Solutions

sheet1/G/main.cpp

@@ -0,0 +1,109 @@
+#include "mylib.h"
+#include <iostream>
+#include <cassert>
+#include <vector>
+using namespace std;
+int main()
+{
+
+    //b)
+    DenseMatrix const M(5,3); // Dense matrix, also initialized
+    vector<double> const u{{1,2,3}};
+    vector<double> f1 = M.Mult(u);
+    vector<double> const v{{-1,2,-3,4,-5}};
+    vector<double> f2 = M.MultT(v);
+
+    for(unsigned int i = 0; i < f1.size(); i++)
+    {
+        cout << f1.at(i) << " ";
+    }
+    cout << endl;
+    for(unsigned int i = 0; i < f2.size(); i++)
+    {
+        cout << f2.at(i) << " ";
+    }
+    cout << endl;
+
+
+    //c)
+    int n=5000;
+    DenseMatrix const A(n,n);
+    vector<double> w = {};
+    for(int i = -n/2; i < n/2; i++)
+    {
+        w.push_back(i);
+    } 
+
+
+    int const NLOOPS=100;
+
+    double t1 = clock(); // start timer
+    vector<double> f3 = A.Mult(w);
+    for (int k=1; k<NLOOPS; ++k)
+    {
+        f3 = A.Mult(w);
+    }
+    t1 = (clock()-t1)/CLOCKS_PER_SEC/NLOOPS;
+    cout << "Time for Mult per it: " << t1 << endl;
+
+    double t2 = clock(); // start timer
+    vector<double> f4 = A.MultT(w);
+    for (int k=1; k<NLOOPS; ++k)
+    {
+        f4 = A.MultT(w);
+    }
+    t2 = (clock()-t2)/CLOCKS_PER_SEC/NLOOPS;
+    cout << "Time for MultT per it: " << t2 << endl; 
+    //slower because consecutive calls to data vector of Matrix are more apart (+m) due to column wise access (non contiguous memory)
+
+    double maxDiff = 0.0;
+    for (size_t i = 0; i < f3.size(); ++i) {
+        double diff = abs(f3[i] - f4[i]);
+        if (diff > maxDiff) {
+            maxDiff = diff;
+        }
+    }
+    cout << "difference f3 and f4: " << maxDiff << endl;
+
+
+    //d)
+    cout << "-----------------DYADIC------------------" <<endl;
+    vector<double> x = {};
+    for(int k=0; k < n; k++)
+    {
+        x.push_back(f(k, n));
+    }
+    Dyadic const D(x,x);
+
+    double t3 = clock(); // start timer
+    vector<double> f5 = D.Mult(w);
+    for (int k=1; k<NLOOPS; ++k)
+    {
+        f5 = D.Mult(w);
+    }
+    t3 = (clock()-t3)/CLOCKS_PER_SEC/NLOOPS;
+    cout << "Time for Mult per it: " << t3 << endl;
+
+    double t4 = clock(); // start timer
+    vector<double> f6 = D.MultT(w);
+    for (int k=1; k<NLOOPS; ++k)
+    {
+        f6 = D.MultT(w);
+    }
+    t4 = (clock()-t4)/CLOCKS_PER_SEC/NLOOPS;
+    cout << "Time for MultT per it: " << t4 << endl; 
+    //slower because consecutive calls to data vector of Matrix are more apart (+m) due to column wise access (non contiguous memory)
+
+    double maxDiff2 = 0.0;
+    for (size_t i = 0; i < f5.size(); ++i) {
+        double diff = abs(f5[i] - f6[i]);
+        if (diff > maxDiff2) {
+            maxDiff2 = diff;
+        }
+    }
+    cout << "difference f5 and f6: " << maxDiff2 << endl;
+
+
+    
+    return 0;
+}