Close Julia parity test gaps: BicliqueCover, BMF, SAT→CircuitSAT, reduction paths

[GiggleLiu]

Summary

Closes #67 — closes all Julia parity test gaps identified in the coverage comparison.

• BicliqueCover & BMF parity tests: Added Julia fixtures and Rust evaluation tests for the 2 missing model problems
• SAT → CircuitSAT reduction: Full implementation converting CNF to boolean circuit (OR gates per clause + final AND gate), with closed-loop and JL parity tests
• Reduction-path parity tests: 3 tests mirroring Julia's test/reduction_path.jl (MaxCut→SpinGlass, MaxCut→QUBO, Factoring→SpinGlass via chained paths)
• Factoring → SpinGlass example: New chained reduction example matching Julia's examples/Ising.jl
• Julia fixture generation: Extended generate_testdata.jl with BicliqueCover/BMF serializers and reduction-path fixture exports
• Path finding API cleanup: Replaced name-level find_paths_by_name/find_shortest_path_by_name with variant-level find_all_paths and find_cheapest_path. Removed redundant find_shortest_path (use find_cheapest_path with MinimizeSteps). Removed unused cost functions (MinimizeWeighted, MinimizeMax, MinimizeLexicographic). Updated design.md.

Coverage after this PR

• Models: 18/18 problems tested (100%)
• Reductions: 14/14 Julia reductions tested (100%)
• Reduction paths: 3 chained path tests added

Test plan

• make test — all tests pass
• make clippy — no warnings
• New SAT→CircuitSAT reduction has closed-loop, unsatisfiable, and JL parity tests
• Reduction path tests verify solution extraction across multi-hop chains
• Reduction graph regenerated with new SAT→CircuitSAT edge
• All path-finding tests updated to variant-level API

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 99.21875% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.41%. Comparing base (5320302) to head (87332fc).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/rules/sat_circuitsat.rs	95.31%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #75      +/-   ##
==========================================
+ Coverage   96.38%   96.41%   +0.03%     
==========================================
  Files         190      193       +3     
  Lines       25306    25552     +246     
==========================================
+ Hits        24391    24636     +245     
- Misses        915      916       +1     

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[Copilot]

Pull request overview

This PR closes Julia parity test gaps by implementing missing model evaluation tests and reductions. It adds comprehensive test coverage for BicliqueCover and BMF problems, implements the SAT→CircuitSAT reduction with full test suite, adds three reduction path parity tests mirroring Julia's test/reduction_path.jl, and includes a new chained reduction example for Factoring→SpinGlass. The Julia fixture generation script has been extended with BicliqueCover/BMF serializers and reduction-path fixture exports.

Changes:

• Added BicliqueCover and BMF parity tests with Julia-generated fixtures
• Implemented SAT→CircuitSAT reduction with closed-loop, unsatisfiable, and single-clause tests
• Added 3 reduction path parity tests (MaxCut→SpinGlass, MaxCut→QUBO, Factoring→SpinGlass)
• New chained_reduction_factoring_to_spinglass example matching Julia's examples/Ising.jl
• Extended generate_testdata.jl with BicliqueCover/BMF evaluation functions and reduction path fixtures
• Updated reduction graph JSON with new SAT→CircuitSAT edge

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/rules/sat_circuitsat.rs	New SAT→CircuitSAT reduction converting CNF to boolean circuit (OR gates per clause + final AND gate)
src/unit_tests/rules/sat_circuitsat.rs	Comprehensive tests for SAT→CircuitSAT including closed-loop, unsatisfiable, and single-clause cases
src/unit_tests/rules/reduction_path_parity.rs	Three reduction path tests verifying solution extraction across multi-hop chains
src/unit_tests/models/specialized/biclique_cover.rs	Added Julia parity evaluation test for BicliqueCover
src/unit_tests/models/specialized/bmf.rs	Added Julia parity evaluation test for BMF
examples/chained_reduction_factoring_to_spinglass.rs	New example demonstrating Factoring→SpinGlass chain reduction
scripts/jl/generate_testdata.jl	Extended with BicliqueCover/BMF evaluation functions, reduction path fixture generation, and Random.seed!(42) for reproducibility
tests/data/jl/biclique_cover.json	New fixture file with BicliqueCover test data
tests/data/jl/bmf.json	New fixture file with BMF test data
tests/data/jl/path_*.json	Three new reduction path fixture files
tests/data/jl/*.json	Regenerated existing fixtures with pinned random seed for consistency
docs/src/reductions/reduction_graph.json	Added SAT→CircuitSAT edge to reduction graph
src/rules/mod.rs	Added sat_circuitsat module and ReductionSATToCircuit export
src/rules/graph.rs	Added reduction_path_parity tests module
tests/suites/examples.rs	Registered chained_reduction_factoring_to_spinglass example test
Makefile	Unrelated workflow improvement changing "Post summary" to "Create a pull request"

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[Copilot]

The Makefile changes appear to be unrelated to this PR's stated purpose of closing Julia parity test gaps. The change from "Post summary" to "Create a pull request" in the run-plan target seems like an independent workflow improvement that should be in a separate commit or PR.