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Lisa Pizzo 2025-12-02 09:35:37 +01:00
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//HOW TO RUN IT ON MY TERMINAL (MAC)
//export LDFLAGS="-L/opt/homebrew/opt/libomp/lib"
//export CPPFLAGS="-I/opt/homebrew/opt/libomp/include"
//clang++ -std=c++17 -O2 -Xpreprocessor -fopenmp $CPPFLAGS main.cpp mylib.cpp -L/opt/homebrew/opt/libomp/lib -lomp -o dotprod
//./dotprod
#include "check_env.h"
#include "mylib.h"
#include <cstdlib> // atoi()
#include <cstring> // strncmp()
#include <ctime>
#include <iostream>
#include <omp.h> // OpenMP
#include <sstream>
#include <string>
using namespace std;
int main(int argc, char const *argv[])
{
unsigned int N = 5000001; // smaller default for testing
int const NLOOPS = 5; // smaller loop for quick test
//##########################################################################
// Read Parameter from command line
cout << "=== Checking command line parameters ===" << endl;
for (int i = 1; i < argc; i++)
{
string ss(argv[i]);
if ("-n"==ss && i + 1 < argc)
N = static_cast<unsigned int>(atoi(argv[i + 1]));
else
cout << "Corect call: " << argv[0] << " -n <number>\n";
}
cout << "\nVector size N = " << N << endl;
//##########################################################################
check_env(argc, argv);
//##########################################################################
cout << "\n=== Starting OpenMP test ===" << endl;
int nthreads;
#pragma omp parallel default(none) shared(cout,nthreads)
{
int const th_id = omp_get_thread_num();
int const nthrds = omp_get_num_threads();
#pragma omp critical
cout << "Hello from thread " << th_id << " out of " << nthrds << endl;
#pragma omp master
nthreads = nthrds;
}
cout << "Total threads started: " << nthreads << endl;
//##########################################################################
cout << "\n=== Memory allocation ===" << endl;
vector<double> x(N), y(N);
cout << "Allocated memory for vectors x and y (" << N << " doubles each)" << endl;
//##########################################################################
cout << "\n=== Data initialization ===" << endl;
for (unsigned int i = 0; i < N; ++i)
{
x[i] = i + 1;
y[i] = 1.0 / x[i];
}
cout << "Vectors initialized: x[i] = i+1, y[i] = 1/x[i]" << endl;
//##########################################################################
cout << "\n=== Start Benchmarking inner product ===" << endl;
double tstart = omp_get_wtime();
double sk(0.0);
for (int i = 0; i < NLOOPS; ++i)
{
sk = scalar(x, y);
sk = scalar_trans(x, y);
}
double t1 = (omp_get_wtime() - tstart) / NLOOPS;
cout << "<x, y> = " << sk << endl;
if (static_cast<unsigned int>(sk) != N)
cout << "!! WRONG result !!" << endl;
cout << "Timing (average per loop) in sec: " << t1 << endl;
cout << "GFLOPS: " << 2.0 * N / t1 / 1024 / 1024 / 1024 << endl;
cout << "Memory throughput (GiByte/s): " << 2.0 * N / t1 / 1024 / 1024 / 1024 * sizeof(x[0]) << endl;
//##########################################################################
cout << "\n=== Testing reduction_vec (combining vectors across threads) ===" << endl;
cout << "Each thread initializes a vector of size 100; then vectors are combined." << endl;
auto vr = reduction_vec(100);
cout << "Resulting combined vector:" << endl;
cout << vr << endl;
cout << "\n=== Program finished ===" << endl;
return 0;
}