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kohonen:: triangulate in 3D manifolds

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Zeno Rogue 2021-07-18 11:40:03 +02:00
parent 04c9bd193a
commit cebb0180a5
1 changed files with 85 additions and 54 deletions
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121
rogueviz/kohonen.cpp
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@ -228,75 +228,106 @@ void coloring() {
ld precise_placement = 1.6;
bool neighbor_dir(cell *c, int a, int b) {
if(a == b) return false;
if(WDIM == 2)
return (a+1 == b) || (a-1 == b) || (a == 0 && b == c->type-1) || (b == 0 && a == c->type-1);
return currentmap->get_cellshape(c).dirdist[a][b] == 1;
}
bool triangulate(kohvec d, neuron& w, map<cell*, neuron*>& find, transmatrix& res) {
if(precise_placement < 1) return false;
vector<int> dirs;
vector<neuron*> other;
vector<kohvec> kv;
for(int i=0; i<WDIM; i++) {
ld bdiff = HUGE_VAL;
/* find the second neuron */
neuron *second = nullptr;
int dir2 = -1;
neuron *candidate = nullptr;
int cdir = -1;
forCellIdEx(c2, i, w.where) {
if(!find.count(c2)) continue;
auto w2 = find[c2];
double diff = vnorm(w2->net, d);
if(diff < bdiff) bdiff = diff, second = w2, dir2 = i;
if(1) {
bool valid = true;
for(int d: dirs)
if(!neighbor_dir(w.where, d, i))
valid = false;
if(!valid) continue;
}
if(diff < bdiff) bdiff = diff, candidate = w2, cdir = i;
}
if(cdir == -1) {
println(hlog, "not enough directions");
return false;
}
dirs.push_back(cdir);
other.push_back(candidate);
kv.push_back(candidate->net);
}
if(!second) return false;
/* find the third neuron */
neuron *third = nullptr; bdiff = HUGE_VAL;
int dir3 = -1;
forCellIdEx(c3, i, w.where) {
if(!find.count(c3)) continue;
if(valence() == 3 && !isNeighbor(c3, second->where)) continue;
auto w3 = find[c3];
double diff = vnorm(w3->net, d);
if(diff < bdiff) bdiff = diff, third = w3, dir3 = i;
}
if(!third) return false;
int q = isize(dirs);
const kohvec& a = w.net;
kohvec b = second->net;
kohvec c = third->net;
auto orig_d = d;
/* center at a */
vshift(b, a, -1);
vshift(c, a, -1);
for(int i=0; i<q; i++)
vshift(kv[i], a, -1);
vshift(d, a, -1);
transmatrix R;
hyperpoint coeff;
/* orthonormalize */
kohvec c1 = c;
kohvec d1 = d;
ld bd = vdot(b, b);
if(bd < 1e-12) return false;
ld s = vdot(c1, b) / bd;
vshift(c1, b, -s);
for(int i=0; i<q; i++) {
R[i][i] = vdot(kv[i], kv[i]);
if(R[i][i] < 1e-12) {
auto head = [] (const vector<ld>& v) { vector<ld> res; for(int i=0; i<10; i++) res.push_back(v[i]); return res; };
println(hlog, "dot too small, i=", i,", dirs=", dirs);
println(hlog, "a = ", head(a));
println(hlog, "orig d = ", head(d));
for(auto z: other)
println(hlog, "orig kv: ", head(z->net), " @ ", z->where);
for(auto z: kv)
println(hlog, "curr kv: ", head(z));
return false;
}
for(int j=i+1; j<q; j++) {
R[i][j] = vdot(kv[i], kv[j]) / R[i][i];
vshift(kv[j], kv[i], -R[i][j]);
}
coeff[i] = vdot(d, kv[i]) / R[i][i];
}
ld db = vdot(d1, b) / bd;
ld cd = vdot(c1, c1);
if(cd < 1e-12) return false;
ld dc = vdot(d1, c1) / cd;
for(int i=q-1; i>=0; i--) {
for(int j=0; j<i; j++)
coeff[j] -= coeff[i] * R[j][i];
}
// b is: (1,0)
// c is: (s,1)
/* rescale if out of the simplex */
for(int i=0; i<q; i++)
if(coeff[i] < 0) {
coeff /= (1-coeff[i]);
coeff[i] = 0;
}
// d is: (db,dc) = dc * (s,1) + (db-dc*s) * (1,0)
ld total = 0;
for(int i=0; i<q; i++) total += coeff[i];
if(total > 1) coeff /= total, total = 1;
db -= dc * s;
coeff /= precise_placement;
if(db < 0) dc = dc / (1-db), db = 0;
if(dc < 0) db = db / (1-dc), dc = 0;
ld overflow = db + dc - 1;
if(overflow > 0) tie(db,dc) = make_pair(db/(db+dc), dc/(db+dc));
db /= precise_placement, dc /= precise_placement;
hyperpoint h = (1-dc-db) * C0 + db * tC0(currentmap->adj(w.where, dir2)) + dc * tC0(currentmap->adj(w.where, dir3));
hyperpoint h = (1-total) * C0;
for(int i=0; i<q; i++) h += coeff[i] * tC0(currentmap->adj(w.where, dirs[i]));
h = normalize(h);
res = rgpushxto0(h);