高性能计算：实验作业及代码

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <mpi.h> void generate_diamond_part(int size, int start_row, int end_row, char* buffer) { int half_size = size / 2; int line_idx, space_count, star_count, buffer_idx = 0; for (line_idx = start_row; line_idx < end_row; ++line_idx) { space_count = abs(half_size - line_idx); star_count = size - space_count * 2; memset(buffer + buffer_idx, ' ', space_count); buffer_idx += space_count; memset(buffer + buffer_idx, '#', star_count); buffer_idx += star_count; memset(buffer + buffer_idx, ' ', space_count); buffer_idx += space_count; buffer[buffer_idx++] = '\n'; } buffer[buffer_idx] = '\0'; } int main(int argc, char* argv[]) { int rank, size, i; int ARRAY_SIZE = 4001; // Make sure this is an odd number int line_length = ARRAY_SIZE + 1; // Including newline char* diamond_part; char* full_diamond = NULL; int* recv_counts; int* displacements; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &rank); MPI_Comm_size(MPI_COMM_WORLD, &size); double start_time = MPI_Wtime(); int lines_per_proc = ARRAY_SIZE / size; int remaining_lines = ARRAY_SIZE % size; int start = lines_per_proc * rank + ((rank < remaining_lines) ? rank : remaining_lines); int lines_this_proc = lines_per_proc + ((rank < remaining_lines) ? 1 : 0); int end = start + lines_this_proc; // Allocate buffer for local diamond part diamond_part = malloc(lines_this_proc * line_length * sizeof(char)); generate_diamond_part(ARRAY_SIZE, start, end, diamond_part); // Gather all parts of the diamond at the root process if (rank == 0) { // Only root process holds the entire diamond full_diamond = malloc(ARRAY_SIZE * line_length * sizeof(char)); recv_counts = malloc(size * sizeof(int)); displacements = malloc(size * sizeof(int)); for (i = 0; i < size; ++i) { int lines_proc = lines_per_proc + ((i < remaining_lines) ? 1 : 0); recv_counts[i] = lines_proc * line_length; displacements[i] = (i < remaining_lines) ? (i * (lines_per_proc + 1) * line_length) : (remaining_lines * (lines_per_proc + 1) * line_length + (i - remaining_lines) * lines_per_proc * line_length); } } MPI_Barrier(MPI_COMM_WORLD); // 同步所有进程 // Gather all parts of the diamond at the root process MPI_Gatherv(diamond_part, lines_this_proc * line_length, MPI_CHAR, full_diamond, recv_counts, displacements, MPI_CHAR, 0, MPI_COMM_WORLD); // 计时结束 MPI_Barrier(MPI_COMM_WORLD); // 同步所有进程 double end_time = MPI_Wtime(); // 打印结果 if (rank == 0) { // Root process prints the full diamond twice full_diamond[ARRAY_SIZE * line_length - 1] = '\0'; // Remove last newline printf("First diamond:\n%s\n", full_diamond); printf("Second diamond:\n%s\n", full_diamond); } // 打印运行时间 if (rank == 0) { printf("Runtime: %f seconds\n", end_time - start_time); } // Clean up resources free(diamond_part); if (rank == 0) { free(full_diamond); free(recv_counts); free(displacements); } MPI_Finalize(); return 0; }