diff options
Diffstat (limited to 'src/shortest/shortest_avg_max_hist.c')
| -rw-r--r-- | src/shortest/shortest_avg_max_hist.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/src/shortest/shortest_avg_max_hist.c b/src/shortest/shortest_avg_max_hist.c new file mode 100644 index 0000000..287c8a6 --- /dev/null +++ b/src/shortest/shortest_avg_max_hist.c @@ -0,0 +1,223 @@ +/** + * This program is free software: you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see + * <http://www.gnu.org/licenses/>. + * + * (c) Vincenzo Nicosia 2009-2017 -- <v.nicosia@qmul.ac.uk> + * + * This file is part of NetBunch, a package for complex network + * analysis and modelling. For more information please visit: + * + * http://www.complex-networks.net/ + * + * If you use this software, please add a reference to + * + * V. Latora, V. Nicosia, G. Russo + * "Complex Networks: Principles, Methods and Applications" + * Cambridge University Press (2017) + * ISBN: 9781107103184 + * + *********************************************************************** + * + * This program computes the distance from a given node to all the + * other nodes of an undirected graph, using the Breadth-First Search + * algorithm. + * + * + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "utils.h" + + +void usage(char *argv[]){ + printf("********************************************************************\n" + "** **\n" + "** -*- shortest_avg_max_hist -*- **\n" + "** **\n" + "** Compute the distance from the given 'node' to all the other **\n" + "** nodes of an undirected graph. The first parameter 'graph_in' **\n" + "** is the name of the file containing the edge list of the **\n" + "** graph. The second parameter 'node' is the label of the node **\n" + "** for which we want to compute the distances to all the other **\n" + "** nodes. **\n" + "** **\n" + "** If 'graph_in' is equal to '-' (dash), read the edge list **\n" + "** from standard input (STDIN) **\n" + "** **\n" + "** The program prints on output a row containing: **\n" + "** **\n" + "** - The average shortest path length between 'node' and **\n" + "** all the other nodes **\n" + "** - The maximum distance to any other node (eccentricity) **\n" + "** - The number of nodes at distance 1, 2, 3, .... from 'node' **\n" + "** **\n" + "********************************************************************\n" + " This is Free Software - You can use and distribute it under \n" + " the terms of the GNU General Public License, version 3 or later\n\n" + " Please visit http://www.complex-networks.net for more information\n\n" + " (c) Vincenzo Nicosia 2010-2017 (v.nicosia@qmul.ac.uk)\n" + "********************************************************************\n\n" + ); + printf("Usage: %s <graph_in> <node>\n\n" , argv[0]); +} + + +/* + * Add 'k' to a list of predecessors + */ + +void add_predecessor(unsigned int **pred, unsigned int k){ + + (*pred)[0] += 1; + *pred = realloc(*pred, ((*pred)[0] + 1) * sizeof(unsigned int)); + (*pred)[ (*pred)[0] ] = k; +} + + + +/* + * + * This is the implementation of the Breadth-First Search algorithm + * (BFS) to compute the shortest paths, and the distances, between a + * given node 'i' and all the other nodes of a graph. + * + */ +unsigned int** compute_shortest_paths(unsigned int N, unsigned int *J_slap, unsigned int *r_slap, + unsigned int i, unsigned int **dist){ + + unsigned int j, k, cur_node; + unsigned int *marked, **preds; + unsigned int d; + unsigned int n, nd, ndp; + + *dist = malloc(N * sizeof(unsigned int)); + marked = malloc(N * sizeof(unsigned int)); + preds = malloc(N * sizeof(unsigned int *)); + + for(j=0; j<N; j ++){ + (*dist)[j] = N; + preds[j] = malloc(sizeof(unsigned int)); + preds[j][0] = 0; /* The list of predecessors is empty! */ + } + (*dist)[i] = 0; + marked[0] = i; + d = 0; + n = 0; + nd = 1; + ndp = 0; + while (d<N && nd > 0){ + for(k = n; k< n+nd; k ++){ + cur_node = marked[k]; + for (j=r_slap[cur_node]; j<r_slap[cur_node +1] ; j++){ + if ( (*dist)[ J_slap[j] ] == d+1){ + add_predecessor((unsigned int **)(preds + J_slap[j]), cur_node); + } + if ( (*dist)[ J_slap[j] ] == N){ + (*dist)[ J_slap[j] ] = d+1; + marked[n + nd + ndp] = J_slap[j]; + add_predecessor(preds + J_slap[j], cur_node); + ndp +=1; + } + } + + } + n = n + nd; + nd = ndp; + ndp = 0; + d += 1; + } + free(marked); + return preds; +} + + +void dump_avg_max_hist(unsigned int *dists, unsigned int N){ + + unsigned int i; + double res = 0; + double max = 0; + double *hist; + + for (i=0; i<N; i++){ + res += dists[i]; + if (dists[i] > max) + max = dists[i]; + } + hist = malloc((max + 1) * sizeof(double)); + for (i=0; i<=max; i++){ + hist[i] = 0; + } + for (i=0; i<N; i++){ + if(dists[i]){ + hist[dists[i]] ++; + } + } + + res = res/(N-1); + + printf("%g %g", res, max); + for (i=1; i<=max; i++){ + printf(" %g", hist[i]); + } + printf("\n"); + free(hist); +} + + + + +int main(int argc, char *argv[]){ + + unsigned int *J_slap=NULL, *r_slap=NULL; + unsigned int K, N, i; + unsigned int **preds, *dists=NULL; + FILE *filein; + + if (argc < 3){ + usage(argv); + exit(1); + } + + if (!strcmp(argv[1], "-")){ + /* take the input from STDIN */ + filein = stdin; + } + else { + filein = openfile_or_exit(argv[1], "r", 2); + } + + read_slap(filein, &K, &N, &J_slap, &r_slap); + fclose(filein); + i = atoi(argv[2]); + if (i>N){ + printf("Node id '%d' does not exist!!!! Exiting....\n", i); + exit(3); + } + preds = compute_shortest_paths(N, J_slap, r_slap, i, &dists); + dump_avg_max_hist(dists, N); + + /* Cleanup */ + + for (i=0; i<N; i++){ + free(preds[i]); + } + free(preds); + free(dists); + free(J_slap); + free(r_slap); +} |