int getTopSimUsers(gk_csr_t *adjMat, int user, gk_fkv_t *topUsers, int nsim) {
//to store the restart distributon of vertices
float *pr;
int i, j, count;
int iter = 0;
gk_fkv_t *pRanks;
pr = (float*) malloc(sizeof(float)*adjMat->nrows);
//initialize the restart distribution for user
pr[user] = 1.0;
iter = gk_rw_PageRank(adjMat, 0.5, 0.000001, 100, pr);
fprintf(stderr, "Iter: %d\n", iter);
count = 0;
//count the non-zero values in pr and sort them
for (i = 0; i < adjMat->nrows; i++) {
if (pr[i] > 0 && i != user) {
count++;
}
}
//printf("Found %d similar users.\n", count);
pRanks = gk_fkvmalloc(count, "store page ranks");
for (i = 0, j = 0; i < adjMat->nrows; i++) {
if (pr[i] > 0 && i != user) {
pRanks[j].key = pr[i];
pRanks[j].val = i;
j++;
}
}
nsim = gk_min(nsim, count);
gk_dfkvkselect(count, nsim, pRanks);
gk_fkvsortd(nsim, pRanks);
gk_fkvcopy(nsim, pRanks, topUsers);
free(pr);
free(pRanks);
return nsim;
}
int main(int argc, char *argv[])
{
ssize_t i, j, niter;
params_t *params;
gk_csr_t *mat;
FILE *fpout;
/* get command-line options */
params = parse_cmdline(argc, argv);
/* read the data */
mat = gk_csr_Read(params->infile, GK_CSR_FMT_METIS, 1, 1);
/* display some basic stats */
print_init_info(params, mat);
if (params->ntvs != -1) {
/* compute the pr for different randomly generated restart-distribution vectors */
float **prs;
prs = gk_fAllocMatrix(params->ntvs, mat->nrows, 0.0, "main: prs");
/* generate the random restart vectors */
for (j=0; j<params->ntvs; j++) {
for (i=0; i<mat->nrows; i++)
prs[j][i] = RandomInRange(931);
gk_fscale(mat->nrows, 1.0/gk_fsum(mat->nrows, prs[j], 1), prs[j], 1);
niter = gk_rw_PageRank(mat, params->lamda, params->eps, params->niter, prs[j]);
printf("tvs#: %zd; niters: %zd\n", j, niter);
}
/* output the computed pr scores */
fpout = gk_fopen(params->outfile, "w", "main: outfile");
for (i=0; i<mat->nrows; i++) {
for (j=0; j<params->ntvs; j++)
fprintf(fpout, "%.4e ", prs[j][i]);
fprintf(fpout, "\n");
}
gk_fclose(fpout);
gk_fFreeMatrix(&prs, params->ntvs, mat->nrows);
}
else if (params->ppr != -1) {
/* compute the personalized pr from the specified vertex */
float *pr;
pr = gk_fsmalloc(mat->nrows, 0.0, "main: pr");
pr[params->ppr-1] = 1.0;
niter = gk_rw_PageRank(mat, params->lamda, params->eps, params->niter, pr);
printf("ppr: %d; niters: %zd\n", params->ppr, niter);
/* output the computed pr scores */
fpout = gk_fopen(params->outfile, "w", "main: outfile");
for (i=0; i<mat->nrows; i++)
fprintf(fpout, "%.4e\n", pr[i]);
gk_fclose(fpout);
gk_free((void **)&pr, LTERM);
}
else {
/* compute the standard pr */
int jmax;
float diff, maxdiff;
float *pr;
pr = gk_fsmalloc(mat->nrows, 1.0/mat->nrows, "main: pr");
niter = gk_rw_PageRank(mat, params->lamda, params->eps, params->niter, pr);
printf("pr; niters: %zd\n", niter);
/* output the computed pr scores */
fpout = gk_fopen(params->outfile, "w", "main: outfile");
for (i=0; i<mat->nrows; i++) {
for (jmax=i, maxdiff=0.0, j=mat->rowptr[i]; j<mat->rowptr[i+1]; j++) {
if ((diff = fabs(pr[i]-pr[mat->rowind[j]])) > maxdiff) {
maxdiff = diff;
jmax = mat->rowind[j];
}
}
fprintf(fpout, "%.4e %10zd %.4e %10d\n", pr[i],
mat->rowptr[i+1]-mat->rowptr[i], maxdiff, jmax+1);
}
gk_fclose(fpout);
gk_free((void **)&pr, LTERM);
}
gk_csr_Free(&mat);
/* display some final stats */
print_final_info(params);
}
