LisaPizzoExercises/Sheet5/mainEx2.cpp
2025-12-02 09:37:02 +01:00

86 lines
2.5 KiB
C++

//HOW TO RUN IT ON MY TERMINAL (MAC)
//export PATH="/opt/homebrew/opt/llvm/bin:$PATH"
//export CPPFLAGS="-I/opt/homebrew/opt/libomp/include"
//export LDFLAGS="-L/opt/homebrew/opt/libomp/lib"
//clang++ -std=c++17 -O2 -Xpreprocessor -fopenmp $CPPFLAGS mainEx2.cpp $LDFLAGS -lomp -o Ex2
//./Ex2
#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <omp.h> //for parallelization functions
using namespace std;
// compute arithmetic, geometric, harmonic means (safe geometric mean)
void computeMeansVector(const vector<int> &v, double &arith, double &geom, double &harm) {
int n = v.size();
double sum = 0.0, logSum = 0.0, recSum = 0.0;
for (int x : v) {
sum += x;
logSum += log(x); // accumulate logarithms instead of multiplying
recSum += 1.0 / x;
}
arith = sum / n;
geom = exp(logSum / n); // geometric mean using exponent of average log
harm = n / recSum;
}
// compute standard deviation
double computeStdDev(const vector<int> &v, double mean) {
double sumSq = 0.0;
for (int x : v) {
sumSq += (x - mean) * (x - mean);
}
return sqrt(sumSq / v.size());
}
int main() {
vector<int> v;
ifstream fin("data_1.txt"); //opens data for reading
int x;
while (fin >> x) {
v.push_back(x);
}
double t_start = omp_get_wtime();
// OpenMP threads check
int nthreads = 0;
#pragma omp parallel
{
int th_id = omp_get_thread_num();
#pragma omp critical
{
cout << "Hello from thread " << th_id << endl;
}
#pragma omp master
nthreads = omp_get_num_threads();
}
cout << "Total OpenMP threads used: " << nthreads << endl;
int minVal = *min_element(v.begin(), v.end());
int maxVal = *max_element(v.begin(), v.end());
double arith, geom, harm;
computeMeansVector(v, arith, geom, harm);
double stddev = computeStdDev(v, arith);
ofstream fout("out_1.txt");
fout << "Min: " << minVal << "\nMax: " << maxVal
<< "\nArithmetic mean: " << arith
<< "\nGeometric mean: " << geom
<< "\nHarmonic mean: " << harm
<< "\nStandard deviation: " << stddev << "\n";
cout << "Min: " << minVal << "\nMax: " << maxVal
<< "\nArithmetic mean: " << arith
<< "\nGeometric mean: " << geom
<< "\nHarmonic mean: " << harm
<< "\nStandard deviation: " << stddev << endl;
cout << "Elapsed time (s): " << omp_get_wtime() - t_start << endl;
}