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  1. #include <iostream>
  2. #include <cmath>
  3. #include <mpi.h>
  4. #include <fstream>
  5. #include <vector>
  6. #include <cstdlib> // for system function
  7.  
  8. using namespace std;
  9.  
  10. void writeDataToFile(const string& filename, int x, long double y) {
  11.     ofstream file(filename, ios::app);
  12.     if (file.is_open()) {
  13.         printf("size and time: %f",y);
  14.         file << x << " " << y<<" \n" << endl;
  15.         file.close();
  16.     }
  17.     else {
  18.         cerr << "Unable to open file for writing." <<endl;
  19.     }
  20. }
  21.  
  22. double f(double x) {
  23.     // Функция, которую мы интегрируем
  24.     return cos(6*x)*sin(5*x) + 4;
  25. }
  26.  
  27. double rectangle_integration(double a, double b, int n) {
  28.  
  29. double simpson(double a, double b, int n, double h) {
  30.     double sum = f(a) + f(b);
  31.  
  32.     for (int i = 1; i < n; i += 2) {
  33.         double x = a + i * h;
  34.         sum += 4 * f(x);
  35.     }
  36.  
  37.     for (int i = 2; i < n - 1; i += 2) {
  38.         double x = a + i * h;
  39.         sum += 2 * f(x);
  40.     }
  41.  
  42.     return sum * h / 3.0;
  43. }
  44.  
  45.  
  46.  
  47. }
  48.  
  49. int main(int argc, char** argv) {
  50.  
  51.     const double a = 0.0;
  52.     const double b = 1;
  53.     const int n = 1000000; 
  54.  
  55.     int rank, size=10;
  56.     long double min_start = 1000000, max_end = 0, start, end, local_result, total_result;
  57.  
  58.     MPI_Init(&argc, &argv);
  59.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  60.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  61.     MPI_Barrier(MPI_COMM_WORLD);
  62.  
  63.     start = MPI_Wtime();
  64.  
  65.     cout << "Process " << rank << " of " << size << " is running." << endl;
  66.  
  67.  
  68.     // Вычисляем локальный результат для каждого процесса
  69.     int local_n = n / size;
  70.     double local_a = a + rank * (b - a) / size;
  71.     double local_b = local_a + (b - a) / size;
  72.     double h = (b - a) / n;
  73.     //local_result = rectangle_integration(local_a, local_b, local_n);
  74.     //local_result = simpson(local_a, local_b, local_n, h);
  75.     local_result = trapezoidal(local_a, local_b, local_n, h);
  76.  
  77.     MPI_Reduce(&local_result, &total_result, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
  78.     MPI_Barrier(MPI_COMM_WORLD);
  79.     end = MPI_Wtime();
  80.  
  81.  
  82.     if (rank == 0) {
  83.         cout << "Total result: " << total_result << endl;
  84.     }
  85.  
  86.     int numproc;
  87.  
  88.     numproc = size;
  89.  
  90.  
  91.  
  92.     // Find max time
  93.     if (min_start > start) {
  94.         min_start = start;
  95.     }
  96.  
  97.     if (max_end < end) {
  98.         max_end = end;
  99.     }
  100.  
  101.     if (rank == 0) {
  102.         printf("Time taken to process: %f", (max_end - min_start));
  103.     }
  104.     if (rank == 0) {
  105.         writeDataToFile("data.txt", numproc, (max_end - min_start));
  106.     }
  107.     MPI_Finalize();
  108.  
  109.  
  110.  
  111.  
  112.     return 0;
  113. }
  114.  
Success #stdin #stdout #stderr 0.27s 40768KB
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Standard input is empty
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Standard output is empty
stderr
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Error: unexpected symbol in "using namespace"
Execution halted
https://ideone.com/tfzpIr
language:
R (R 3.5.2)
created:
14 days ago
visibility:
public

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