fork download
copy 
  1. #include <iostream>
  2. #include <fstream>
  3. #include <vector>
  4. #include <mpi.h>
  5.  
  6. // #define _NO_CXX11_AT_QUICK_EXIT
  7. // #include <cstdlib>
  8.  
  9. using namespace std;
  10.  
  11. // Function to read a large number from a file into a vector of digits
  12. void read_number(const string &filename, vector<int> &digits) {
  13.     ifstream file(filename);
  14.     int num_digits;
  15.     file >> num_digits;  // Read the number of digits
  16.  
  17.     digits.resize(num_digits);
  18.     for (int i = 0; i < num_digits; ++i) {
  19.         file >> digits[i];
  20.     }
  21. }
  22.  
  23. // Function to write the result to a file
  24. void write_result(const string &filename, const vector<int> &result) {
  25.     ofstream file(filename);
  26.     file << result.size() << endl;  // Write the number of digits
  27.     for (int digit : result) {
  28.         file << digit << " ";
  29.     }
  30.     file << endl;
  31. }
  32.  
  33. int main(int argc, char* argv[]) {
  34.     MPI_Init(&argc, &argv);
  35.  
  36.     int rank, size;
  37.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  38.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  39.  
  40.     vector<int> num1_digits, num2_digits, result_digits;
  41.     vector<int> local_num1, local_num2, local_result;
  42.  
  43.     if (rank == 0) {
  44.         // Process 0 reads the numbers from files
  45.         read_number("Numar1.txt", num1_digits);
  46.         read_number("Numar2.txt", num2_digits);
  47.  
  48.         // Ensure both numbers have the same length by padding with zeros if necessary
  49.         int max_size = max(num1_digits.size(), num2_digits.size());
  50.         num1_digits.resize(max_size, 0);
  51.         num2_digits.resize(max_size, 0);
  52.  
  53.         result_digits.resize(max_size + 1, 0);  // Result can be one digit larger
  54.     }
  55.  
  56.     // Scatter the digits across processes
  57.     MPI_Scatter(num1_digits.data(), num1_digits.size() / size, MPI_INT,
  58.                 local_num1.data(), num1_digits.size() / size, MPI_INT, 0, MPI_COMM_WORLD);
  59.     MPI_Scatter(num2_digits.data(), num2_digits.size() / size, MPI_INT,
  60.                 local_num2.data(), num2_digits.size() / size, MPI_INT, 0, MPI_COMM_WORLD);
  61.  
  62.     // Perform local addition
  63.     int carry = 0;
  64.     for (int i = 0; i < local_num1.size(); ++i) {
  65.         int sum = local_num1[i] + local_num2[i] + carry;
  66.         local_result.push_back(sum % 10);  // Store the last digit
  67.         carry = sum / 10;  // Carry for the next addition
  68.     }
  69.  
  70.     // Gather results back to process 0
  71.     MPI_Gather(local_result.data(), local_result.size(), MPI_INT,
  72.                result_digits.data(), local_result.size(), MPI_INT, 0, MPI_COMM_WORLD);
  73.  
  74.     // Process 0 writes the result to the file
  75.     if (rank == 0) {
  76.         write_result("Numar3.txt", result_digits);
  77.     }
  78.  
  79.     MPI_Finalize();
  80.     return 0;
  81. }
  82.  
Success #stdin #stdout #stderr 0.33s 40312KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Standard output is empty
stderr
copy 
Error: unexpected '/' in "/"
Execution halted
https://ideone.com/KNTAvz
language:
R (R 3.5.2)
created:
10 hours ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!