allemang.d/toddcox-visualize
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add comments to tc::solve

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This commit is contained in:
David Allemang
2022-09-14 10:35:38 -04:00
parent 34db72ba8e
commit 5dc9bb3dd6
1 changed files with 28 additions and 13 deletions
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41
tc/src/core.cpp
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@@ -33,6 +33,8 @@ namespace tc {
Cosets solve(const Group &group, const std::vector<size_t> &sub_gens) { Cosets solve(const Group &group, const std::vector<size_t> &sub_gens) {
auto ngens = group.ngens; auto ngens = group.ngens;
// region Initialize Cosets Table
Cosets cosets(ngens); Cosets cosets(ngens);
cosets.add_row(); cosets.add_row();
@@ -44,8 +46,11 @@ namespace tc {
if (g < ngens) if (g < ngens)
cosets.put(0, g, 0); cosets.put(0, g, 0);
} }
// endregion
auto rels = group.rels(); auto rels = group.rels();
// region Initialize Relation Tables
Tables rel_tables(rels); Tables rel_tables(rels);
std::vector<std::vector<int>> gen_map(ngens); std::vector<std::vector<int>> gen_map(ngens);
int rel_idx = 0; int rel_idx = 0;
@@ -69,36 +74,48 @@ namespace tc {
row.gnr = -1; row.gnr = -1;
} }
} }
// endregion
int idx = 0; int idx = 0;
int coset, gen, target, fact_idx, lst, gen_; int coset, gen, target, fact_idx, lst, gen_;
while (true) { while (true) {
// find next unknown product
while (idx < cosets.data.size() and cosets.get(idx) >= 0) while (idx < cosets.data.size() and cosets.get(idx) >= 0)
idx++; idx++;
// if there are none, then return
if (idx == cosets.data.size()) { if (idx == cosets.data.size()) {
// rel_tables.del_rows_to(idx / ngens); // todo unrolled linked list interval
// rel_tables.del_rows_to(idx / ngens);
break; break;
} }
// the unknown product must be a new coset, so add it
target = cosets.size(); target = cosets.size();
cosets.add_row(); cosets.add_row();
rel_tables.add_row(); rel_tables.add_row();
// queue of products that can be determined by the new coset
std::vector<int> facts; std::vector<int> facts;
facts.push_back(idx); facts.push_back(idx);
coset = idx / ngens; // todo unrolled linked list interval
gen = idx % ngens; // coset = idx / ngens;
// gen = idx % ngens;
// rel_tables.del_rows_to(coset); // rel_tables.del_rows_to(coset);
while (!facts.empty()) { while (!facts.empty()) {
// todo heap
std::sort(facts.begin(), facts.end(), std::greater<>());
fact_idx = facts.back(); fact_idx = facts.back();
facts.pop_back(); facts.pop_back();
if (cosets.get(fact_idx) != -1) // skip if this product was already determined
// todo try to avoid these duplications
if (cosets.get(fact_idx) != -1) {
continue; continue;
}
cosets.put(fact_idx, target); cosets.put(fact_idx, target);
@@ -117,32 +134,30 @@ namespace tc {
for (int table_idx: gen_map[gen]) { for (int table_idx: gen_map[gen]) {
auto &col = rel_tables.cols[table_idx]; auto &col = rel_tables.cols[table_idx];
auto &rel = rel_tables.rels[table_idx];
auto &trow = col[target]; auto &trow = col[target];
auto &crow = col[coset]; auto &crow = col[coset];
if (trow.lst_ptr == nullptr) { if (trow.lst_ptr == nullptr) {
Rel &ti = rel_tables.rels[table_idx];
trow.lst_ptr = crow.lst_ptr; trow.lst_ptr = crow.lst_ptr;
trow.gnr = crow.gnr + 1; trow.gnr = crow.gnr + 1;
if (crow.gnr < 0) if (crow.gnr < 0)
trow.gnr -= 2; trow.gnr -= 2;
if (trow.gnr == ti.mult) { if (trow.gnr == rel.mult) {
lst = *(trow.lst_ptr); lst = *(trow.lst_ptr);
delete trow.lst_ptr; delete trow.lst_ptr;
gen_ = ti.gens[(int) (ti.gens[0] == gen)]; gen_ = rel.gens[(int) (rel.gens[0] == gen)];
facts.push_back(lst * ngens + gen_); facts.push_back(lst * ngens + gen_);
} else if (trow.gnr == -ti.mult) { } else if (trow.gnr == -rel.mult) {
gen_ = ti.gens[ti.gens[0] == gen]; gen_ = rel.gens[rel.gens[0] == gen];
facts.push_back(target * ngens + gen_); facts.push_back(target * ngens + gen_);
} else if (trow.gnr == ti.mult - 1) { } else if (trow.gnr == rel.mult - 1) {
*(trow.lst_ptr) = target; *(trow.lst_ptr) = target;
} }
} }
} }
std::sort(facts.begin(), facts.end(), std::greater<>());
} }
for (int table_idx = 0; table_idx < rel_tables.size(); table_idx++) { for (int table_idx = 0; table_idx < rel_tables.size(); table_idx++) {