331 lines
12 KiB
C++
331 lines
12 KiB
C++
// MFEM Example 39 - Parallel Version
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//
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// Compile with: make ex39p
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//
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// Sample runs: mpirun -np 4 ex39p
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// mpirun -np 4 ex39p -ess "Southern Boundary"
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// mpirun -np 4 ex39p -src Base
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//
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// Device sample runs:
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// mpirun -np 4 ex39p -fa -d cuda
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//
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// Description: This example code demonstrates the use of named attribute
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// sets in MFEM to specify material regions, boundary regions,
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// or source regions by name rather than attribute numbers. It
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// also demonstrates how new named attribute sets may be created
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// from arbitrary groupings of attribute number and used as a
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// convenient shorthand to refer to those groupings in other
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// portions of the application or through the command line.
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//
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// The particular problem being solved here is nearly the same
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// as that in example 1 i.e. a simple finite element
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// discretization of the Laplace problem -Delta u = 1 with
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// homogeneous Dirichlet boundary conditions and, in this case,
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// an inhomogeneous diffusion coefficient. The diffusion
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// coefficient is given a small default value throughout the
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// domain which is increased by two separate amounts in two named
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// regions.
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//
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// The example highlights the use of named attribute sets for
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// both subdomains and boundaries in different contexts as well
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// as basic methods to create named sets from existing attributes.
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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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Hypre::Init();
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// 2. Parse command-line options.
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const char *mesh_file = "../data/compass.msh";
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int order = 1;
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string source_name = "Rose Even";
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string ess_name = "Boundary";
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bool visualization = true;
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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(&source_name,"-src","--source-attr-name",
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"Name of attribute set containing source.");
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args.AddOption(&ess_name,"-ess","--ess-attr-name",
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"Name of attribute set containing essential BC.");
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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 (Mpi::Root())
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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 (Mpi::Root())
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{
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args.PrintOptions(cout);
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}
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// 3. Read the serial mesh from the given mesh file.
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Mesh mesh(mesh_file, 1, 1);
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int dim = mesh.Dimension();
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// 4. 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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// 5. 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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// 6a. Display attribute set names contained in the initial mesh
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AttributeSets &attr_sets = pmesh.attribute_sets;
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if (Mpi::Root())
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{
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std::set<string> names = attr_sets.GetAttributeSetNames();
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cout << "Element Attribute Set Names: ";
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for (auto const &set_name : names)
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{
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cout << " \"" << set_name << "\"";
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}
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cout << endl;
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std::set<string> bdr_names = attr_sets.GetBdrAttributeSetNames();
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cout << "Boundary Attribute Set Names: ";
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for (auto const &bdr_set_name : bdr_names)
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{
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cout << " \"" << bdr_set_name << "\"";
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}
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cout << endl;
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}
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// 6b. Define new regions based on existing attribute sets
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{
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Array<int> & Na = attr_sets.GetAttributeSet("N Even");
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Array<int> & Nb = attr_sets.GetAttributeSet("N Odd");
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Array<int> & Sa = attr_sets.GetAttributeSet("S Even");
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Array<int> & Sb = attr_sets.GetAttributeSet("S Odd");
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Array<int> & Ea = attr_sets.GetAttributeSet("E Even");
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Array<int> & Eb = attr_sets.GetAttributeSet("E Odd");
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Array<int> & Wa = attr_sets.GetAttributeSet("W Even");
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Array<int> & Wb = attr_sets.GetAttributeSet("W Odd");
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// Create a new set spanning the North point
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attr_sets.SetAttributeSet("North", Na);
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attr_sets.AddToAttributeSet("North", Nb);
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// Create a new set spanning the South point
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attr_sets.SetAttributeSet("South", Sa);
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attr_sets.AddToAttributeSet("South", Sb);
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// Create a new set spanning the East point
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attr_sets.SetAttributeSet("East", Ea);
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attr_sets.AddToAttributeSet("East", Eb);
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// Create a new set spanning the West point
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attr_sets.SetAttributeSet("West", Wa);
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attr_sets.AddToAttributeSet("West", Wb);
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// Create a new set consisting of the "a" sides of the compass rose
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attr_sets.SetAttributeSet("Rose Even", Na);
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attr_sets.AddToAttributeSet("Rose Even", Sa);
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attr_sets.AddToAttributeSet("Rose Even", Ea);
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attr_sets.AddToAttributeSet("Rose Even", Wa);
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// Create a new set consisting of the "b" sides of the compass rose
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attr_sets.SetAttributeSet("Rose Odd", Nb);
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attr_sets.AddToAttributeSet("Rose Odd", Sb);
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attr_sets.AddToAttributeSet("Rose Odd", Eb);
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attr_sets.AddToAttributeSet("Rose Odd", Wb);
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// Create a new set consisting of the full compass rose
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Array<int> & Ra = attr_sets.GetAttributeSet("Rose Even");
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Array<int> & Rb = attr_sets.GetAttributeSet("Rose Odd");
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attr_sets.SetAttributeSet("Rose", Ra);
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attr_sets.AddToAttributeSet("Rose", Rb);
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}
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// 6c. Define new boundary regions based on existing boundary attribute sets
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{
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Array<int> & NNE = attr_sets.GetBdrAttributeSet("NNE");
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Array<int> & NNW = attr_sets.GetBdrAttributeSet("NNW");
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Array<int> & ENE = attr_sets.GetBdrAttributeSet("ENE");
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Array<int> & ESE = attr_sets.GetBdrAttributeSet("ESE");
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Array<int> & SSE = attr_sets.GetBdrAttributeSet("SSE");
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Array<int> & SSW = attr_sets.GetBdrAttributeSet("SSW");
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Array<int> & WNW = attr_sets.GetBdrAttributeSet("WNW");
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Array<int> & WSW = attr_sets.GetBdrAttributeSet("WSW");
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attr_sets.SetBdrAttributeSet("Northern Boundary", NNE);
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attr_sets.AddToBdrAttributeSet("Northern Boundary", NNW);
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attr_sets.SetBdrAttributeSet("Southern Boundary", SSE);
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attr_sets.AddToBdrAttributeSet("Southern Boundary", SSW);
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attr_sets.SetBdrAttributeSet("Eastern Boundary", ENE);
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attr_sets.AddToBdrAttributeSet("Eastern Boundary", ESE);
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attr_sets.SetBdrAttributeSet("Western Boundary", WNW);
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attr_sets.AddToBdrAttributeSet("Western Boundary", WSW);
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attr_sets.SetBdrAttributeSet("Boundary",
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attr_sets.GetBdrAttributeSet
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("Northern Boundary"));
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attr_sets.AddToBdrAttributeSet("Boundary",
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attr_sets.GetBdrAttributeSet
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("Southern Boundary"));
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attr_sets.AddToBdrAttributeSet("Boundary",
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attr_sets.GetBdrAttributeSet
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("Eastern Boundary"));
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attr_sets.AddToBdrAttributeSet("Boundary",
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attr_sets.GetBdrAttributeSet
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("Western Boundary"));
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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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H1_FECollection fec(order, dim);
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ParFiniteElementSpace fespace(&pmesh, &fec);
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HYPRE_BigInt size = fespace.GlobalTrueVSize();
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if (Mpi::Root())
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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 boundary regions corresponding to the boundary
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// attributes contained in the set named "ess_name" as essential
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// (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_marker;
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pmesh.BdrAttrToMarker(attr_sets.GetBdrAttributeSet(ess_name),
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ess_bdr_marker);
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fespace.GetEssentialTrueDofs(ess_bdr_marker, 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_s,phi_i) where phi_i are the basis functions in fespace and 1_s
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// is an indicator function equal to 1 on the region defined by the
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// named set "source_name" and zero elsewhere.
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Array<int> source_marker;
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pmesh.AttrToMarker(attr_sets.GetAttributeSet(source_name), source_marker);
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ParLinearForm b(&fespace);
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ConstantCoefficient one(1.0);
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b.AddDomainIntegrator(new DomainLFIntegrator(one), source_marker);
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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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ConstantCoefficient defaultCoef(1.0e-6);
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ConstantCoefficient baseCoef(1.0);
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ConstantCoefficient roseCoef(2.0);
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Array<int> base_marker;
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Array<int> rose_marker;
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pmesh.AttrToMarker(attr_sets.GetAttributeSet("Base"), base_marker);
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pmesh.AttrToMarker(attr_sets.GetAttributeSet("Rose Even"), rose_marker);
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a.AddDomainIntegrator(new DiffusionIntegrator(defaultCoef));
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a.AddDomainIntegrator(new DiffusionIntegrator(baseCoef), base_marker);
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a.AddDomainIntegrator(new DiffusionIntegrator(roseCoef), rose_marker);
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// 12. Assemble the parallel bilinear form and the corresponding linear
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// system, applying any necessary transformations.
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a.Assemble();
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HypreParMatrix 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 system using PCG with hypre's BoomerAMG preconditioner.
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HypreBoomerAMG M(A);
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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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cg.SetPreconditioner(M);
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cg.SetOperator(A);
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cg.Mult(B, X);
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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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int myid = Mpi::WorldRank();
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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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int num_procs = Mpi::WorldSize();
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int myid = Mpi::WorldRank();
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socketstream sol_sock(vishost, visport);
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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 << "keys Rjmm" << flush;
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}
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return 0;
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}
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