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  1. #include<iostream>
  2. #include<random>
  3. #include<time.h>
  4. #include<vector>
  5. #include<cmath>
  6. #include<cstdio>
  7. using namespace std;
  8.  
  9. float time(int n){
  10. vector<vector<int >> A(n, vector<int>(n,0));
  11. vector<int> v(n,0);
  12. vector<int> m(n,0);
  13.  
  14. for(int i=0; i<n; i++){
  15.   for(int j=0; j<n; j++){
  16.     A[i][j]=rand();
  17.     }
  18.   v[i]=rand();
  19.   }
  20.  
  21. clock_t t;
  22. t= clock();
  23.  
  24. for(int i=0; i<n; i++){
  25.   for(int j=0; j<n; j++){
  26.     m[i]+= A[i][j]*v[j];
  27.     }
  28.   }
  29. t= clock()-t;
  30. //printf("operations took %ld clicks (%f seconds).\n",t,((float)t)/CLOCKS_PER_SEC);
  31. return (((float)t)/CLOCKS_PER_SEC);
  32. }
  33.  
  34. vector<float> t(5,0);
  35. int main(){
  36. for(int i=256; i<5000; i=i*2){
  37.   int k= i/256;
  38.   int j= log2(k);
  39.   t[j] = time(i);
  40. }
  41. FILE* gp = popen("gnuplot -persistent", "w");
  42.  
  43.     fprintf(gp, "set title 'operational time vs n'\n");
  44.     fprintf(gp, "set xlabel 'order of matrix- n'\n");
  45.     fprintf(gp, "set ylabel 'time taken(s)'\n");
  46.     fprintf(gp, "plot '-' with lines title 'time(s)'\n");
  47.  
  48.     for (double x = 0; x < 5; x ++) {
  49.         fprintf(gp, "%f %f\n", (256*pow(2,x)), t[x]);
  50.     }
  51.  
  52.     fprintf(gp, "e\n");   // end of data
  53.     fflush(gp);
  54.     pclose(gp);
  55.     return 0;
  56.  
  57. }
Success #stdin #stdout #stderr 0.32s 68896KB
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Standard input is empty
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Standard output is empty
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sh: 1: gnuplot: not found
https://ideone.com/DMBBxs
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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