.3 * M_SQRT1_2 * c9 * ck;
dE(1) = -1.1 * s0 * sk - 1.3 * M_SQRT1_2 * c9 * ck;
dE(2) = -M_SQRT1_2 * (1.1 * c0 - 1.2 * c4) * ck;
dE *= kappa;
}
}
void f_exact(const Vector &x, Vector &f)
{
if (dim == 1)
{
real_t s0 = sin(kappa * x(0) + 0.0 * M_PI);
real_t s4 = sin(kappa * x(0) + 0.4 * M_PI);
real_t s9 = sin(kappa * x(0) + 0.9 * M_PI);
f(0) = 2.2 * s0 + 1.2 * M_SQRT1_2 * s4;
f(1) = 1.2 * (2.0 + kappa * kappa) * s4 +
M_SQRT1_2 * (1.1 * s0 + 1.3 * s9);
f(2) = 1.3 * (2.0 + kappa * kappa) * s9 + 1.2 * M_SQRT1_2 * s4;
}
else if (dim == 2)
{
real_t s0 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t s4 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t s9 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
f(0) = 0.55 * (4.0 + kappa * kappa) * s0 +
0.6 * (M_SQRT2 - kappa * kappa) * s4;
f(1) = 0.55 * (M_SQRT2 - kappa * kappa) * s0 +
0.6 * (4.0 + kappa * kappa) * s4 +
0.65 * M_SQRT2 * s9;
f(2) = 0.6 * M_SQRT2 * s4 + 1.3 * (2.0 + kappa * kappa) * s9;
}
else
{
real_t s0 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t c0 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.0 * M_PI);
real_t s4 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t c4 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.4 * M_PI);
real_t s9 = sin(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
real_t c9 = cos(kappa * M_SQRT1_2 * (x(0) + x(1)) + 0.9 * M_PI);
real_t sk = sin(kappa * x(2));
real_t ck = cos(kappa * x(2));
f(0) = 0.55 * (4.0 + 3.0 * kappa * kappa) * s0 * ck +
0.6 * (M_SQRT2 - kappa * kappa) * s4 * ck -
0.65 * M_SQRT2 * kappa * kappa * c9 * sk;
f(1) = 0.55 * (M_SQRT2 - kappa * kappa) * s0 * ck +
0.6 * (4.0 + 3.0 * kappa * kappa) * s4 * ck +
0.65 * M_SQRT2 * s9 * ck -
0.65 * M_SQRT2 * kappa * kappa * c9 * sk;
f(2) = 0.6 * M_SQRT2 * s4 * ck -
M_SQRT2 * kappa * kappa * (0.55 * c0 + 0.6 * c4) * sk
+ 1.3 * (2.0 + kappa * kappa) * s9 * ck;
}
}