Add iteration trace diagnostics for seed43

docs/iteration_trace.md

@@ -0,0 +1,85 @@
+# Iteration Trace
+
+Generated at 2026-04-02T16:11:39-07:00 by `scripts/record_iteration_trace.py`.
+
+## example_07_large_scale_routing_no_warm_start
+
+Results: 10 valid / 10 reached / 10 total.
+
+| Iteration | Penalty | Routed Nets | Completed | Conflict Edges | Dynamic Collisions | Nodes | Congestion Checks | Candidate Ids | Exact Pairs |
+| --: | --: | --: | --: | --: | --: | --: | --: | --: | --: |
+| 0 | 100.0 | 10 | 1 | 16 | 50 | 571 | 0 | 0 | 0 |
+| 1 | 140.0 | 10 | 2 | 12 | 54 | 253 | 974 | 2378 | 1998 |
+| 2 | 196.0 | 10 | 4 | 5 | 22 | 253 | 993 | 1928 | 1571 |
+| 3 | 274.4 | 10 | 6 | 2 | 10 | 100 | 437 | 852 | 698 |
+| 4 | 384.2 | 10 | 6 | 2 | 10 | 126 | 517 | 961 | 812 |
+| 5 | 537.8 | 10 | 6 | 2 | 10 | 461 | 1704 | 3805 | 3043 |
+
+Top nets by iteration-attributed nodes expanded:
+
+- `net_03`: 383
+- `net_06`: 292
+- `net_09`: 260
+- `net_00`: 210
+- `net_02`: 190
+- `net_08`: 168
+- `net_01`: 162
+- `net_07`: 61
+- `net_04`: 19
+- `net_05`: 19
+
+Top nets by iteration-attributed congestion checks:
+
+- `net_03`: 1242
+- `net_06`: 1080
+- `net_02`: 674
+- `net_01`: 534
+- `net_08`: 262
+- `net_00`: 229
+- `net_07`: 228
+- `net_09`: 176
+- `net_04`: 100
+- `net_05`: 100
+
+## example_07_large_scale_routing_no_warm_start_seed43
+
+Results: 10 valid / 10 reached / 10 total.
+
+| Iteration | Penalty | Routed Nets | Completed | Conflict Edges | Dynamic Collisions | Nodes | Congestion Checks | Candidate Ids | Exact Pairs |
+| --: | --: | --: | --: | --: | --: | --: | --: | --: | --: |
+| 0 | 100.0 | 10 | 1 | 16 | 50 | 571 | 0 | 0 | 0 |
+| 1 | 140.0 | 10 | 1 | 13 | 53 | 269 | 961 | 2562 | 2032 |
+| 2 | 196.0 | 10 | 4 | 3 | 15 | 140 | 643 | 1610 | 1224 |
+| 3 | 274.4 | 10 | 4 | 3 | 15 | 84 | 382 | 801 | 651 |
+| 4 | 384.2 | 10 | 6 | 2 | 10 | 170 | 673 | 1334 | 1072 |
+| 5 | 537.8 | 10 | 6 | 2 | 10 | 457 | 1671 | 3718 | 2992 |
+| 6 | 753.0 | 10 | 4 | 4 | 8 | 22288 | 89671 | 218513 | 171925 |
+| 7 | 1054.1 | 10 | 4 | 4 | 8 | 15737 | 29419 | 34309 | 28603 |
+| 8 | 1475.8 | 10 | 4 | 4 | 8 | 21543 | 41803 | 49314 | 41198 |
+
+Top nets by iteration-attributed nodes expanded:
+
+- `net_06`: 31604
+- `net_03`: 27532
+- `net_02`: 763
+- `net_09`: 286
+- `net_07`: 239
+- `net_00`: 233
+- `net_08`: 218
+- `net_05`: 134
+- `net_01`: 132
+- `net_04`: 118
+
+Top nets by iteration-attributed congestion checks:
+
+- `net_06`: 83752
+- `net_03`: 75019
+- `net_02`: 3270
+- `net_07`: 844
+- `net_08`: 540
+- `net_01`: 441
+- `net_05`: 425
+- `net_04`: 398
+- `net_09`: 288
+- `net_00`: 246
+

docs/optimization_pass_01_log.md

@@ -3629,3 +3629,14 @@ Findings:
 | example_07_large_scale_routing_no_warm_start | pair_local_search_attempts | - | 2.0000 | - |
 | example_07_large_scale_routing_no_warm_start | pair_local_search_accepts | - | 2.0000 | - |
 | example_07_large_scale_routing_no_warm_start | pair_local_search_nodes_expanded | - | 68.0000 | - |
+
+## Step 64 seed-43 iteration-trace diagnosis
+
+Measured on 2026-04-02T16:11:39-07:00.
+
+Findings:
+
+- Added `capture_iteration_trace` plus `scripts/record_iteration_trace.py` and tracked the first `seed 42` vs `seed 43` no-warm comparison in `docs/iteration_trace.json` and `docs/iteration_trace.md`.
+- The pathological `seed 43` basin is not front-loaded. It matches the solved `seed 42` path through iteration `5`, then falls into three extra iterations with only `4` completed nets and `4` conflict edges.
+- The late blowup is concentrated in two nets, not the whole routing set: `net_06` contributes `31604` attributed nodes and `83752` congestion checks, while `net_03` contributes `27532` nodes and `75019` congestion checks.
+- This points the next optimization work at late-iteration reroute behavior for a small subset of nets rather than another global congestion or pair-local-search change.

docs/performance.md

@@ -9,6 +9,7 @@ The default baseline table below covers the standard example corpus only. The he
 
 Use `scripts/characterize_pair_local_search.py` when you want a small parameter sweep over example_07-style no-warm runs instead of a single canary reading.
 The current tracked sweep output lives in `docs/pair_local_characterization.json` and `docs/pair_local_characterization.md`.
+Use `scripts/record_iteration_trace.py` when you want a seed-42 vs seed-43 negotiated-congestion attribution run; the current tracked output lives in `docs/iteration_trace.json` and `docs/iteration_trace.md`.
 
 | Scenario | Duration (s) | Total | Valid | Reached | Iter | Nets Routed | Nodes | Ray Casts | Moves Gen | Moves Added | Dyn Tree | Visibility Builds | Congestion Checks | Verify Calls |
 | :-- | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: |
@@ -36,6 +37,8 @@ For the current accepted branch, the most important performance-only canary is `
 
 The latest tracked characterization sweep confirms there is no smaller stable pair-local smoke case under the `<=1.0s` rule, so the 10-net no-warm-start canary remains the primary regression target for this behavior.
 
+The tracked iteration trace adds one more diagnosis target: `example_07_large_scale_routing_no_warm_start_seed43`. That seed now remains performance-only, and its blowup is concentrated in late iterations rather than the initial basin. In the current trace, seed `43` matches seed `42` through iteration `5`, then spends three extra iterations with `4` completed nets while `net_03` and `net_06` dominate both `nodes_expanded` and `congestion_check_calls`.
+
 Tracked metric keys:
 
 nodes_expanded, moves_generated, moves_added, pruned_closed_set, pruned_hard_collision, pruned_cost, route_iterations, nets_routed, nets_reached_target, warm_start_paths_built, warm_start_paths_used, refine_path_calls, timeout_events, iteration_reverify_calls, iteration_reverified_nets, iteration_conflicting_nets, iteration_conflict_edges, nets_carried_forward, score_component_calls, score_component_total_ns, path_cost_calls, danger_map_lookup_calls, danger_map_cache_hits, danger_map_cache_misses, danger_map_query_calls, danger_map_total_ns, move_cache_abs_hits, move_cache_abs_misses, move_cache_rel_hits, move_cache_rel_misses, guidance_match_moves, guidance_match_moves_straight, guidance_match_moves_bend90, guidance_match_moves_sbend, guidance_bonus_applied, guidance_bonus_applied_straight, guidance_bonus_applied_bend90, guidance_bonus_applied_sbend, static_safe_cache_hits, hard_collision_cache_hits, congestion_cache_hits, congestion_cache_misses, congestion_presence_cache_hits, congestion_presence_cache_misses, congestion_presence_skips, congestion_candidate_precheck_hits, congestion_candidate_precheck_misses, congestion_candidate_precheck_skips, congestion_grid_net_cache_hits, congestion_grid_net_cache_misses, congestion_grid_span_cache_hits, congestion_grid_span_cache_misses, congestion_candidate_nets, congestion_net_envelope_cache_hits, congestion_net_envelope_cache_misses, dynamic_path_objects_added, dynamic_path_objects_removed, dynamic_tree_rebuilds, dynamic_grid_rebuilds, static_tree_rebuilds, static_raw_tree_rebuilds, static_net_tree_rebuilds, visibility_corner_index_builds, visibility_builds, visibility_corner_pairs_checked, visibility_corner_queries_exact, visibility_corner_hits_exact, visibility_point_queries, visibility_point_cache_hits, visibility_point_cache_misses, visibility_tangent_candidate_scans, visibility_tangent_candidate_corner_checks, visibility_tangent_candidate_ray_tests, ray_cast_calls, ray_cast_calls_straight_static, ray_cast_calls_expand_snap, ray_cast_calls_expand_forward, ray_cast_calls_visibility_build, ray_cast_calls_visibility_query, ray_cast_calls_visibility_tangent, ray_cast_calls_other, ray_cast_candidate_bounds, ray_cast_exact_geometry_checks, congestion_check_calls, congestion_lazy_resolutions, congestion_lazy_requeues, congestion_candidate_ids, congestion_exact_pair_checks, verify_path_report_calls, verify_static_buffer_ops, verify_dynamic_candidate_nets, verify_dynamic_exact_pair_checks, refinement_windows_considered, refinement_static_bounds_checked, refinement_dynamic_bounds_checked, refinement_candidate_side_extents, refinement_candidates_built, refinement_candidates_verified, refinement_candidates_accepted, pair_local_search_pairs_considered, pair_local_search_attempts, pair_local_search_accepts, pair_local_search_nodes_expanded