//**********************************************************************
//**********************************************************************
///a function that do a rewiring preserving the degree distribution
int rewiring_Pk(GRAPH* G,int num_rewires,gsl_rng * randgsl){
printf("Rewiring preserving P(k)...\n");fflush(stdout);
int i,pos_r,pos_s,r1,r2,s1,s2;
for(i=0;i<num_rewires*G->E;++i){
while(!choose_2_edges_random(G,&pos_r,&pos_s,randgsl)){} ///we try to find two edges avoiding selfedges and multipledges
r1 = G->edge[pos_r].s; /// the nodes first link are
r2 = G->edge[pos_r].d;
s1 = G->edge[pos_s].s; /// the nodes second link are
s2 = G->edge[pos_s].d;
swap_edges(G,s1,s2,r1,r2); /// we swap the two links
G->edge[pos_r].d = s2; /// we modify the edge vector
G->edge[pos_s].d = r2;
}
return 1;
}
//**********************************************************************
//**********************************************************************
int rewiring_Cbar_annealing(GRAPH G,double B,double increment,double accmin,int rewires,gsl_rng* randgsl){
double Caim = G.Ccoef;
/***********************************************************************
we create a random network with the same degree sequence
************************************************************************/
rewiring_Pk(G,rewires,randgsl);
double C = clustering_coeff(G);
double Cnew = C;
printf("Caim %f Cinitial %f\n",Caim,C);
/***********************************************************************
we do the rewiring preserving the C(k)
************************************************************************/
int s1,s2,r1,r2,pos_r,pos_s; /// rewiring variables that will store the proposed rewiring
double p,AH;
int accepted=0,rewirestemp=0,pirem=0; /// during the proces we count how many proposals rewirings are with AH>0, AH<o and AH=0
double averAH = 0,averAHneg = 0,averAHpos = 0,oldacc=0;
int numAH0 = 0,numAHneg = 0,numAHpos = 0;
double H = fabs(C - Caim); /// initial energy
/******** we start the rewiring *************/
printf("Annealed rewiring fixing the clustering coefficient...\n");fflush(stdout);
time_t start,end; /// we will measure the time
double dif;
time (&start);
int i;
for(i=1; oldacc>accmin || i<rewires*G.E+2 ;++i){
while(!choose_2_edges_random(G,&pos_r,&pos_s,randgsl)){} /// we try to find two edges avoiding selfedges and multipledges
r1 = G.edge[pos_r].s; /// the nodes are
r2 = G.edge[pos_r].d;
s1 = G.edge[pos_s].s;
s2 = G.edge[pos_s].d;
AH = calc_AH_Cbar(G,s1,s2,r1,r2,C,&Cnew,Caim); /// we calculate the increment of energy that would cause the rewiring
averAH = averAH + fabs(AH); ///we also counbt the average AH of the proposals
if(AH < 0.) { /// we count how many proposals have AH > 0
numAHneg++;
averAHneg = averAHneg + AH;
}
else if (AH > 0.) { /// we count how many proposals have AH < 0
numAHpos++;
averAHpos = averAHpos + AH;
}
else numAH0++; /// we count how many proposals have AH = 0
p = gsl_rng_uniform(randgsl); /// we throw a random number (0,1)
/********** IF we acccept **************/
if( p < exp(-B*AH) ){
swap_edges(G,s1,s2,r1,r2); /// we make the proposed rewired
G.edge[pos_r].d = s2; /// we modify the edge vector
G.edge[pos_s].d = r2;
C = Cnew;
if(fabs(AH)>0.) accepted++; /// we coubt how many changes we accept
H = H + AH;
}
/********** IF we reject **************/
else {
Cnew = C;
}
rewirestemp++;
/********** we reduce the temperature and we check the acceptance **************/
if(rewirestemp > rewires*G.E ) { ///we try to find the appropiate temperature in order to have the desire acceptation
printf("acceptance rate = %f " ,(double)accepted/(numAHneg+numAHpos)); /// the acceptance
//printf("AH = %f " ,averAH/(numAHneg+numAHpos)); /// the average energy of the proposed swaps
//printf("numAHneg = %f AHneg = %e ",(double)numAHneg/rewirestemp,averAHneg/numAHneg); /// the proportion of negative energy swaps and the average
//printf("numAHpos = %f AHpos = %e ",(double)numAHpos/rewirestemp,averAHpos/numAHpos); /// the proportion of positive energy swaps and the average
//printf("numAH0=%f " ,(double)numAH0/rewirestemp); /// the proportion of proposals that do not change the energy
printf("Beta=%e Energy=%e\n" ,B,H); /// the temperature and the energy
fflush(stdout);
if( ((double)accepted/(numAHneg+numAHpos)) > oldacc && i > rewires*G.E + 2 ) pirem++; /// in case we havethe acceptance has increased 10 times the rewiring proces
if(pirem>30) break;
oldacc = ((double)accepted/(numAHneg+numAHpos)); /// we save the old acceptance in order to compare with the next one
accepted = 0; /// we put to zero all the acceptance counters
rewirestemp = 0;
averAH = 0; numAHneg = 0;averAHneg = 0;
numAH0 = 0; numAHpos = 0;averAHpos = 0;
B = B*increment; /// we reduce the temperature
}
}
time (&end); ///we count the rewiring time and take conclusions
dif = difftime (end,start);
printf ("You rewired the entire network %.2f times with %.2lf seconds.\n",(double)i/G.E, dif );
printf("Cfinal %f\n",C);
/***********************************************************************
we free the memory
************************************************************************/
return 0;
}
