162 lines
4.0 KiB
C
162 lines
4.0 KiB
C
#include <mpi.h>
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#include <stdio.h>
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#include <stdlib.h>
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int compare(const void *a, const void *b)
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{
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return (*(int *)a - *(int *)b);
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}
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void merge(int *a, int *b, int *merged, int size)
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{
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int i = 0, j = 0, k = 0;
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while (i < size && j < size)
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{
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if (a[i] < b[j])
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{
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merged[k++] = a[i++];
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}
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else
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{
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merged[k++] = b[j++];
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}
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}
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while (i < size)
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merged[k++] = a[i++];
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while (j < size)
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merged[k++] = b[j++];
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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);
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int my_rank, comm_sz;
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MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
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MPI_Comm_size(MPI_COMM_WORLD, &comm_sz);
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const int LOCAL_SIZE = 1250; // 共排序10000个元素，用8个进程，每个进程1250个元素
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int *full_data = NULL;
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if (my_rank == 0)
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{
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FILE *fp = fopen("input.txt", "r");
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if (fp == NULL)
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{
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fprintf(stderr, "Failed to open input file\n");
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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int total_size = comm_sz * LOCAL_SIZE;
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full_data = malloc(total_size * sizeof(int));
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for (int i = 0; i < total_size; i++)
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{
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if (fscanf(fp, "%d", &full_data[i]) != 1)
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{
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fprintf(stderr, "Invalid input format\n");
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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}
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fclose(fp);
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}
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int *local_data = malloc(LOCAL_SIZE * sizeof(int));
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if (local_data == NULL)
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{
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fprintf(stderr, "Memory allocation failed!\n");
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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MPI_Scatter(full_data, LOCAL_SIZE, MPI_INT,
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local_data, LOCAL_SIZE, MPI_INT,
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0, MPI_COMM_WORLD);
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// 本地排序
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qsort(local_data, LOCAL_SIZE, sizeof(int), compare);
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// 奇偶阶段排序
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for (int phase = 0; phase < comm_sz; phase++)
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{
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int partner;
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// 计算partner
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if (phase % 2 == 0)
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{
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partner = my_rank + 1;
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}
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else
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{
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partner = my_rank - 1;
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}
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// 检查partner是否有效
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if (partner < 0 || partner >= comm_sz)
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{
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continue;
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}
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// 准备发送和接收缓冲区
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int *received_data = malloc(LOCAL_SIZE * sizeof(int));
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int *merged_data = malloc(2 * LOCAL_SIZE * sizeof(int));
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// 使用阻塞式通信交换数据
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MPI_Sendrecv(local_data, LOCAL_SIZE, MPI_INT, partner, 0,
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received_data, LOCAL_SIZE, MPI_INT, partner, 0,
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MPI_COMM_WORLD, MPI_STATUS_IGNORE);
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// 合并两个有序数组
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merge(local_data, received_data, merged_data, LOCAL_SIZE);
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// 保留前一半或后一半
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if (my_rank < partner)
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{
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// 保留较小的一半
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for (int i = 0; i < LOCAL_SIZE; i++)
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{
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local_data[i] = merged_data[i];
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}
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}
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else
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{
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// 保留较大的一半
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for (int i = 0; i < LOCAL_SIZE; i++)
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{
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local_data[i] = merged_data[LOCAL_SIZE + i];
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}
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}
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free(received_data);
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free(merged_data);
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}
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// 排序完成后收集结果到0号进程
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int *global_data = NULL;
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if (my_rank == 0)
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{
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global_data = malloc(comm_sz * LOCAL_SIZE * sizeof(int));
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}
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MPI_Gather(local_data, LOCAL_SIZE, MPI_INT,
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global_data, LOCAL_SIZE, MPI_INT,
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0, MPI_COMM_WORLD);
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if (my_rank == 0)
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{
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FILE *fout = fopen("output.txt", "w");
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if (fout == NULL)
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{
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fprintf(stderr, "Failed to open output file\n");
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MPI_Abort(MPI_COMM_WORLD, 1);
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}
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for (int i = 0; i < comm_sz * LOCAL_SIZE; i++)
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{
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fprintf(fout, "%d ", global_data[i]);
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}
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fprintf(fout, "\n");
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fclose(fout);
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}
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free(local_data);
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free(full_data);
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free(global_data);
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MPI_Finalize();
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return 0;
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} |