90 lines
3.3 KiB
C++
90 lines
3.3 KiB
C++
#include <iostream>
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#include <vector>
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#include <mpi.h>
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#include <unistd.h> // Required for gethostname() and getpid()
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#include <cstdlib> // Required for getenv()
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#include <string> // Required for std::string
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int main(int argc, char** argv) {
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MPI_Init(&argc, &argv);
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int world_size;
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MPI_Comm_size(MPI_COMM_WORLD, &world_size);
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int world_rank;
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MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
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char container_id[256];
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gethostname(container_id, sizeof(container_id));
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const char* friendly_name = getenv("FRIENDLY_NAME");
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if (friendly_name == nullptr) { friendly_name = "unknown"; }
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pid_t pid = getpid();
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int num_workers = world_size - 1;
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if (world_rank == 0) {
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// --- MASTER PROCESS ---
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// Q2. Master has an array {2,3,4,5}.
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int data[] = {2, 3, 4, 5};
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int data_count = sizeof(data) / sizeof(int);
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if (data_count != num_workers) {
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std::cerr << "Error: This task requires exactly 4 workers (" << num_workers
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<< " found). Please run with -np 5." << std::endl;
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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std::cout << "Master on " << friendly_name << " (ID: " << container_id << ", PID: " << pid
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<< ", rank: 0): distributing array {2,3,4,5} to workers." << std::endl;
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for (int i = 0; i < num_workers; ++i) {
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MPI_Send(&data[i], 1, MPI_INT, i + 1, 0, MPI_COMM_WORLD);
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}
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std::vector<int> results(num_workers);
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for (int i = 0; i < num_workers; ++i) {
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int received_result;
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MPI_Recv(&received_result, 1, MPI_INT, i + 1, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
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results[i] = received_result;
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}
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std::cout << "Master on " << friendly_name << " (ID: " << container_id << ", PID: " << pid
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<< ", rank: 0): gathered results {";
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for (int i = 0; i < results.size(); ++i) {
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std::cout << results[i] << (i == results.size() - 1 ? "" : ",");
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}
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std::cout << "}" << std::endl;
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} else {
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// --- WORKER PROCESSES ---
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int received_number;
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MPI_Recv(&received_number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
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int computed_result = 0;
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std::string operation_string;
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// Q2. Different workers perform different computations based on their rank.
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if (world_rank == 1) {
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computed_result = received_number * received_number;
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operation_string = "squared ->";
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} else if (world_rank == 2) {
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computed_result = received_number * received_number * received_number;
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operation_string = "cubed ->";
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} else if (world_rank == 3) {
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computed_result = received_number * 2;
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operation_string = "doubled ->";
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} else if (world_rank == 4) {
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computed_result = received_number - 1;
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operation_string = "subtracted 1 ->";
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}
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std::cout << "Worker on " << friendly_name << " (ID: " << container_id << ", PID: " << pid
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<< ", rank: " << world_rank << "): received " << received_number
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<< ", " << operation_string << " " << computed_result << std::endl;
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MPI_Send(&computed_result, 1, MPI_INT, 0, 0, MPI_COMM_WORLD);
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}
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MPI_Finalize();
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return 0;
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} |