Sheet 7

2026-01-06 14:05:44 +01:00 · 2026-01-06 14:05:44 +01:00 · 4c92446409
commit 4c92446409
parent 33c18c8808
74 changed files with 169041 additions and 0 deletions
--- a/sheet7/jacobi.template/main.cpp
+++ b/sheet7/jacobi.template/main.cpp
@ -0,0 +1,94 @@
+//		MPI code in C++.
+//		See [Gropp/Lusk/Skjellum, "Using MPI", p.33/41 etc.]
+//		and  /opt/mpich/include/mpi2c++/comm.h  for details
+
+#include "geom.h"
+#include "getmatrix.h"
+#include "jacsolve.h"
+#include "par_geom.h"
+#include "userset.h"
+#include "vdop.h"
+
+#include <cmath>
+#include <iostream>
+#include <mpi.h>            // MPI
+#include <omp.h>            // OpenMP
+using namespace std;
+
+
+int main(int argc , char **argv )
+{
+    MPI_Init(&argc, &argv);
+    MPI_Comm const icomm(MPI_COMM_WORLD);
+    omp_set_num_threads(1);                   // don't use OMP parallelization for a start
+//
+    {
+        int np;
+        MPI_Comm_size(icomm, &np);
+
+        //assert(4 == np);                  // example is only provided for 4 MPI processes
+    }
+// #####################################################################
+// ---- Read the f.e. mesh and the mapping of elements to MPI processes
+    //Mesh const mesh_c("square_4.txt");    //    Files square_4.m and square_4_sd.txt  are needed
+    //ParMesh const mesh("square_bb");
+    ParMesh const mesh("../generate_mesh/rec");
+    //ParMesh const mesh("../generate_mesh/rec_a");
+
+    int const numprocs = mesh.NumProcs();
+    int const myrank   = mesh.MyRank();
+    if ( 0 == myrank )
+    {
+        cout << "\n There are " << numprocs << " processes running.\n \n";
+    }
+
+    int const check_rank = 0;             // choose the MPI process you would like to check the mesh
+    //if ( check_rank == myrank ) mesh.Debug();
+    //if ( check_rank == myrank ) mesh.DebugEdgeBased();
+
+
+    FEM_Matrix SK(mesh);                   // CRS matrix
+    //SK.Debug();
+
+    vector<double> uv(SK.Nrows(), 0.0);    // temperature
+    vector<double> fv(SK.Nrows(), 0.0);    // r.h.s.
+
+    mesh.VecAccu(uv);                      // Check MPI comm.
+
+    SK.CalculateLaplace(fv);
+    //SK.Debug();
+    //
+    mesh.SetValues(uv, [](double x, double y) -> double
+    {
+        return x *x * std::sin(2.5 * M_PI * y);
+    } );
+
+    ////mesh.SetU(uv);         // deprecated
+    //// Two ways to initialize the vector
+    ////mesh.SetValues(uv,f_zero);             // user function
+    ////mesh.SetValues(uv, [](double x, double y) -> double {return 0.0*x*y;} );  // lambda function
+    ////mesh.SetValues(uv, [](double x, double y) -> double {return 5e-3*(x+1)*(y+1);} );  // lambda function
+    ////
+    //mesh.SetValues(uv, [](double x, double y) -> double {
+    //return x * x * std::sin(2.5 * M_PI * y);
+    //} );
+
+    SK.ApplyDirichletBC(uv, fv);
+    //SK.Debug();
+
+    double tstart = MPI_Wtime();                  // Wall clock
+
+    JacobiSolve(SK, fv, uv );          // solve the system of equations
+    //JacobiSolve(mesh, SK, fv, uv );          // MPI: solve the system of equations
+
+    double t1 =  MPI_Wtime() - tstart;             // Wall clock
+    cout << "JacobiSolve: timing in sec. : " << t1 << endl;
+
+    //if (2==myrank || (1==numprocs && 0==myrank) ) mesh.Mesh::Visualize(uv);  // Visualize only one subdomain
+    mesh.Visualize(uv);       // Visualize all subdomains
+
+    MPI_Finalize();
+    return 0;
+}
+
+