ex5 task5

ex5/code/task_1/demo_skalar/mylib.cpp

@@ -0,0 +1,84 @@
+#include "mylib.h"
+#include <cassert>       // assert()
+#include <cmath>
+#include <iostream>
+#include <functional>    // multiplies<>{}
+#include <list>
+#include <numeric>       // iota()
+#ifdef _OPENMP
+#include <omp.h>
+#endif
+#include <vector>
+using namespace std;
+
+double scalar(vector<double> const &x, vector<double> const &y)
+{
+    assert(x.size() == y.size()); // switch off via compile flag: -DNDEBUG
+    size_t const N = x.size();
+    double sum = 0.0;
+#pragma omp parallel for default(none) shared(x,y,N) reduction(+:sum) schedule(static)
+    for (size_t i = 0; i < N; ++i)
+    {
+        sum += x[i] * y[i];
+        //sum += exp(x[i])*log(y[i]);
+    }
+    return sum;
+}
+
+double scalar2(vector<double> const &x, vector<double> const &y)
+{
+    assert(x.size() == y.size());
+    size_t const N = x.size();
+    double sum = 0.0;
+
+    #pragma omp parallel shared(x,y,N,sum)
+    {
+        double local_sum = 0.0;
+
+        int const th_id  = omp_get_thread_num();
+        int const nthrds = omp_get_num_threads();
+
+        for (size_t i = th_id; i < N; i += nthrds) {
+            local_sum += x[i] * y[i];
+        }
+
+        #pragma omp atomic
+        sum += local_sum;
+    }
+    return sum;
+}
+
+
+vector<int> reduction_vec(int n)
+{ 
+    vector<int> vec(n);
+#pragma omp parallel default(none) shared(cout) reduction(VecAdd:vec)
+    {
+        #pragma omp barrier
+        #pragma omp critical
+        cout << omp_get_thread_num() << " : " << vec.size() << endl;
+        #pragma omp barrier
+        iota( vec.begin(),vec.end(), omp_get_thread_num() );
+        #pragma omp barrier
+        #pragma omp critical
+        cout << vec << endl;
+    }
+    return vec;
+}
+
+vector<int> reduction_vec_append(int n)
+{ 
+    vector<int> vec;
+#pragma omp parallel default(none) shared(cout,n) reduction(VecAppend:vec)
+    {
+        vector<int> local(n);
+        #pragma omp barrier
+        #pragma omp critical
+        cout << omp_get_thread_num() << " : " << local.size() << endl;
+        #pragma omp barrier
+        iota( local.begin(),local.end(), omp_get_thread_num() );
+        #pragma omp critical
+        vec.insert(vec.end(), local.begin(), local.end());
+    }
+    return vec;
+}