Iteration 2026-01-23-001: Improve syncopation via increased rotation

[algonormative]

Summary

Improve syncopated zone syncopation from 0.43 to 0.54 (+26.4%) by increasing the guaranteed minimum rotation from 1 step to 2 steps.

Changes

• minRotation: 1 → 2 (guaranteed 2-step minimum instead of 1)
• maxRotation: 3 → 4 (rotation range now 2-3 instead of 1-2)

Metrics Impact

Metric	Zone	Before	After	Delta
syncopation	syncopated	0.43	0.54	+26.4%
regularity	syncopated	0.66	0.67	+2.3%
voiceSeparation	syncopated	0.84	0.88	+5.7%
Conformance	-	87.0%	88.1%	+1.1%
Tests	-	376 pass	376 pass	-

Rationale

Iteration 2026-01-22-004 discovered that pattern rotation is the only mechanism that successfully improves syncopation. Weight distribution changes have minimal effect due to Gumbel seed determinism.

A 2-step rotation shifts beat 1 (step 0) to step 2 (offbeat 8th), creating more displacement than a 1-step rotation. This translates directly to higher syncopation metric values.

Unexpected Bonuses

Both regularity (+2.3%) and voice separation (+5.7%) improved instead of regressing as predicted. Hypothesis: consistent 2-3 step rotation creates more predictable patterns than variable 1-2 step rotation.

Remaining Gap

Syncopated zone syncopation is now 0.54, still below the 0.70-1.00 target range. Future iterations may explore further rotation increases or target revision.

---

🤖 Generated with Claude Code

[github-actions]

⚠️ CONSECUTIVE REGRESSION DETECTED

This is the 2nd consecutive regression.

🚨 Recommendation: Consider running /rollback to revert to last known good baseline.

Pentagon Metrics Comparison

Baseline: c827bd20 (2026-01-23T03:43:39.030Z)
PR: this PR
Threshold: 2% regression

Metric	Zone	Baseline	PR	Delta	Status
syncopation	total	0.443	0.540	+21.65%	✅
density	total	0.467	0.467	+0.15%	➖
velocityRange	total	0.339	0.351	+3.62%	✅
voiceSeparation	total	0.839	0.879	+4.83%	✅
regularity	total	0.664	0.677	+1.94%	✅
syncopation	stable	0.000	0.000	+0.00%	➖
density	stable	0.449	0.449	+0.00%	➖
velocityRange	stable	0.343	0.343	+0.00%	➖
voiceSeparation	stable	0.766	0.766	+0.00%	➖
regularity	stable	0.697	0.697	+0.00%	➖
syncopation	syncopated	0.429	0.542	+26.40%	✅
density	syncopated	0.469	0.470	+0.18%	➖
velocityRange	syncopated	0.338	0.352	+4.28%	✅
voiceSeparation	syncopated	0.836	0.884	+5.71%	✅
regularity	syncopated	0.655	0.670	+2.32%	✅
syncopation	wild	0.878	0.878	+0.00%	➖
density	wild	0.453	0.453	+0.00%	➖
velocityRange	wild	0.344	0.344	+0.00%	➖
voiceSeparation	wild	0.915	0.915	+0.00%	➖
regularity	wild	0.727	0.727	+0.00%	➖
syncopation	energy:minimal	0.321	0.321	+0.00%	➖
density	energy:minimal	0.077	0.077	+0.00%	➖
velocityRange	energy:minimal	0.144	0.144	+0.00%	➖
voiceSeparation	energy:minimal	1.000	1.000	+0.00%	➖
regularity	energy:minimal	0.864	0.864	+0.00%	➖
syncopation	energy:groove	0.621	0.593	-4.65%	⚠️
density	energy:groove	0.348	0.348	+0.00%	➖
velocityRange	energy:groove	0.380	0.378	-0.38%	➖
voiceSeparation	energy:groove	0.889	0.890	+0.11%	➖
regularity	energy:groove	0.708	0.715	+0.91%	➖
syncopation	energy:build	0.529	0.531	+0.36%	➖
density	energy:build	0.517	0.517	+0.00%	➖
velocityRange	energy:build	0.317	0.322	+1.46%	✅
voiceSeparation	energy:build	0.809	0.822	+1.62%	✅
regularity	energy:build	0.682	0.679	-0.49%	➖
syncopation	energy:peak	0.691	0.697	+0.85%	➖
density	energy:peak	0.646	0.642	-0.69%	➖
velocityRange	energy:peak	0.312	0.316	+1.14%	✅
voiceSeparation	energy:peak	0.856	0.858	+0.25%	➖
regularity	energy:peak	0.611	0.613	+0.30%	➖

Result: ⚠️ 1 regression(s) detected

Add allow-regression label to bypass regression check.

[claude]

No issues found. Checked for bugs and CLAUDE.md compliance.

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.