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Diffstat (limited to 'src/betweenness/bet_dependency.c')
| -rw-r--r-- | src/betweenness/bet_dependency.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/betweenness/bet_dependency.c b/src/betweenness/bet_dependency.c new file mode 100644 index 0000000..2b55543 --- /dev/null +++ b/src/betweenness/bet_dependency.c @@ -0,0 +1,224 @@ +/** + * 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 betweenness dependency of all the nodes + * of a graph, using Brandes' algorithm, and counting all the + * shortest paths originating from a set of nodes (potentially the + * whole set of vertices). + * + * References: + * U. Brandes. "A Faster Algorithm for Betweenness + * Centrality". J. Math. Sociol. 25 (2001), 163-177. + * + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "utils.h" + + +void usage(char *argv[]){ + printf("********************************************************************\n" + "** **\n" + "** -*- bet_dependency -*- **\n" + "** **\n" + "** Compute the betweenness dependency of all the nodes of a **\n" + "** network due to the shortest paths originating from a set **\n" + "** of initial nodes. If no start node is specified, compute **\n" + "** the dependency due to all the nodes of the graph. If no end **\n" + "** node is specified, compute the dependency due to the nodes **\n" + "** between node_start and the last node of the graph. **\n" + "** **\n" + "** The dependency of each node is printed on standard output. **\n" + "** **\n" + "** **\n" + "********************************************************************\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" + " (c) Vincenzo Nicosia 2009-2017 (katolaz@yahoo.it)\n\n"); + printf("Usage: %s <graph_in> [<node_start> [<node_end>]]\n\n" , argv[0]); +} + +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; +} + + + +/* + * Returns a list of dependencies + */ +double* compute_bet_dependency(unsigned int N, unsigned int *J_slap, unsigned int *r_slap, + unsigned int n_start, unsigned int n_end){ + + int i, j, k, w, idx, cur_node; + unsigned int *marked, **preds, *dist, *nj; + double *delta, *cB; + 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 *)); + + nj = malloc(N * sizeof(unsigned int)); + delta = malloc(N * sizeof(double)); + cB = malloc(N * sizeof(double)); + + for (i=0; i<N; i++){ + cB[i] = 0; + preds[i] = NULL; + } + + for (j=n_start; j<=n_end && j<N; j++){ + for(i=0; i<N; i ++){ + dist[i] = N; + if (! preds[i]){ + preds[i] = malloc(sizeof(unsigned int)); + } + preds[i][0] = 0; /* The list of predecessors is now empty! */ + + nj[i] = 0; + delta[i]= 0; + } + dist[j] = 0; + nj[j] = 1; + marked[0] = j; + d = 0; + n = 0; + nd = 1; + ndp = 0; + while (d<N && nd > 0){ + for(i = n; i< n+nd; i ++){ + cur_node = marked[i]; + for (k=r_slap[cur_node]; k<r_slap[cur_node +1] ; k++){ + w = J_slap[k]; + if ( dist[w] == d+1){ + add_predecessor((unsigned int **)(preds + w), cur_node); + nj[w] += nj[cur_node]; + } + if ( dist[w] == N){ + dist[w] = d+1; + marked[n + nd + ndp] = w; + add_predecessor(preds + w, cur_node); + ndp +=1; + nj[w] += nj[cur_node]; + } + } + } + n = n + nd; + nd = ndp; + ndp = 0; + d += 1; + } + for (k= n-1; k>=1; k--){ + w = marked[k]; + for (idx=1; idx <= preds[w][0]; idx ++ ){ + i = preds[w][idx]; + delta[i] += 1.0 * nj[i] / nj[w] * (1 + delta[w]); + } + cB[w] += delta[w]; + } + } + free(dist); + free(marked); + for (i=0; i<N; i++){ + free(preds[i]); + } + free(preds); + free(nj); + free(delta); + + return cB; +} + + + +void dump_cB(double *cB, unsigned int N){ + + unsigned int i; + for (i=0; i<N; i++){ + printf("%g\n", cB[i]); + } +} + + +int main(int argc, char *argv[]){ + + unsigned int *J_slap=NULL, *r_slap=NULL; + unsigned int K, N; + unsigned int n_start, n_end; + double *cB; + FILE *filein; + + n_start = 0; + n_end = -1; + + switch (argc){ + + case 4: + n_end = atoi(argv[3]); + case 3: + n_start = atoi(argv[2]); + case 2: + break; + default: + usage(argv); + exit(1); + break; + } + + 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); + if (n_end == -1) + n_end = N-1; + cB = compute_bet_dependency(N, J_slap, r_slap, n_start, n_end); + dump_cB(cB, N); + + free(cB); + free(J_slap); + free(r_slap); + +} |