#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<time.h>
#define Nrunmax 1
#define T 1000


//This program produces the adjacency matrices of the Dorogovtsev et al  model 
//with aging of the nodes for different values of alpha using the format read by cytoscape

int *k;
float Norm,alpha;


int Choose(int it){
	int j,i2;
	float x;
	
	x=Norm*drand48();
	for(i2=0;i2<it;i2++){
		x-=pow((it-i2),-alpha)*k[i2];
		if(x<0){
			j=i2;
			break;
		}
	}
	
}

int main(int argc, char** argv){
	int i,j,i2,it;
	char filec[60];
	
	FILE *fp;
  

  /* open file for output */

	srand48(time(NULL));
	for (alpha=-1.;alpha<20.; alpha+=0.25){
	sprintf(filec,"aging_adj_%2.3f.sif",alpha);
	fp=fopen(filec,"w");
	k=calloc(T,sizeof(int));
	
	k[0]=1;
	k[1]=1;
		fprintf(fp, "%d xx %d\n", 1, 2);
	
	Norm=pow(2,-alpha)+pow(1,-alpha);
  	for(it=2;it<T;it++){
		j=Choose(it);
		k[j]++;
		k[it]++;
		Norm=0;
		for(i2=0;i2<it+1;i2++){
			Norm+=pow(it+1-i2,-alpha)*k[i2];
		}
		fprintf(fp, "%d xx %d\n", it+1, j+1);
	}
	fclose(fp);
	}
	free (k);
	
	
	return 0;	
}