// the cols contains codevectors
double kmeansiter(Array<vec> &DB, mat &codebook)
{
int DIM = DB(0).length(), SIZE = codebook.cols(), T = DB.length();
vec x, xnum(SIZE);
mat xsum(DIM, SIZE);
int MinIndex, i, j, k;
double MinS, S, D, *xp, *cp;
xsum.clear();
xnum.clear();
D = 1E20;
D = 0;
for (k = 0;k < T;k++) {
x = DB(k);
xp = x._data();
MinS = 1E20;
MinIndex = 0;
for (i = 0;i < SIZE;i++) {
cp = &codebook(0, i);
S = sqr(xp[0] - cp[0]);
for (j = 1;j < DIM;j++) {
S += sqr(xp[j] - cp[j]);
if (S >= MinS) goto sune;
}
MinS = S;
MinIndex = i;
sune:
void();
}
D += MinS;
cp = &xsum(0, MinIndex);
for (j = 0;j < DIM;j++) {
cp[j] += xp[j];
}
xnum(MinIndex)++;
}
for (i = 0;i < SIZE;i++) {
for (j = 0;j < DIM;j++) {
codebook(j, i) = xsum(j, i) / xnum(i);
}
}
return D;
}
static void
md5str_to_md5sum (const char *str, unsigned char *sum)
{
int i = 0;
int j = 0;
int ch = 0;
for (i = 0; i < 32; i++) {
if (!(i % 2)) {
ch = xnum (str[i]);
continue;
}
ch <<= 4;
ch += xnum (str[i]);
sum[j] = ch;
j++;
}
}
