task8

ex3/seq/skalar/main.cpp

@@ -0,0 +1,105 @@
+#include "mylib.h"
+
+#include <chrono>             // timing
+#include <cstdlib>            // atoi()
+#include <cstring>            // strncmp()
+#include <execution>          // policy
+#include <iostream>
+#include <numeric>            // transform_reduce
+#include <sstream>
+#include <vector>
+
+using namespace std;
+using namespace std::chrono;  // timing
+
+int main(int argc, char **argv)
+{
+    int const NLOOPS = 50;        // chose a value such that the benchmark runs at least 10 sec.
+    unsigned int N = 50000001;
+//##########################################################################
+//   Read Paramater from command line  (C++ style)
+    cout << "Checking command line parameters for: -n <number> " << endl;
+    for (int i = 1; i < argc; i++)
+    {
+        cout << " arg[" << i << "] = " << argv[i] << endl;
+        if (std::strncmp(argv[i], "-n", 2) == 0 && i + 1 < argc) // found "-n" followed by another parameter
+        {
+            N = static_cast<unsigned int>(atoi(argv[i + 1]));
+        }
+        else
+        {
+            cout << "Corect call: " << argv[0] << " -n  <number>\n";
+        }
+    }
+
+    cout << "\nN = " << N << endl;
+
+//##########################################################################
+//  Memory allocation
+    cout << "Memory allocation\n";
+
+    //double *x = new double [N];
+    //double *y = new double [N];
+    vector<double> x(N);
+    vector<double> y(N);
+    //alignas(16) double x[N], y[N];
+
+    cout.precision(2);
+    cout << 2.0 * N *sizeof(x[0]) / 1024 / 1024 / 1024 << " GiByte Memory allocated\n";
+    cout.precision(6);
+
+//##########################################################################
+//  Data initialization
+//  Special:  x_i = i+1;  y_i = 1/x_i  ==> <x,y> == N
+    for (unsigned int i = 0; i < N; ++i)
+    {
+        x[i] = i + 1;
+        y[i] = 1.0 / x[i];
+    }
+
+//##########################################################################
+    cout << "\nStart Benchmarking\n";
+
+    auto tstart = system_clock::now();       // start timer
+
+// Do calculation
+    double sk(0.0);
+
+    for (int i = 0; i < NLOOPS; ++i)
+    {
+        //sk = scalar(N, x, y);
+        sk += scalar_unroll(N, x.data(), y.data());
+        //sk += transform_reduce(std::execution::par_unseq,cbegin(x),cend(x),cbegin(y),0.0);
+//      sk = norm(N,x);
+    }
+
+    auto tend = system_clock::now();         // end timer
+    auto duration = duration_cast<microseconds>(tend - tstart);
+    auto t1 = static_cast<double>(duration.count()) / 1e6 ;   // t1 in seconds
+    t1 /= NLOOPS;           // divide by number of function calls
+
+//##########################################################################
+// Check the correct result
+    sk /= NLOOPS;
+    cout << "\n <x,y> = " << sk << endl;
+    if (static_cast<unsigned int>(sk) != N)
+    {
+        cout << "  !!   W R O N G  result   !!\n";
+    }
+    cout << endl;
+
+//##########################################################################
+// Timings  and Performance
+    cout << endl;
+    cout.precision(2);
+    cout << "Timing in sec. : " << t1 << endl;
+    cout << "GFLOPS         : " << 2.0 * N / t1 / 1024 / 1024 / 1024 << endl;
+    cout << "GiByte/s        : " << 2.0 * N / t1 / 1024 / 1024 / 1024 * sizeof(x[0]) << endl;
+
+//##########################################################################
+//  Free allocated memory
+    //delete [] y;
+    //delete [] x;
+
+    return 0;
+}