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2026-01-09 16:20:37 +01:00 · 2026-01-09 16:20:37 +01:00 · 2c68479c21
commit 2c68479c21
parent 21645b65bc
5 changed files with 1615 additions and 0 deletions
--- a/Sheet7/Ex_9to13/accu_template/main.cpp
+++ b/Sheet7/Ex_9to13/accu_template/main.cpp
@ -0,0 +1,108 @@
+//		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 "par_geom.h"
+#include "vdop.h"
+
+#include <cassert>
+#include <cmath>
+#include <iostream>
+#include <mpi.h>            // MPI
+//#include <omp.h>            // OpenMP, for E9 it is not necessary
+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.txt and square_4_sd.txt  are needed
+    ParMesh const mesh("square",icomm);
+    
+    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();
+    
+// ---- allocate local vectors and check skalar product and vector accumulation
+    vector<double> xl(mesh.Nnodes(), 1.0);
+    mesh.SetValues(xl, [](double x, double y) -> double {return x * x * std::sin(2.5 * M_PI * y);} );
+    
+    //E9
+    if (myrank == check_rank){
+        cout << "E9" << endl;
+    }
+
+    double ss = mesh.dscapr(xl,xl);
+    if (myrank == check_rank){
+        cout << myrank << " : scalar : " << ss << endl << endl;
+    }
+
+    mesh.VecAccu(xl);
+
+    //E10
+    if (myrank == check_rank){
+        cout << "E10" << endl;
+    }
+    vector<int> xl_int(mesh.Nnodes(), 1);
+
+    // check accumulation (by console output)
+    mesh.VecAccu(xl_int);
+
+    vector<double> coords = mesh.GetCoords();
+    if (check_rank == myrank){
+        for (size_t i = 0; i < coords.size(); i += 2){
+            cout << "(" << coords[i] << ", " << coords[i + 1] << "):\t" << xl_int[i/2] << endl;
+        }
+    }
+
+    //E11
+    if (myrank == check_rank){
+        cout << "E11" << endl;
+    }
+    int global_nodes = mesh.GlobalNodes();
+    if (check_rank == myrank){
+        cout << "Global nodes: " << global_nodes << endl;
+    }
+
+    //E12
+    if (myrank == check_rank){
+        cout << "E12" << endl;
+    }
+    vector<double> xl_new(mesh.Nnodes(), 1.0);
+
+    mesh.Average(xl_new);
+
+
+
+
+
+
+
+
+
+
+
+
+    MPI_Finalize();
+    return 0;
+}
+
+