Simplify variant system and clean up type hierarchy

[GiggleLiu]

Summary

• Simplify variant system: derive problem categories from module_path instead of manual annotation, use node indices in reduction graph JSON, drastically reducing reduction_graph.json size
• Clean up type hierarchy: introduce WeightElement trait and One type replacing Unweighted/Weights/NumericWeight, add SatisfactionProblem marker trait, make #[reduction] macro ReduceTo impls concrete instead of using hardcoded fallbacks
• Add Triangular graph type: introduce Triangular lattice graph (subtype of UnitDiskGraph) with a #[reduction]-based MIS reduction from SimpleGraph using the weighted triangular unit disk mapping (O(n²) overhead)
• Reorganize paper static files into docs/paper/static/ subdirectory

Test plan

• make test passes
• make clippy passes
• make fmt-check passes
• Reduction graph JSON is regenerated and valid
• Examples compile and run correctly

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 98.84488% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.08%. Comparing base (ee2494d) to head (0e8568a).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/rules/graph.rs	96.20%	3 Missing ⚠️
src/unit_tests/rules/graph.rs	98.03%	2 Missing ⚠️
src/unit_tests/rules/registry.rs	75.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
+ Coverage   97.01%   97.08%   +0.06%     
==========================================
  Files         178      186       +8     
  Lines       25540    25643     +103     
==========================================
+ Hits        24778    24895     +117     
+ Misses        762      748      -14     

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[Copilot]

Pull request overview

This PR refactors the library’s variant/type system by (1) simplifying variant/category metadata derivation (from module_path and node indices in the exported reduction graph JSON) and (2) cleaning up the weight + problem trait hierarchy (introducing WeightElement/One and SatisfactionProblem). It also updates docs, examples, and test fixtures to match the new schema and exports.

Changes:

• Replace Unweighted/Weights/NumericWeight with One + WeightElement and propagate the new metric (W::Sum) across models, rules, tests, and exports.
• Export a smaller reduction_graph.json by using node indices for edges and deriving category/doc links from ProblemSchemaEntry.module_path; update docs/visualization consumers accordingly.
• Make #[reduction] registrations require concrete ReduceTo impls (no type generics), and add/adjust concrete reductions (incl. MIS→GridGraph).

Reviewed changes

Copilot reviewed 68 out of 72 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/data/qubo/minimumvertexcover_to_qubo.json	Update fixture problem name to match renamed/standardized model naming.
tests/data/qubo/maximumsetpacking_to_qubo.json	Update fixture problem name to match renamed/standardized model naming.
tests/data/qubo/maximumindependentset_to_qubo.json	Update fixture problem name to match renamed/standardized model naming.
src/unit_tests/variant.rs	Update variant expectations to reflect reduced/changed variant keys and default handling.
src/unit_tests/types.rs	Replace Unweighted/Weights tests with One/WeightElement tests.
src/unit_tests/rules/travelingsalesman_ilp.rs	Formatting + updated constructors/expectations after type-system changes.
src/unit_tests/rules/sat_ksat.rs	Update test to target KSatisfiability<3> and clause-size assertions.
src/unit_tests/rules/registry.rs	Update registry tests to use One in variants.
src/unit_tests/rules/maximumsetpacking_qubo.rs	Switch test instances to MaximumSetPacking<f64> for QUBO reduction.
src/unit_tests/rules/maximumindependentset_gridgraph.rs	New unit tests for MIS reductions to GridGraph.
src/unit_tests/rules/graph.rs	Update tests for JSON edge indexing, module_path-derived category/doc paths, and One variants.
src/unit_tests/rules/circuit_spinglass.rs	Update generic bounds to WeightElement.
src/unit_tests/models/graph/traveling_salesman.rs	Formatting + updated constructors/expectations after type-system changes.
src/unit_tests/graph_types.rs	Update subtype registration assertions to use One.
src/types.rs	Introduce WeightElement + One; remove NumericWeight/Weights; alias Unweighted = One.
src/traits.rs	Add SatisfactionProblem marker trait.
src/rules/variants.rs	New concrete-variant registrations for “orphan” nodes needed by natural edges (using One).
src/rules/travelingsalesman_ilp.rs	Formatting-only changes in ILP encoding implementation.
src/rules/spinglass_maxcut.rs	Make ReduceTo impls concrete (i32); update bounds via WeightElement.
src/rules/sat_ksat.rs	Limit SAT→K-SAT registration to K=3; update macro + comments.
src/rules/registry.rs	Update “base/unweighted” detection to One.
src/rules/mod.rs	Wire in new MIS→GridGraph rule module and variants module.
src/rules/minimumvertexcover_minimumsetcovering.rs	Make ReduceTo impl concrete (i32) and use WeightElement in bounds.
src/rules/minimumvertexcover_maximumindependentset.rs	Make ReduceTo impls concrete (i32) and use WeightElement in bounds.
src/rules/maximumsetpacking_qubo.rs	Make reduction concrete for MaximumSetPacking<f64> → QUBO<f64>; simplify implementation.
src/rules/maximummatching_maximumsetpacking.rs	Make ReduceTo impl concrete (SimpleGraph, i32); update bounds.
src/rules/maximumindependentset_maximumsetpacking.rs	Make ReduceTo impls concrete (i32); update bounds.
src/rules/maximumindependentset_gridgraph.rs	New MIS(Simple/UnitDisk)→MIS(GridGraph) reduction using KSG mapping.
src/rules/graph.rs	Reduction graph JSON: edges reference node indices; categories/docs derived from schema module_path; API uses Problem::NAME.
src/rules/coloring_ilp.rs	Make ReduceTo concrete for KColoring<K, SimpleGraph> → ILP.
src/registry/schema.rs	Add module_path field to ProblemSchemaEntry.
src/models/specialized/paintshop.rs	Add schema module_path; variant() now returns empty vec.
src/models/specialized/factoring.rs	Add schema module_path; variant() now returns empty vec.
src/models/specialized/circuit.rs	Add schema module_path; implement SatisfactionProblem; variant() now empty.
src/models/specialized/bmf.rs	Add schema module_path; variant() now returns empty vec.
src/models/specialized/biclique_cover.rs	Add schema module_path; variant() now returns empty vec.
src/models/set/minimum_set_covering.rs	Migrate to WeightElement and W::Sum metrics; variant() emits only weight key; add schema module_path.
src/models/set/maximum_set_packing.rs	Migrate to WeightElement and W::Sum metrics; variant() emits only weight key; add schema module_path.
src/models/satisfiability/sat.rs	Add schema module_path; implement SatisfactionProblem; variant() now empty.
src/models/satisfiability/ksat.rs	Add schema module_path; implement SatisfactionProblem; variant() now only k.
src/models/optimization/spin_glass.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/optimization/qubo.rs	Migrate to WeightElement and W::Sum metrics; variant() emits only weight key; add schema module_path.
src/models/optimization/ilp.rs	Add schema module_path; variant() now empty.
src/models/mod.rs	Minor reordering of re-exports.
src/models/graph/traveling_salesman.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/mod.rs	Reorder module declarations/exports (no functional change).
src/models/graph/minimum_vertex_cover.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/minimum_dominating_set.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/maximum_matching.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/maximum_independent_set.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/maximum_clique.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/maximal_is.rs	Migrate to WeightElement and W::Sum metrics; variant() uses G::NAME; add schema module_path.
src/models/graph/max_cut.rs	Migrate to WeightElement and W::Sum metrics; update cut_size return type; add schema module_path.
src/models/graph/kcoloring.rs	Add schema module_path; implement SatisfactionProblem; variant() uses G::NAME.
src/lib.rs	Update exports/prelude for One/WeightElement and SatisfactionProblem; remove old types.
src/graph_types.rs	Update declared weight subtype chain to One → i32 → f64.
src/export.rs	Update variant metadata doc comment to reference One.
problemreductions-macros/src/lib.rs	Enforce concrete ReduceTo impls (no type generics); remove fallback override attributes.
examples/reduction_maximumsetpacking_to_qubo.rs	Switch example to MaximumSetPacking<f64> for QUBO reduction.
examples/export_petersen_mapping.rs	Update output paths to docs/paper/static/.
docs/src/reductions/reduction_graph.json	Regenerated reduction graph export using node indices + new variant/category scheme.
docs/src/introduction.md	Update JS visualization to consume indexed edges and improved labels/tooltips.
docs/src/design.md	Rename doc heading, add variant-system explanation and examples.
docs/src/SUMMARY.md	Update nav entry from Architecture→Design.
docs/plans/2026-02-14-type-system-cleanup-impl.md	Add implementation plan doc for this refactor.
docs/plans/2026-02-14-type-system-cleanup-design.md	Add design doc for the refactor.
docs/paper/static/petersen_source.json	Add paper static JSON output (new path).
docs/paper/reductions.typ	Update Typst to follow indexed-edge JSON and new static paths.
.claude/skills/issue-to-pr.md	Tighten issue template guidance for reduction examples.

Comments suppressed due to low confidence (2)

docs/src/design.md:106

• The variant examples/documentation still refer to Unweighted (e.g., MaximumIndependentSet<UnitDiskGraph, Unweighted> and ("weight", "Unweighted")), but the codebase now uses the unit-weight type One and variant strings like "One". Update these examples/text to use One (and adjust the note about omitting default fields accordingly) to avoid misleading readers.
  docs/src/design.md:143
• This weight-hierarchy section documents Unweighted → i32 → f64 and shows declare_weight_subtype!("Unweighted" => "i32"), but the implementation was renamed to One (see src/graph_types.rs). Please update the diagram/snippet (and any later references like Unweighted ≤ i32) to One → i32 → f64 so it matches the current variant metadata.

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[Copilot]

The #[reduction(overhead = { ... })] attribute inside impl_sat_to_ksat! has unusually deep indentation that doesn't match the surrounding style and is likely to fail fmt-check if the repo enforces rustfmt. Reformat this attribute (or run cargo fmt) so the macro expansion stays consistent with other reduction attributes in the crate.

[Copilot]

These inventory::submit! registrations are all written as single very-long lines. If the repo enforces rustfmt via make fmt-check, this file is likely to be reformatted (and may currently fail formatting checks). Consider formatting each submission as a multi-line block for consistency and to keep diffs stable.

[Copilot]

variantDefaults.weight is set to "Unweighted", but the reduction graph JSON and Problem::variant() now use "One" for unit-weight variants. This will cause base-variant detection (isBaseVariant) and label suppression to fail (e.g., default nodes will be treated as non-base and show "One" in labels). Update the default weight string to "One" (or accept both during a transition).

Suggested change

	var variantDefaults = { graph: 'SimpleGraph', weight: 'Unweighted' };
	var variantDefaults = { graph: 'SimpleGraph', weight: 'One' };

[Copilot]

Pull request overview

Copilot reviewed 77 out of 81 changed files in this pull request and generated no new comments.

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