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authorKatolaZ <katolaz@freaknet.org>2017-09-27 15:06:31 +0100
committerKatolaZ <katolaz@freaknet.org>2017-09-27 15:06:31 +0100
commit3aee2fd43e3059a699af2b63c6f2395e5a55e515 (patch)
tree58c95505a0906ed9cfa694f9dbd319403fd8f01d /src/ba/ba.c
First commit on github -- NetBunch 1.0
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+/**
+ * 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 grows a network with N nodes using the linear
+ * preferential attachment model proposed by Barabasi and
+ * Albert. Each new node creates m links, and the initial (seed)
+ * network is a ring of n0>=m nodes.
+ *
+ *
+ * References:
+ *
+ * [1] A.-L. Barabasi, R. Albert, "Emergence of scaling in random
+ * networks", Science 286, 509-512 (1999).
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+void usage(char *argv[]){
+ printf("********************************************************************\n"
+ "** **\n"
+ "** -*- ba -*- **\n"
+ "** **\n"
+ "** Grow a scale-free network of 'N' nodes using the linear **\n"
+ "** preferential attachment model (Barabasi-Albert). **\n"
+ "** The initial network is a ring of 'n0' nodes, and each new **\n"
+ "** node creates 'm' edges. **\n"
+ "** **\n"
+ "** The program prints on STDOUT the edge-list of the final **\n"
+ "** graph. **\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 2010-2017 (v.nicosia@qmul.ac.uk)\n\n"
+ "********************************************************************\n\n"
+ );
+ printf("Usage: %s <N> <m> <n0>\n", argv[0]);
+
+}
+
+
+
+int init_network(unsigned int **S, unsigned int n0){
+
+ int n;
+
+ for(n=0; n<n0; n++){
+ S[0][n] = n;
+ S[1][n] = (n+1) % n0;
+ }
+ return n;
+}
+
+int select_neighbour(unsigned int **S, unsigned int S_num){
+
+ int d;
+
+ d = rand()%(S_num * 2);
+ if (d < S_num)
+ return S[0][d];
+ else{
+ return S[1][d-S_num];
+ }
+}
+
+/* check if 'd' is already a neighbour of 'i' */
+
+int already_neighbour(unsigned int **S, unsigned int S_num, unsigned int j, unsigned int d){
+
+ int i;
+
+ for(i=S_num; i< S_num + j; i ++){
+ if (S[1][i] == d)
+ return 1;
+ }
+ return 0;
+}
+
+unsigned int grow_ba_network(unsigned int **S, unsigned int N,
+ unsigned int m, unsigned int n0, unsigned int S_num){
+
+ int i, j;
+ int n, d;
+
+ for(i=0; i<N-n0; i++){
+ /* Let's add a new node */
+ n = n0 + i; /* This is the id of the new node */
+ for(j=0; j<m; j++){
+ S[0][S_num+j] = n;
+ d = select_neighbour(S, S_num);
+ while(already_neighbour(S, S_num, j, d)){
+ d = select_neighbour(S, S_num);
+ }
+ S[1][S_num + j] = d;
+ }
+ S_num += m;
+ }
+ return S_num;
+}
+
+
+
+int main(int argc, char *argv[]){
+
+ unsigned int **S;
+ unsigned int S_num, S_size, i;
+ int m, n0, N;
+
+ if (argc < 4){
+ usage(argv);
+ exit(1);
+ }
+
+ srand(time(NULL));
+
+ N = atoi(argv[1]);
+ m = atoi(argv[2]);
+ n0 = atoi(argv[3]);
+ S_size = (N+n0) * m ;
+
+ if (N < 1){
+ fprintf(stderr, "N must be positive\n");
+ exit(1);
+ }
+ if(m > n0){
+ fprintf(stderr, "n0 cannot be smaller than m\n");
+ exit(1);
+
+ }
+ if (n0<1){
+ fprintf(stderr, "n0 must be positive\n");
+ exit(1);
+ }
+
+ if (m < 1){
+ fprintf(stderr, "m must be positive\n");
+ exit(1);
+ }
+
+ S = malloc(2 * sizeof(unsigned int*));
+ S[0] = malloc(S_size * sizeof(unsigned int));
+ S[1] = malloc(S_size * sizeof(unsigned int));
+
+ S_num = init_network(S, n0);
+ S_num = grow_ba_network(S, N, m, n0, S_num);
+ for(i=0; i<S_num; i ++){
+ printf("%d %d\n",S[0][i], S[1][i]);
+ }
+ free(S[0]);
+ free(S[1]);
+ free(S);
+}