133 lines
4.3 KiB
C++
133 lines
4.3 KiB
C++
#include "check_env.h"
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#include "mylib.h"
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#include <cstdlib> // atoi()
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#include <cstring> // strncmp()
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#include <ctime>
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#include <iostream>
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#include <omp.h> // OpenMP
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#include <sstream>
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#include <string>
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using namespace std;
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int main(int argc, char const *argv[])
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{
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//int const NLOOPS = 5; // chose a value such that the benchmark runs at least 10 sec.
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//unsigned int N = 500000001; // to less memory :(
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int const NLOOPS = 50; // chose a value such that the benchmark runs at least 10 sec.
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unsigned int N = 50000001;
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//##########################################################################
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// Read Parameter from command line (C++ style)
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cout << "Checking command line parameters for: -n <number> " << endl;
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for (int i = 1; i < argc; i++)
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{
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cout << " arg[" << i << "] = " << argv[i] << endl;
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string ss(argv[i]);
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if ("-n"==ss && i + 1 < argc) // found "-n" followed by another parameter
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{
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N = static_cast<unsigned int>(atoi(argv[i + 1]));
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}
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else
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{
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cout << "Corect call: " << argv[0] << " -n <number>\n";
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}
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}
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cout << "\nN = " << N << endl;
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check_env(argc, argv);
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//########################################################################
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//omp_set_num_threads(16);
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int nthreads; // OpenMP
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int numproc = omp_get_num_procs();
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cout << "Es stehen maximal " << numproc << " Kerne zur Verfuegung" << endl;
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#pragma omp parallel default(none) shared(cout,nthreads)
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{
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int const th_id = omp_get_thread_num(); // OpenMP
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int const nthrds = omp_get_num_threads(); // OpenMP
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stringstream ss;
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ss << "C++: Hello World from thread " << th_id << " / " << nthrds << endl;
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#pragma omp critical
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{
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cout << ss.str(); // output to a shared ressource
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}
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#pragma omp master
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nthreads = nthrds; // transfer nn to to master thread
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}
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cout << " " << nthreads << " threads have been started." << endl;
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//##########################################################################
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// Memory allocation
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cout << "Memory allocation\n";
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vector<double> x(N), y(N);
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cout.precision(2);
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cout << 2.0 * N *sizeof(x[0]) / 1024 / 1024 / 1024 << " GByte Memory allocated\n";
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cout.precision(6);
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//##########################################################################
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// Data initialization
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// Special: x_i = i+1; y_i = 1/x_i ==> <x,y> == N
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for (unsigned int i = 0; i < N; ++i)
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{
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x[i] = i + 1;
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y[i] = 1.0 / x[i];
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}
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//##########################################################################
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cout << "\nStart Benchmarking\n";
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// Do calculation
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double tstart = omp_get_wtime(); // OpenMP
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double sk(0.0);
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for (int i = 0; i < NLOOPS; ++i)
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{
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sk = scalar(x, y);
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sk = scalar_trans(x, y);
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//sk = norm(x);
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//sk = scalar_manual(x,y);
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}
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double t1 = omp_get_wtime() - tstart; // OpenMP
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t1 /= NLOOPS; // divide by number of function calls
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//##########################################################################
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// Check the correct result
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cout << "\n <x,y> = " << sk << endl;
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if (static_cast<unsigned int>(sk) != N)
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{
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cout << " !! W R O N G result !!\n";
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}
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cout << endl;
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//##########################################################################
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// Timings and Performance
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cout << endl;
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cout.precision(2);
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cout << "Timing in sec. : " << t1 << endl;
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cout << "GFLOPS : " << 2.0 * N / t1 / 1024 / 1024 / 1024 << endl;
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cout << "GiByte/s : " << 2.0 * N / t1 / 1024 / 1024 / 1024 * sizeof(x[0]) << endl;
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//#########################################################################
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cout << "\n Try the reduction with an STL-vektor (adding)\n";
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auto vr = reduction_vec(100);
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cout << "done\n";
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cout << vr << endl;
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//#########################################################################
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cout << "\n Try the reduction with an STL-vektor (appending)\n";
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auto vra = reduction_vec_append(10);
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cout << "done\n";
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cout << vra << endl;
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return 0;
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} // memory for x and y will be deallocated their destructors
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