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44 lines
1.5 KiB
C++
44 lines
1.5 KiB
C++
#include <mpi.h>
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#include <iostream>
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#include <cstdlib>
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#include <ctime>
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/*
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MPI_Bcast(
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void* buffer, //the element to send
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int count, //number of element to send
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MPI_Datatype datatype, //type of element
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int root, //rank of the process that have to sand value to others
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MPI_Comm comm //communicator
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)
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*/
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int main(int argc, char* argv[])
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{
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MPI_Init(&argc, &argv); //Initialize the MPI environment //TODO perche qui non (NULL, NULL) ??
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int world_size;
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MPI_Comm_size(MPI_COMM_WORLD, &world_size); //Get the number of processes
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int recvbuf[4*world_size];
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int world_rank;
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MPI_Comm_rank(MPI_COMM_WORLD, &world_rank); //Get the number of process
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long long offset;
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std::srand(std::time(0) + world_rank);
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offset = std::rand() % 100; //Give a random value to initialize element of each process
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std::cout << "Process (rank " << world_rank+1 << "/" << world_size << ") recived: " << offset << std::endl;
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MPI_Barrier(MPI_COMM_WORLD); //Used to not mess with the prints
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//MPI_Bcast(buffer, count, datatype, root, comm)
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MPI_Bcast(&offset, 1, MPI_LONG_LONG, 0, MPI_COMM_WORLD);
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/*Posso utilizzare BroadCast anche con un solo nodo, invia a se stesso. Non posso usilizzare come root un nodo con rank maggiore della size.*/
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std::cout <<"Process (rank " << world_rank+1 << "/" << world_size << ") recived: " << offset << std::endl;
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MPI_Finalize(); //Clean up the MPI environment
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return 0;
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} |