ex5

ex5/code/task_3.cpp

@@ -0,0 +1,73 @@
+#include "task_3.h"
+#include "mayer_primes.h"
+#include "timing.h"
+
+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <omp.h>
+#include <vector>
+using namespace std;
+
+
+int single_goldbach_par(int k) {
+    const vector<int> primes = get_primes(k);
+    int count = 0;
+
+    #pragma omp parallel for reduction(+:count)
+    for (size_t i = 0; i < primes.size(); i++) {
+        for (size_t j = i; j < primes.size(); j++) {
+            if (primes[i] + primes[j] == k) {
+                count++;
+            }
+        }
+    }
+
+    return count;
+}
+
+
+vector<int> count_goldbach_par(int n) {
+    const vector<int> primes = get_primes(n);
+    vector<int> counts(n+1);
+
+    #pragma omp parallel reduction(VecAdd:counts)
+    // #pragma omp parallel
+    {
+        vector<int> local_counts(n+1, 0);
+
+            #pragma omp for
+        for (size_t i = 1; i < primes.size(); i++) {
+            for (size_t j = i; j < primes.size(); j++) {
+                int sum = primes[i] + primes[j];
+                if (sum <= n) {
+                    local_counts[sum]++;
+                }
+            }
+        }
+
+        counts += local_counts;
+        // #pragma omp critical
+        // {
+        //     for(int k=0; k<n+1; k++){
+        //     counts[k] += local_counts[k];
+        //     }
+        // }
+    }
+    return counts;
+}
+
+
+void print_decomps(int k) {
+    const vector<int> primes = get_primes(k);
+    cout << "\nDecompositions for k = " << k << ": ";
+
+    for (size_t i = 0; i < primes.size(); i++) {
+        for (size_t j = i; j < primes.size(); j++) {
+            if (primes[i] + primes[j] == k) {
+                cout << primes[i] << " + " << primes[j] << ", ";
+            }
+        }
+    }
+    cout << endl;
+}