local void upward_pass(kdxptr kd, int cell)
{
kdnode *ntab = kd->ntab;
if (ntab[cell].dim != -1) { // not a terminal node?
upward_pass(kd, Lower(cell));
upward_pass(kd, Upper(cell));
combine_nodes(&ntab[cell], &ntab[Lower(cell)], &ntab[Upper(cell)]);
} else // scan bodies in node
set_bounds(&ntab[cell].bnd, kd->bptr, ntab[cell].first, ntab[cell].last);
}
void FMM2D::recalculate()
{
if (!m_tree) {
build_tree();
}
reset();
upward_pass();
downward_pass();
}
void FMM2D::calculate(bool precond)
{
reset();
m_make_prec = precond;
build_tree();
upward_pass();
downward_pass();
m_make_prec = false;
}
void build_kdtree(kdxptr kd, int nbucket)
{
int k, n, i, d, m, j, ct;
kdnode *ntab;
n = kd->ngas;
k = 1;
while (n > nbucket) {
n = n>>1;
k = k<<1;
}
kd->nnode = k<<1;
kd->nsplit = k;
ntab = kd->ntab = (kdnode *) allocate(kd->nnode * sizeof(kdnode));
ntab[KDROOT].first = 0; /* initialize root node */
ntab[KDROOT].last = kd->ngas-1;
ntab[KDROOT].bnd = kd->bnd;
i = KDROOT;
ct = KDROOT;
SetNext(ct);
for ( ; ; ) { /* loop splitting nodes */
if (i < kd->nsplit) {
d = 0; /* find longest dimension */
for (j=1; j<3; ++j) {
if (ntab[i].bnd.maxb[j]-ntab[i].bnd.minb[j] >
ntab[i].bnd.maxb[d]-ntab[i].bnd.minb[d])
d = j;
}
m = median_index(kd->bptr, d, ntab[i].first, ntab[i].last);
ntab[i].dim = d;
ntab[i].split = Pos(kd->bptr[m])[d];
ntab[Lower(i)].bnd = ntab[i].bnd;
ntab[Lower(i)].bnd.maxb[d] = ntab[i].split;
ntab[Lower(i)].first = ntab[i].first;
ntab[Lower(i)].last = m-1;
ntab[Upper(i)].bnd = ntab[i].bnd;
ntab[Upper(i)].bnd.minb[d] = ntab[i].split;
ntab[Upper(i)].first = m;
ntab[Upper(i)].last = ntab[i].last;
i = Lower(i);
} else {
ntab[i].dim = -1;
SetNext(i);
if (i == ct) break;
}
}
upward_pass(kd, KDROOT);
}