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Add fast-fail detection for formula generation with excessive initial terms #593

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Merged
merged 5 commits into from
Nov 28, 2025
Merged

Add fast-fail detection for formula generation with excessive initial terms #593

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b86cc2b
Initial plan
Copilot Nov 15, 2025
7c685cf
Increase maxInitialTerms to support formula generation for A000033
Copilot Nov 15, 2025
b5a3f15
Add early failure detection for programs requiring too many initial t…
Copilot Nov 15, 2025
456c495
Improve formula generation performance by imposing tighter limits in …
Copilot Nov 28, 2025
9abafe5
Merge branch 'main' into copilot/enhance-formula-generator
ckrause Nov 28, 2025
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4 changes: 4 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
@@ -1,5 +1,9 @@
## [Unreleased]

### Enhancements

* Improve formula generation performance by imposing tighter limits on variant simplification

### Bugfixes

* Fix parsing error during stats generation
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10 changes: 8 additions & 2 deletions src/form/variant.cpp
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Expand Up @@ -39,7 +39,7 @@ bool VariantsManager::update(Variant new_variant) {
return false;
}
const auto num_terms = new_variant.definition.numTerms();
if (num_terms > 500) { // magic number
if (num_terms > 200) { // limit term count to reduce complexity
Log::get().debug("Skipping variant with " + std::to_string(num_terms) +
" terms");
return false; // too many terms
Expand All @@ -49,6 +49,10 @@ bool VariantsManager::update(Variant new_variant) {
// return false;
// }
auto& vs = variants[new_variant.func];
// limit number of variants per function to reduce O(n^4) complexity
if (vs.size() >= 20) {
return false;
}
// prevent rapid increases of variant sizes
if (!std::all_of(vs.begin(), vs.end(), [new_variant](const Variant& v) {
return v.used_funcs.size() + 1 >= new_variant.used_funcs.size();
Expand Down Expand Up @@ -196,7 +200,9 @@ bool simplifyFormulaUsingVariants(
Formula& formula, std::map<std::string, int64_t>& num_initial_terms) {
VariantsManager manager(formula, num_initial_terms);
bool found = false;
while (manager.numVariants() < 200) { // magic number
size_t iterations = 0;
while (manager.numVariants() < 100 && iterations < 50) { // tighter limits
iterations++;
if (findVariants(manager)) {
found = true;
} else {
Expand Down