使用c语言编写使用openmp算法的PageRank的完整代码，其中数据集来自于文件

好的，以下是使用c语言编写使用openmp算法的PageRank的完整代码，其中数据集来自于文件。

#include <stdio.h>
#include <stdlib.h>
#include <omp.h>

#define MAX_PAGES 1000
#define EPSILON 0.0001

int main(int argc, char *argv[]) {
    int num_pages, num_links, max_iterations;
    double damping_factor, page_rank[MAX_PAGES], new_page_rank[MAX_PAGES];
    int link_from[MAX_PAGES], link_to[MAX_PAGES], link_count[MAX_PAGES];
    FILE *input_file = NULL, *output_file = NULL;
    int i, j, k, iter;

    // Open input file
    input_file = fopen("input.txt", "r");
    if (input_file == NULL) {
        printf("Error: Unable to open input file!\n");
        return 1;
    }

    // Read input parameters
    fscanf(input_file, "%d %d %lf %d", &num_pages, &num_links, &damping_factor, &max_iterations);
    if (num_pages > MAX_PAGES) {
        printf("Error: Number of pages exceeds maximum limit!\n");
        return 1;
    }

    // Initialize arrays
    for (i = 0; i < num_pages; i++) {
        page_rank[i] = 1.0 / num_pages;
        new_page_rank[i] = 0.0;
        link_count[i] = 0;
    }

    // Read link data
    for (i = 0; i < num_links; i++) {
        fscanf(input_file, "%d %d", &link_from[i], &link_to[i]);
        link_count[link_from[i]]++;
    }

    // Close input file
    fclose(input_file);

    // Perform PageRank iterations
    for (iter = 0; iter < max_iterations; iter++) {
        #pragma omp parallel for private(j, k) shared(page_rank, new_page_rank)
        for (i = 0; i < num_pages; i++) {
            new_page_rank[i] = (1.0 - damping_factor) / num_pages;

            for (j = 0; j < num_links; j++) {
                if (link_to[j] == i) {
                    k = link_from[j];
                    new_page_rank[i] += damping_factor * page_rank[k] / link_count[k];
                }
            }
        }

        // Check for convergence
        double diff = 0.0;
        for (i = 0; i < num_pages; i++) {
            diff += fabs(new_page_rank[i] - page_rank[i]);
        }

        if (diff < EPSILON) {
            printf("Converged after %d iterations.\n", iter + 1);
            break;
        }

        // Swap page rank arrays
        double *temp = page_rank;
        page_rank = new_page_rank;
        new_page_rank = temp;
    }

    // Open output file
    output_file = fopen("output.txt", "w");
    if (output_file == NULL) {
        printf("Error: Unable to open output file!\n");
        return 1;
    }

    // Write page rank data
    for (i = 0; i < num_pages; i++) {
        fprintf(output_file, "%.6f\n", page_rank[i]);
    }

    // Close output file
    fclose(output_file);

    return 0;
}

该代码使用了OpenMP的并行计算技术，将每个迭代过程分解为多个并发执行的线程，从而加快计算速度。在迭代过程中，将每个网页的PageRank值存储在page_rank数组中，新的PageRank值存储在new_page_rank数组中，两者交替使用以实现迭代更新。在每个迭代过程中，使用#pragma omp parallel for指令将循环体并行化。