318 lines
12 KiB
C++
318 lines
12 KiB
C++
// MFEM Example 1 - Parallel Version
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//
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// Compile with: make ex1p
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//
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// Sample runs: mpirun -np 4 ex1p -m ../data/square-disc.mesh
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// mpirun -np 4 ex1p -m ../data/star.mesh
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// mpirun -np 4 ex1p -m ../data/star-mixed.mesh
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// mpirun -np 4 ex1p -m ../data/escher.mesh
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// mpirun -np 4 ex1p -m ../data/fichera.mesh
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// mpirun -np 4 ex1p -m ../data/fichera-mixed.mesh
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// mpirun -np 4 ex1p -m ../data/toroid-wedge.mesh
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// mpirun -np 4 ex1p -m ../data/octahedron.mesh -o 1
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// mpirun -np 4 ex1p -m ../data/periodic-annulus-sector.msh
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// mpirun -np 4 ex1p -m ../data/periodic-torus-sector.msh
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// mpirun -np 4 ex1p -m ../data/square-disc-p2.vtk -o 2
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// mpirun -np 4 ex1p -m ../data/square-disc-p3.mesh -o 3
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// mpirun -np 4 ex1p -m ../data/square-disc-nurbs.mesh -o -1
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// mpirun -np 4 ex1p -m ../data/star-mixed-p2.mesh -o 2
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// mpirun -np 4 ex1p -m ../data/disc-nurbs.mesh -o -1
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// mpirun -np 4 ex1p -m ../data/pipe-nurbs.mesh -o -1
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// mpirun -np 4 ex1p -m ../data/ball-nurbs.mesh -o 2
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// mpirun -np 4 ex1p -m ../data/fichera-mixed-p2.mesh -o 2
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// mpirun -np 4 ex1p -m ../data/star-surf.mesh
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// mpirun -np 4 ex1p -m ../data/square-disc-surf.mesh
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// mpirun -np 4 ex1p -m ../data/inline-segment.mesh
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// mpirun -np 4 ex1p -m ../data/amr-quad.mesh
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// mpirun -np 4 ex1p -m ../data/amr-hex.mesh
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// mpirun -np 4 ex1p -m ../data/mobius-strip.mesh
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// mpirun -np 4 ex1p -m ../data/mobius-strip.mesh -o -1 -sc
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//
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// Device sample runs:
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// mpirun -np 4 ex1p -pa -d cuda
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// mpirun -np 4 ex1p -fa -d cuda
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// mpirun -np 4 ex1p -pa -d occa-cuda
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// mpirun -np 4 ex1p -pa -d raja-omp
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// mpirun -np 4 ex1p -pa -d ceed-cpu
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// mpirun -np 4 ex1p -pa -d ceed-cpu -o 4 -a
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// mpirun -np 4 ex1p -pa -d ceed-cpu -m ../data/square-mixed.mesh
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// mpirun -np 4 ex1p -pa -d ceed-cpu -m ../data/fichera-mixed.mesh
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// * mpirun -np 4 ex1p -pa -d ceed-cuda
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// * mpirun -np 4 ex1p -pa -d ceed-hip
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// mpirun -np 4 ex1p -pa -d ceed-cuda:/gpu/cuda/shared
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// mpirun -np 4 ex1p -pa -d ceed-cuda:/gpu/cuda/shared -m ../data/square-mixed.mesh
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// mpirun -np 4 ex1p -pa -d ceed-cuda:/gpu/cuda/shared -m ../data/fichera-mixed.mesh
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// mpirun -np 4 ex1p -m ../data/beam-tet.mesh -pa -d ceed-cpu
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//
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// Description: This example code demonstrates the use of MFEM to define a
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// simple finite element discretization of the Poisson problem
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// -Delta u = 1 with homogeneous Dirichlet boundary conditions.
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// Specifically, we discretize using a FE space of the specified
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// order, or if order < 1 using an isoparametric/isogeometric
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// space (i.e. quadratic for quadratic curvilinear mesh, NURBS for
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// NURBS mesh, etc.)
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//
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// The example highlights the use of mesh refinement, finite
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// element grid functions, as well as linear and bilinear forms
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// corresponding to the left-hand side and right-hand side of the
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// discrete linear system. We also cover the explicit elimination
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// of essential boundary conditions, static condensation, and the
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// optional connection to the GLVis tool for visualization.
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#include "mfem.hpp"
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#include <fstream>
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#include <iostream>
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using namespace std;
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using namespace mfem;
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int main(int argc, char *argv[])
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{
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// 1. Initialize MPI and HYPRE.
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Mpi::Init();
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int num_procs = Mpi::WorldSize();
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int myid = Mpi::WorldRank();
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Hypre::Init();
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// 2. Parse command-line options.
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const char *mesh_file = "../data/star.mesh";
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int order = 1;
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bool static_cond = false;
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bool pa = false;
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bool fa = false;
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const char *device_config = "cpu";
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bool visualization = true;
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bool algebraic_ceed = false;
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OptionsParser args(argc, argv);
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args.AddOption(&mesh_file, "-m", "--mesh",
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"Mesh file to use.");
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args.AddOption(&order, "-o", "--order",
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"Finite element order (polynomial degree) or -1 for"
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" isoparametric space.");
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args.AddOption(&static_cond, "-sc", "--static-condensation", "-no-sc",
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"--no-static-condensation", "Enable static condensation.");
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args.AddOption(&pa, "-pa", "--partial-assembly", "-no-pa",
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"--no-partial-assembly", "Enable Partial Assembly.");
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args.AddOption(&fa, "-fa", "--full-assembly", "-no-fa",
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"--no-full-assembly", "Enable Full Assembly.");
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args.AddOption(&device_config, "-d", "--device",
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"Device configuration string, see Device::Configure().");
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#ifdef MFEM_USE_CEED
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args.AddOption(&algebraic_ceed, "-a", "--algebraic",
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"-no-a", "--no-algebraic",
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"Use algebraic Ceed solver");
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#endif
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args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
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"--no-visualization",
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"Enable or disable GLVis visualization.");
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args.Parse();
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if (!args.Good())
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{
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if (myid == 0)
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{
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args.PrintUsage(cout);
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}
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return 1;
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}
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if (myid == 0)
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{
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args.PrintOptions(cout);
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}
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// 3. Enable hardware devices such as GPUs, and programming models such as
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// CUDA, OCCA, RAJA and OpenMP based on command line options.
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Device device(device_config);
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if (myid == 0) { device.Print(); }
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// 4. Read the (serial) mesh from the given mesh file on all processors. We
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// can handle triangular, quadrilateral, tetrahedral, hexahedral, surface
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// and volume meshes with the same code.
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Mesh mesh(mesh_file, 1, 1);
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int dim = mesh.Dimension();
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// 5. Refine the serial mesh on all processors to increase the resolution. In
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// this example we do 'ref_levels' of uniform refinement. We choose
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// 'ref_levels' to be the largest number that gives a final mesh with no
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// more than 10,000 elements.
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/*{
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int ref_levels =
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(int)floor(log(10000./mesh.GetNE())/log(2.)/dim);
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for (int l = 0; l < ref_levels; l++)
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{
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mesh.UniformRefinement();
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}
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}*/
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// 6. Define a parallel mesh by a partitioning of the serial mesh. Refine
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// this mesh further in parallel to increase the resolution. Once the
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// parallel mesh is defined, the serial mesh can be deleted.
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ParMesh pmesh(MPI_COMM_WORLD, mesh);
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mesh.Clear();
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{
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int par_ref_levels = 2;
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for (int l = 0; l < par_ref_levels; l++)
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{
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pmesh.UniformRefinement();
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}
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}
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// 7. Define a parallel finite element space on the parallel mesh. Here we
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// use continuous Lagrange finite elements of the specified order. If
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// order < 1, we instead use an isoparametric/isogeometric space.
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FiniteElementCollection *fec;
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bool delete_fec;
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if (order > 0)
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{
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fec = new H1_FECollection(order, dim);
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delete_fec = true;
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}
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else if (pmesh.GetNodes())
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{
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fec = pmesh.GetNodes()->OwnFEC();
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delete_fec = false;
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if (myid == 0)
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{
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cout << "Using isoparametric FEs: " << fec->Name() << endl;
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}
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}
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else
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{
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fec = new H1_FECollection(order = 1, dim);
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delete_fec = true;
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}
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ParFiniteElementSpace fespace(&pmesh, fec);
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HYPRE_BigInt size = fespace.GlobalTrueVSize();
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if (myid == 0)
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{
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cout << "Number of finite element unknowns: " << size << endl;
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}
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// 8. Determine the list of true (i.e. parallel conforming) essential
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// boundary dofs. In this example, the boundary conditions are defined
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// by marking all the external boundary attributes from the mesh as
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// essential (Dirichlet) and converting them to a list of true dofs.
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Array<int> ess_tdof_list;
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if (pmesh.bdr_attributes.Size())
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{
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Array<int> ess_bdr(pmesh.bdr_attributes.Max());
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ess_bdr = 0;
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// Apply boundary conditions on all external boundaries:
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pmesh.MarkExternalBoundaries(ess_bdr);
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// Boundary conditions can also be applied based on named attributes:
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// pmesh.MarkNamedBoundaries(set_name, ess_bdr)
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fespace.GetEssentialTrueDofs(ess_bdr, ess_tdof_list);
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}
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// 9. Set up the parallel linear form b(.) which corresponds to the
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// right-hand side of the FEM linear system, which in this case is
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// (1,phi_i) where phi_i are the basis functions in fespace.
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ParLinearForm b(&fespace);
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ConstantCoefficient one(1.0);
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b.AddDomainIntegrator(new DomainLFIntegrator(one));
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b.Assemble();
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// 10. Define the solution vector x as a parallel finite element grid
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// function corresponding to fespace. Initialize x with initial guess of
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// zero, which satisfies the boundary conditions.
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ParGridFunction x(&fespace);
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x = 0.0;
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// 11. Set up the parallel bilinear form a(.,.) on the finite element space
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// corresponding to the Laplacian operator -Delta, by adding the
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// Diffusion domain integrator.
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ParBilinearForm a(&fespace);
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if (pa) { a.SetAssemblyLevel(AssemblyLevel::PARTIAL); }
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if (fa)
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{
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a.SetAssemblyLevel(AssemblyLevel::FULL);
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// Sort the matrix column indices when running on GPU or with OpenMP (i.e.
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// when Device::IsEnabled() returns true). This makes the results
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// bit-for-bit deterministic at the cost of somewhat longer run time.
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a.EnableSparseMatrixSorting(Device::IsEnabled());
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}
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a.AddDomainIntegrator(new DiffusionIntegrator(one));
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// 12. Assemble the parallel bilinear form and the corresponding linear
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// system, applying any necessary transformations such as: parallel
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// assembly, eliminating boundary conditions, applying conforming
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// constraints for non-conforming AMR, static condensation, etc.
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if (static_cond) { a.EnableStaticCondensation(); }
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a.Assemble();
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OperatorPtr A;
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Vector B, X;
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a.FormLinearSystem(ess_tdof_list, x, b, A, X, B);
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// 13. Solve the linear system A X = B.
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// * With full assembly, use the BoomerAMG preconditioner from hypre.
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// * With partial assembly, use Jacobi smoothing, for now.
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Solver *prec = NULL;
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if (pa)
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{
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if (UsesTensorBasis(fespace))
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{
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if (algebraic_ceed)
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{
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prec = new ceed::AlgebraicSolver(a, ess_tdof_list);
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}
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else
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{
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prec = new OperatorJacobiSmoother(a, ess_tdof_list);
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}
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}
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}
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else
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{
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prec = new HypreBoomerAMG;
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}
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CGSolver cg(MPI_COMM_WORLD);
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cg.SetRelTol(1e-12);
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cg.SetMaxIter(2000);
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cg.SetPrintLevel(1);
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if (prec) { cg.SetPreconditioner(*prec); }
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cg.SetOperator(*A);
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cg.Mult(B, X);
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delete prec;
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// 14. Recover the parallel grid function corresponding to X. This is the
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// local finite element solution on each processor.
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a.RecoverFEMSolution(X, b, x);
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// 15. Save the refined mesh and the solution in parallel. This output can
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// be viewed later using GLVis: "glvis -np <np> -m mesh -g sol".
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/*{
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ostringstream mesh_name, sol_name;
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mesh_name << "mesh." << setfill('0') << setw(6) << myid;
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sol_name << "sol." << setfill('0') << setw(6) << myid;
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ofstream mesh_ofs(mesh_name.str().c_str());
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mesh_ofs.precision(8);
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pmesh.Print(mesh_ofs);
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ofstream sol_ofs(sol_name.str().c_str());
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sol_ofs.precision(8);
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x.Save(sol_ofs);
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}*/
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// 16. Send the solution by socket to a GLVis server.
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if (visualization)
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{
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char vishost[] = "localhost";
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int visport = 19916;
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glvis_stream sol_sock(vishost, visport, myid);
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sol_sock << "parallel " << num_procs << " " << myid << "\n";
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sol_sock.precision(8);
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sol_sock << "solution\n" << pmesh << x << flush;
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}
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// 17. Free the used memory.
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if (delete_fec)
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{
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delete fec;
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}
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return 0;
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}
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