void partition_sort_particles(int64_t min, int64_t max,
struct particle *particles, int64_t *assignments) {
int64_t minpivot, maxpivot, pivot, i, si, tmp;
struct particle tmp_p;
if (max-min < 2) return;
maxpivot = minpivot = assignments[min];
for (i=min+1; i<max; i++) {
if (assignments[i] > maxpivot) maxpivot = assignments[i];
if (assignments[i] < minpivot) minpivot = assignments[i];
}
if (minpivot==maxpivot) return;
pivot = minpivot + (maxpivot-minpivot)/2;
si = max-1;
#define SWAP(a,b) {tmp_p = particles[a]; particles[a] = particles[b]; \
particles[b] = tmp_p; tmp = assignments[a]; \
assignments[a] = assignments[b]; assignments[b] = tmp;}
for (i=min; i<si; i++)
if (assignments[i] > pivot) { SWAP(i, si); si--; i--; }
if (i==si && assignments[si]<=pivot) si++;
#undef SWAP
partition_sort_particles(min, si, particles, assignments);
partition_sort_particles(si, max, particles, assignments);
}
void build_fullfofs(void) {
int64_t i, sf, last_sf=-1, f=-1;
collapse_smallfofs();
num_smallfofs = 0;
partition_sort_particles(0, num_particles, root_p, particle_smallfofs);
for (i=0; i<num_particles; i++) {
if (particle_smallfofs[i] < 0) continue;
sf = particle_smallfofs[i];
if (sf != last_sf) {
if (f>-1) { fofs[f].num_p = (root_p + i) - fofs[f].particles; }
if ((f < 0) || (fofs[f].num_p >= MIN_HALO_PARTICLES)) f=add_new_fof();
fofs[f].particles = root_p + i;
last_sf = sf;
}
}
if (f>-1) {
fofs[f].num_p = (root_p + i) - fofs[f].particles;
if (fofs[f].num_p < MIN_HALO_PARTICLES) num_fofs--;
}
}
