unsigned int bselect(bitRankW32Int * br,unsigned int x) {
if(x==0) return 0;
// returns i such that x=rank(i) && rank(i-1)<x or n if that i not exist
// first binary search over first level rank structure
// then sequential search using popcount over a int
// then sequential search using popcount over a char
// then sequential search bit a bit
//binary search over first level rank structure
unsigned int n= br->n;
unsigned int s= br->s;
unsigned int b=br->b;
unsigned int l=0, r=n/s;
unsigned int integers = br->integers;
unsigned int factor = br->factor;
unsigned int mid=(l+r)/2;
unsigned int rankmid = br->Rs[mid];
while (l<=r) {
if (rankmid<x)
l = mid+1;
else
r = mid-1;
mid = (l+r)/2;
rankmid = br->Rs[mid];
}
//sequential search using popcount over a int
unsigned int left;
left=mid*factor;
x-=rankmid;
unsigned int j=br->data[left];
unsigned int ones = popcount(j);
while (ones < x) {
x-=ones;left++;
if (left > integers) return n;
j = br->data[left];
ones = popcount(j);
}
//sequential search using popcount over a char
left=left*b;
rankmid = popcount8(j);
if (rankmid < x) {
j=j>>8;
x-=rankmid;
left+=8;
rankmid = popcount8(j);
if (rankmid < x) {
j=j>>8;
x-=rankmid;
left+=8;
rankmid = popcount8(j);
if (rankmid < x) {
j=j>>8;
x-=rankmid;
left+=8;
}
bool MomentChi2Test ( struct HashInfo *info )
{
pfHash hash = info->hash;
const int size = info->hashbits / 8;
const int step = 3;
unsigned k = 0, s = 0;
unsigned long l, h, x;
unsigned mx = 0xfffffff0;
long double sa=0, saa=0, sb=0, sbb=0, n = mx/step;
hash(&k,sizeof(k),s,&l);
printf("Running 1st unseeded MomentChi2 for the low 32bits/step %d ... ", step);
fflush(NULL);
for(unsigned i=1; i<=mx; i+=step){
hash(&i,sizeof(i),s,&h);
x = popcount8(l^h); // check the lower 32bits only
x = x*x*x*x*x;
sa+=x; saa+=x*x; l=h;
}
sa/=n; saa=(saa/n-sa*sa)/n;
printf("%Lf - %Lf\n", sa, saa);
printf("Running 2nd seeded MomentChi2 for the low 32bits/step %d ... ", step);
fflush(NULL);
hash(&k,sizeof(k),s,&l);
for(unsigned i=1; i<=mx; i+=step){
hash(&k,sizeof(k),i,&h);
x = popcount8(l^h);
x = x*x*x*x*x;
sb+=x; sbb+=x*x; l=h;
}
sb/=n; sbb=(sbb/n-sb*sb)/n;
double chi2=(sa-sb)*(sa-sb)/(saa+sbb);
printf("%Lf - %Lf\nKeySeedMomentChi2:\t%g\t", sb, sbb, chi2);
fflush(NULL);
if (chi2 > 3.84145882069413)
{
printf("FAIL!!!!\n");
fflush(NULL);
return false;
}
else
{
printf("PASS\n");
fflush(NULL);
return true;
}
}