Main file - Exercise 2

Sheet5/mainEx2.cpp

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+//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;
+}