hkm_t *hkm_learn (int n, int d, int nlevel, int bf,
const float *points, int nb_iter_max, int nt, int verbose,
int **clust_assign_out)
{
int i, l, parent, k = 1;
hkm_t *hkm = hkm_new (d, nlevel, bf);
/* the absolute assignement of all points and the sizes of clusters */
int *node_assign = calloc (sizeof (int), n);
/* the buffer that receives the vectors gathered by parent node */
float *v = fvec_new (n * d);
/* Initialization */
for (l = 0; l < nlevel; l++) {
/* sort the vectors depending on which cluster they have been assigned to,
and compute the number of vectors assigned to each cluster
*** NOTE: to replace with the k_max function of ivfgeo
-> put this function in a separate library */
int *node_assign_idx = malloc (sizeof (*node_assign_idx) * n);
ivec_sort_index (node_assign, n, node_assign_idx);
/* Re-order the vectors depending on the previous order */
for (i = 0; i < n ; i++)
memmove (v + d * i, points + d * node_assign_idx[i],
sizeof (*points) * d);
/* k is the number of nodes/leaves at this level */
int pos = 0;
for (parent = 0; parent < k ; parent++) {
/* Count the number of vectors assigned to this internal node */
int nassign = 0;
while (pos + nassign < n)
if (node_assign[node_assign_idx[pos + nassign]] == parent)
nassign++;
else break;
if (verbose)
fprintf (stderr, "[Level %d | Parent %d] nassign=%d | pos=%d", l, parent, nassign, pos);
if (nassign == 0) {
fprintf (stderr, "# Problem2: no enough vectors in a node\n");
exit (1);
}
/* Perform the clustering on this subset of points */
int *clust_assign = ivec_new (nassign);
float * centroids = fvec_new (bf * d);
int nt = count_cpu();
int flags = nt | KMEANS_INIT_RANDOM | KMEANS_QUIET;
float err = kmeans (d, nassign, bf, nb_iter_max, v + d * pos, flags,
0, 1, centroids, NULL, clust_assign, NULL);
if (verbose)
fprintf (stderr, "-> err = %.3f\n", err);
memcpy (hkm->centroids[l] + d * parent * bf, centroids,
d * bf * sizeof (*centroids));
/* Update the indexes for those points */
for (i = 0; i < nassign; i++) {
int truepos = node_assign_idx[pos + i];
node_assign[truepos] = node_assign[truepos] * bf + clust_assign[i];
}
free (centroids);
free (clust_assign);
pos += nassign;
}
k *= bf;
free (node_assign_idx);
}
if(clust_assign_out) {
*clust_assign_out = (int *) malloc (n * sizeof (int));
memcpy (*clust_assign_out, node_assign, n * sizeof (int));
}
free (node_assign);
free (v);
return hkm;
}
void vlad_compute(int k, int d, const float *centroids, int n, const float *v,int flags, float *desc)
{
int i,j,l,n_quantile,i0,i1,ai,a,ma,ni;
int *perm ;
float un , diff;
float *tab,*u,*avg,*sum,*mom2,*dists;
int *hist,*assign;
if(flags<11 || flags>=13)
{
assign=ivec_new(n);
nn(n,k,d,centroids,v,assign,NULL,NULL);
if(flags==6 || flags==7)
{
n_quantile = flags==6 ? 3 : 1;
fvec_0(desc,k*d*n_quantile);
perm = ivec_new(n);
tab = fvec_new(n);
ivec_sort_index(assign,n,perm);
i0=0;
for(i=0;i<k;i++)
{
i1=i0;
while(i1<n && assign[perm[i1]]==i)
{
i1++;
}
if(i1==i0) continue;
for(j=0;j<d;j++)
{
for(l=i0;l<i1;l++)
{
tab[l-i0]=v[perm[l]*d+j];
}
ni=i1-i0;
fvec_sort(tab,ni);
for(l=0;l<n_quantile;l++)
{
desc[(i*d+j)*n_quantile+l]=(tab[(l*ni+ni/2)/n_quantile]-centroids[i*d+j])*ni;
}
}
i0=i1;
}
free(perm);
free(tab);
}
else if(flags==5)
{
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
desc[assign[i]*d+j]+=v[i*d+j];
}
}
}
else if(flags==8 || flags==9)
{
fvec_0(desc,k*d);
u = fvec_new(d);
for(i=0;i<n;i++)
{
fvec_cpy(u,v+i*d,d);
fvec_sub(u,centroids+assign[i]*d,d);
un=(float)sqrt(fvec_norm2sqr(u,d));
if(un==0) continue;
if(flags==8)
{
fvec_div_by(u,d,un);
} else if(flags==9)
{
fvec_div_by(u,d,sqrt(un));
}
fvec_add(desc+assign[i]*d,u,d);
}
free(u);
}
else if(flags==10)
{
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
desc[assign[i]*d+j]+=v[i*d+j];
}
}
for(i=0;i<k;i++)
{
fvec_normalize(desc+i*d,d,2.0);
}
}
else if(flags==13)
{
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
desc[assign[i]*d+j]+=(float)sqr(v[i*d+j]-centroids[assign[i]*d+j]);
}
}
}
else if(flags==14)
{
avg = fvec_new_0(k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
avg[assign[i]*d+j]+=v[i*d+j]-centroids[assign[i]*d+j];
}
}
hist=ivec_new_histogram(k,assign,n);
for(i=0;i<k;i++)
{
if(hist[i]>0)
{
for(j=0;j<d;j++)
{
avg[i*d+j]/=hist[i];
}
}
}
free(hist);
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
desc[assign[i]*d+j]+=(float)(sqr(v[i*d+j]-centroids[assign[i]*d+j]-avg[assign[i]*d+j]));
}
}
fvec_sqrt(desc,k*d);
free(avg);
}
else if(flags==15)
{
fvec_0(desc,k*d*2);
sum = desc;
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
sum[assign[i]*d+j]+=v[i*d+j]-centroids[assign[i]*d+j];
}
}
hist = ivec_new_histogram(k,assign,n);
mom2 = desc+k*d;
for(i=0;i<n;i++)
{
ai=assign[i];
for(j=0;j<d;j++)
{
mom2[ai*d+j]+=(float)(sqr(v[i*d+j]-centroids[ai*d+j]-sum[ai*d+j]/hist[ai]));
}
}
fvec_sqrt(mom2,k*d);
free(hist);
}
else if(flags==17)
{
fvec_0(desc,k*d*2);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
diff=v[i*d+j]-centroids[assign[i]*d+j];
if(diff>0)
{
desc[assign[i]*d+j]+=diff;
}
else
{
desc[assign[i]*d+j+k*d]-=diff;
}
}
}
}
else
{
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
desc[assign[i]*d+j]+=v[i*d+j]-centroids[assign[i]*d+j];
}
}
if(flags==1)
{
hist=ivec_new_histogram(k,assign,n);
/* printf("unbalance factor=%g\n",ivec_unbalanced_factor(hist,k)); */
for(i=0;i<k;i++)
{
for(j=0;j<d;j++)
{
desc[i*d+j]/=hist[i];
}
}
free(hist);
}
if(flags==2)
{
for(i=0;i<k;i++)
{
fvec_normalize(desc+i*d,d,2.0);
}
}
if(flags==3 || flags==4)
{
assert(!"not implemented");
}
if(flags==16)
{
hist=ivec_new_histogram(k,assign,n);
for(i=0;i<k;i++)
{
if(hist[i]>0)
{
fvec_norm(desc+i*d,d,2);
fvec_mul_by(desc+i*d,d,sqrt(hist[i]));
}
}
free(hist);
}
}
free(assign);
}
else if(flags==11 || flags==12)
{
ma=flags==11 ? 4 : 2;
assign=ivec_new(n*ma);
dists=knn(n,k,d,ma,centroids,v,assign,NULL,NULL);
fvec_0(desc,k*d);
for(i=0;i<n;i++)
{
for(j=0;j<d;j++)
{
for(a=0;a<ma;a++)
{
desc[assign[ma*i+a]*d+j]+=v[i*d+j]-centroids[assign[ma*i+a]*d+j];
}
}
}
free(dists);
free(assign);
}
}
