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68 | #include <iomanip>
#include <iostream>
#include <mpi.h>
#include <cstdlib>
#include <ctime>
const char* compare(double num, double ref)
{
if ( num < ref )
return "less than";
if ( num > ref )
return "greater than";
return "equals to";
}
int main(int argc, char* argv[])
{
MPI_Init(&argc, &argv);
int my_rank = -1;
int process_count = -1;
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
MPI_Comm_size(MPI_COMM_WORLD, &process_count);
char hostname[MPI_MAX_PROCESSOR_NAME];
int hostname_length = -1;
MPI_Get_processor_name(hostname, &hostname_length);
srand( my_rank + time(nullptr) + clock() );
int my_lucky_number = rand() % 100;
int global_min = -1;
int global_sum = -1;
int global_max = -1;
MPI_Allreduce(&my_lucky_number, &global_min, /*count*/ 1, MPI_INT, MPI_MIN, MPI_COMM_WORLD);
MPI_Allreduce(&my_lucky_number, &global_sum, /*count*/ 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
MPI_Allreduce(&my_lucky_number, &global_max, /*count*/ 1, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
char ready = 'Y';
if ( my_rank != 0 )
MPI_Recv(&ready, /*capacity*/ 1, MPI_CHAR, /*source*/ my_rank - 1, /*tag*/ 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
double average = static_cast<double>(global_sum) / process_count;
std::cout << std::setfill('0') << std::fixed << std::setprecision(2);
if ( my_lucky_number == global_min )
std::cout << "Process " << my_rank << ": my lucky number (" << std::setw(2)
<< my_lucky_number << ") is the minimum ("<< std::setw(2) << global_min << ")\n";
std::cout << "Process " << my_rank << ": my lucky number (" << std::setw(2)
<< my_lucky_number << ") is " << compare(my_lucky_number, average)
<< " the average (" << std::setw(2) << average << ")\n";
if ( my_lucky_number == global_max )
std::cout << "Process " << my_rank << ": my lucky number (" << std::setw(2)
<< my_lucky_number << ") is the maximum (" << std::setw(2) << global_max << ")\n";
if ( my_rank < process_count - 1 )
MPI_Send(&ready, /*count*/ 1, MPI_CHAR, /*dest*/ my_rank + 1, /*tag*/ 0, MPI_COMM_WORLD);
MPI_Finalize();
}
|