108 lines
2.7 KiB
C++
108 lines
2.7 KiB
C++
// MPI code in C++.
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// See [Gropp/Lusk/Skjellum, "Using MPI", p.33/41 etc.]
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// and /opt/mpich/include/mpi2c++/comm.h for details
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#include "geom.h"
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#include "par_geom.h"
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#include "vdop.h"
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#include <cassert>
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#include <cmath>
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#include <iostream>
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#include <mpi.h> // MPI
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#include <omp.h> // OpenMP
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using namespace std;
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int main(int argc, char **argv )
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{
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MPI_Init(&argc, &argv);
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MPI_Comm const icomm(MPI_COMM_WORLD);
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omp_set_num_threads(1); // don't use OMP parallelization for a start
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//
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int np;
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MPI_Comm_size(icomm, &np);
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//assert(4 == np); // example is only provided for 4 MPI processes
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if(np == 4 || np ==2 || np == 1)
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{
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// #####################################################################
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// ---- Read the f.e. mesh and the mapping of elements to MPI processes
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//Mesh const mesh_c("square_4.txt"); // Files square_4.txt and square_4_sd.txt are needed
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ParMesh const mesh("square",icomm);
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int const numprocs = mesh.NumProcs();
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int const myrank = mesh.MyRank();
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if ( 0 == myrank ) {
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cout << "\n There are " << numprocs << " processes running.\n \n";
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}
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int const check_rank=0; // choose the MPI process you would like to check the mesh
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//if ( check_rank == myrank ) mesh.Debug();
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//if ( check_rank == myrank ) mesh.DebugEdgeBased();
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// ---- allocate local vectors and check skalar product and vector accumulation
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vector<double> xl(mesh.Nnodes(), -1.0);
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mesh.SetValues(xl, [](double x, double y) -> double {return x * x * std::sin(2.5 * M_PI * y);} );
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if (check_rank==myrank) mesh.Visualize(xl);
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cout << "nnodes: " <<mesh.Nnodes() << endl;
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for (size_t k=0; k<xl.size(); ++k)
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{
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xl[k] = 1.0;
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}
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double ss = mesh.dscapr(xl,xl);
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cout << myrank << " : scalar : " << ss << endl;
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mesh.VecAccu(xl);
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if (check_rank==myrank) mesh.Visualize(xl);
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//--------------------E10
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vector<int> x2(mesh.Nnodes(), -1);
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mesh.VecAccu(x2);
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if(myrank == check_rank)
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{
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for(int i: x2)
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{
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cout << i << " ";
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}
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cout << endl;
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}
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//-------------------E11
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int global_nodes = mesh.GlobalNnodes();
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if(myrank == check_rank)
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{
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cout << "Global number of nodes = " << global_nodes << endl;
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}
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//--------------------E12
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vector<double> x3(mesh.Nnodes(), myrank);
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// check averaging at the interfaces (by visualization)
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mesh.Average(x3);
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if (check_rank==myrank) mesh.Visualize(x3);
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}
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else
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{
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cout << np << endl;
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}
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MPI_Barrier(icomm);
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MPI_Finalize();
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return 0;
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}
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