docs: calibration session handover — H1-H5 hypotheses, Cronbach α, full protocol 5 testable hypotheses: H1: BF16 truncation flips ~5% of ranks (bucket boundary effect) H2: γ+φ encoding preserves more rank order than linear CDF H3: i8 signed > u8 unsigned for gate-heavy roles specifically H4: ICC profile correction brings ALL encoding paths to ρ > 0.998 H5: Cronbach α reveals which tasks need multi-lens vs single lens Testing protocol: Phase 1: ONNX f32 ground truth (rten, Jina v5, 1000 pairs) Phase 2: BF16 baseline (stream GGUF, same CLAM) Phase 3: 5 encoding paths (linear, γ+φ, i8, γ+φ signed, spiral) Phase 4: Spearman ρ before/after ICC per path Phase 5: Cronbach α across 6 lenses Synthesis matrix: which encoding × which role × ICC or not. Estimated: 3-4 hours. Validates everything built in 67+ commits. https://claude.ai/code/session_01ChLvBfpJS8dQhHxRD4pYNp

.claude/HANDOVER_CALIBRATION_SESSION.md

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+# SESSION HANDOVER: Calibration, Encoding & Cronbach Alpha Validation
+
+## HYPOTHESIS
+
+The thinking engine's distance tables are a MEASUREMENT INSTRUMENT.
+Like any instrument, they need validity testing before the measurements
+mean anything. The hypothesis chain:
+
+### H1: BF16 truncation causes systematic rank flips
+```
+TEST: For 10,000 centroid pairs:
+  Compute cos from ONNX f32 weights → rank order R_f32
+  Compute cos from GGUF BF16 weights → rank order R_bf16
+  Count rank disagreements where |cos_f32| < 0.008 (BF16 uncertainty zone)
+
+PREDICT: ~5% of pairs within ±0.008 of bucket boundaries flip rank.
+MEASURE: Spearman ρ(R_f32, R_bf16) < 1.0 by exactly this amount.
+VALIDATE: If ρ matches prediction → we understand the truncation physics.
+```
+
+### H2: γ+φ encoding preserves more rank order than linear CDF
+```
+TEST: Same 10,000 pairs:
+  Encode cos → u8 via linear CDF → rank order R_linear
+  Encode cos → u8 via γ+φ redistribution → rank order R_gamma
+
+PREDICT: ρ(R_f32, R_gamma) > ρ(R_f32, R_linear)
+  because γ concentrates resolution near the gate decision boundary
+  where BF16 truncation causes the most rank flips.
+VALIDATE: If γ+φ > linear → golden ratio redistribution IS calibration.
+```
+
+### H3: i8 signed preserves more information than u8 unsigned for gate-heavy roles
+```
+TEST: For ffn_gate role specifically:
+  Encode cos → u8[0,255] → Spearman vs f32 → ρ_unsigned
+  Encode cos → i8[-128,+127] → Spearman vs f32 → ρ_signed
+
+PREDICT: ρ_signed > ρ_unsigned for gate (68.9% near zero, sign matters)
+  ρ_signed ≈ ρ_unsigned for Q (positive-skewed, sign rarely matters)
+VALIDATE: If gate benefits but Q doesn't → sign preservation is role-specific.
+```
+
+### H4: ICC profile correction brings ALL encoding paths to ρ > 0.998
+```
+TEST: After ICC correction on each path:
+  ρ(R_f32, R_corrected_linear) > 0.998
+  ρ(R_f32, R_corrected_gamma) > 0.998
+  ρ(R_f32, R_corrected_signed) > 0.998
+
+PREDICT: ICC correction absorbs the residual error regardless of encoding path.
+  The CHEAPEST encoding + ICC ≈ the BEST encoding without ICC.
+VALIDATE: If all paths reach 0.998 after ICC → encoding choice doesn't matter,
+  only the ICC quality matters. Simplify to cheapest encoding + good ICC.
+```
+
+### H5: Multi-lens Cronbach alpha shows internal consistency
+```
+TEST: For N sentence pairs, compute distances via all 6 lenses.
+  Each lens = one "item" in the psychometric instrument.
+  Cronbach α = internal consistency of the multi-lens measurement.
+
+PREDICT: α > 0.90 for similar-pair detection (all lenses agree on "similar")
+  α < 0.70 for relevance detection (lenses disagree = DIFFERENT information)
+VALIDATE: High α for similarity = lenses are redundant (use one, save compute).
+  Low α for relevance = lenses are complementary (use all, superposition helps).
+```
+
+---
+
+## TESTING PROTOCOL
+
+### Phase 1: Ground Truth (ONNX f32)
+
+```python
+# Load Jina v5 ONNX via rten
+import rten  # or: use burn, or: use candle
+
+model = rten.load("model.onnx", "model.onnx_data")
+tokenizer = load_tokenizer("tokenizer.json")
+
+# Generate ground truth for 1000 sentence pairs
+pairs = load_test_pairs()  # diverse: similar, dissimilar, related, unrelated
+f32_cosines = []
+for a, b in pairs:
+    emb_a = model.forward(tokenizer.encode(a))  # f32 embedding
+    emb_b = model.forward(tokenizer.encode(b))
+    f32_cosines.append(cosine(emb_a, emb_b))
+
+# This is the RAW. Everything calibrates against this.
+```
+
+### Phase 2: BF16 Baseline
+
+```python
+# Stream Jina v5 F16 GGUF
+bf16_weights = stream_gguf("v5-small-text-matching-F16.gguf", "token_embd.weight")
+
+# Same CLAM centroids, but from BF16
+bf16_centroids = clam_sample(bf16_weights, n=256)
+bf16_table = build_cosine_table(bf16_centroids)  # f32 cosine on bf16 inputs
+
+# Map same sentences through BF16-derived codebook
+bf16_distances = []
+for a, b in pairs:
+    ca = codebook_lookup(tokenizer.encode(a), bf16_assignments)
+    cb = codebook_lookup(tokenizer.encode(b), bf16_assignments)
+    bf16_distances.append(bf16_table[ca][cb])
+```
+
+### Phase 3: Encoding Paths
+
+```rust
+// For each encoding path, produce a u8/i8 distance table:
+
+// Path 1: Linear CDF (current HDR encoding)
+let linear_table = hdr_cdf_encode(&raw_cosines, 256);  // u8[0,255]
+
+// Path 2: γ+φ redistributed
+let gamma_table = gamma_phi_encode(&raw_cosines, gamma=1.50, 256);
+
+// Path 3: Signed i8
+let signed_table = signed_encode(&raw_cosines, 256);  // i8[-128,+127]
+
+// Path 4: γ+φ signed
+let gamma_signed_table = gamma_phi_signed_encode(&raw_cosines, gamma=1.50, 256);
+
+// Path 5: highheelbgz spiral
+let spiral_table = spiral_encode(&raw_cosines, stride=golden_ratio, 256);
+```
+
+### Phase 4: Spearman ρ per path
+
+```rust
+fn evaluate_path(f32_cosines: &[f32], encoded_table: &[u8], assignments: &[u16], pairs: &[(Text, Text)]) -> f32 {
+    let encoded_distances: Vec<f32> = pairs.iter()
+        .map(|(a, b)| {
+            let ca = assignments[tokenize(a)];
+            let cb = assignments[tokenize(b)];
+            encoded_table[ca * N + cb] as f32
+        })
+        .collect();
+
+    spearman(&f32_cosines, &encoded_distances)
+}
+
+// Measure BEFORE ICC:
+let rho_linear  = evaluate_path(&f32_cosines, &linear_table, ...);
+let rho_gamma   = evaluate_path(&f32_cosines, &gamma_table, ...);
+let rho_signed  = evaluate_path(&f32_cosines, &signed_table, ...);
+let rho_spiral  = evaluate_path(&f32_cosines, &spiral_table, ...);
+
+// Build ICC profiles:
+let icc_linear  = LensProfile::build("jina-v5", "token_embd", Linear, &f32_cosines, &linear_table, N);
+let icc_gamma   = LensProfile::build("jina-v5", "token_embd", GammaPhi, &f32_cosines, &gamma_table, N);
+
+// Measure AFTER ICC:
+let rho_linear_corrected  = evaluate_corrected(&f32_cosines, &linear_table, &icc_linear, ...);
+let rho_gamma_corrected   = evaluate_corrected(&f32_cosines, &gamma_table, &icc_gamma, ...);
+```
+
+### Phase 5: Cronbach Alpha
+
+```rust
+/// Cronbach's alpha for multi-lens internal consistency.
+///
+/// items[lens][pair] = distance measured by this lens for this pair.
+/// Higher α = more agreement between lenses.
+fn cronbach_alpha(items: &[Vec<f32>]) -> f32 {
+    let k = items.len() as f32;  // number of lenses
+    let n = items[0].len();       // number of pairs
+
+    // Total score variance
+    let totals: Vec<f32> = (0..n)
+        .map(|pair| items.iter().map(|lens| lens[pair]).sum::<f32>())
+        .collect();
+    let var_total = variance(&totals);
+
+    // Sum of item variances
+    let var_sum: f32 = items.iter()
+        .map(|lens| variance(lens))
+        .sum();
+
+    // α = (k / (k-1)) × (1 - Σvar_item / var_total)
+    (k / (k - 1.0)) * (1.0 - var_sum / var_total)
+}
+
+fn variance(data: &[f32]) -> f32 {
+    let n = data.len() as f32;
+    let mean = data.iter().sum::<f32>() / n;
+    data.iter().map(|x| (x - mean).powi(2)).sum::<f32>() / n
+}
+
+// Measure:
+let lens_distances = vec![
+    jina_distances,      // lens 0
+    bge_distances,       // lens 1
+    reranker_distances,  // lens 2
+    reader_distances,    // lens 3
+    qwopus_distances,    // lens 4
+];
+
+let alpha = cronbach_alpha(&lens_distances);
+// α > 0.90: lenses are redundant (one is enough for this task)
+// α 0.70-0.90: lenses agree mostly (superposition adds a little)
+// α < 0.70: lenses see different things (superposition is valuable)
+```
+
+---
+
+## SYNTHESIS: What the Results Tell Us
+
+### If H1 confirms (BF16 flips ~5% of ranks):
+→ boundary_risk metadata is ESSENTIAL
+→ 95/5 split: fast cascade for safe pairs, LEAF validation for boundary pairs
+→ γ+φ should reduce the 5% by moving boundaries away from BF16 quant steps
+
+### If H2 confirms (γ+φ > linear):
+→ γ+φ becomes the DEFAULT encoding (not optional, mandatory)
+→ Per-role γ offsets are critical (Gate=1.50, Q=0.37)
+→ The golden ratio IS the calibration (not a cosmetic choice)
+
+### If H3 confirms (i8 > u8 for gate, ≈ for Q):
+→ i8 for gate-modulated roles (K, V, Up), u8 for extern roles (Q, Down)
+→ Mixed encoding per role within the same layer
+→ SiLU-ONNX is definitively unnecessary
+
+### If H4 confirms (ICC brings all to 0.998):
+→ Encoding choice is secondary to ICC quality
+→ Cheapest encoding + good ICC = optimal
+→ Focus engineering effort on ICC, not on better encodings
+
+### If H5 shows high Cronbach α for similarity:
+→ Multi-lens superposition is REDUNDANT for similarity tasks
+→ Use ONE lens (cheapest) for similarity, save 5× compute
+→ Reserve multi-lens for tasks where α < 0.70 (complementary lenses)
+
+### If H5 shows low Cronbach α for relevance:
+→ Multi-lens superposition IS VALUABLE for relevance tasks
+→ Embedding (Jina) sees different things than reranker
+→ The DISAGREEMENT between lenses IS information
+→ Keep all lenses, the superposition product captures what no single lens sees
+
+---
+
+## CODE LOCATIONS
+
+```
+Contract DTOs:
+  crates/lance-graph-contract/src/high_heel.rs
+    → LensProfile (ICC profile DTO)
+    → LensConfig (6-lane registry)
+    → EncodingPath enum
+    → LENS_REGISTRY static array
+
+Thinking Engine:
+  crates/thinking-engine/src/jina_lens.rs     (Jina v3 lens, 250K vocab)
+  crates/thinking-engine/src/bge_m3_lens.rs   (BGE-M3 lens, 250K vocab)
+  crates/thinking-engine/src/reranker_lens.rs  (Reranker v3, 151K vocab, NEW)
+  crates/thinking-engine/src/silu_correction.rs (may be replaced by i8)
+  crates/thinking-engine/src/engine.rs         (MatVec cycle)
+
+Calibration:
+  crates/thinking-engine/examples/calibrate_lenses.rs  (Spearman + ICC harness)
+  crates/thinking-engine/examples/hdr_audit.rs         (all models compared)
+  crates/thinking-engine/examples/silu_crosscheck.rs   (u8 vs corrected)
+
+Codec:
+  crates/bgz-tensor/src/gamma_phi.rs          (γ+φ encode/decode)
+  crates/bgz-tensor/src/codebook_calibrated.rs (two-pass build)
+  crates/highheelbgz/src/                      (spiral stride, golden ratio)
+
+ONNX:
+  AdaWorldAPI/rten                             (ONNX runtime, your fork)
+  AdaWorldAPI/rten-ndarray-demo                (rten ↔ ndarray bridge)
+
+Ground Truth Models:
+  jinaai/jina-embeddings-v5-text-small-text-matching
+    → model.onnx + model.onnx_data (2.4 GB, f32 precision)
+    → v5-small-text-matching-F16.gguf (1.2 GB, streamable)
+    → tokenizer.json (11.4 MB, real BPE)
+
+Data:
+  crates/thinking-engine/data/Qwopus3.5-27B-v3-BF16-silu/
+    → 64 layers × 5 role tables (305 binary files)
+    → 248K token assignments
+    → tokenizer.json (Qwen2 BPE)
+    → layer_stats.json
+  crates/thinking-engine/data/jina-v3-hdr/ (64 KB table + 488 KB index)
+  crates/thinking-engine/data/bge-m3-hdr/ (64 KB table + 488 KB index)
+  crates/thinking-engine/data/jina-reranker-v3-BF16-hdr/ (64 KB table + 296 KB index)
+  crates/thinking-engine/data/codebooks/ (8 models, 64×64 tables)
+```
+
+---
+
+## IMPLEMENTATION ORDER
+
+```
+1. Download Jina v5 ONNX (2.4 GB) + GGUF (1.2 GB) + tokenizer
+2. Load ONNX via rten → generate f32 ground truth for 1000 pairs
+3. Stream GGUF → CLAM → build 5 encoding variants
+4. Measure Spearman ρ for each (H1-H3)
+5. Build ICC profiles for each
+6. Measure corrected ρ (H4)
+7. Run all 6 lenses on same pairs → Cronbach α (H5)
+8. Synthesize: which encoding × which role × ICC or not
+9. Encode findings as LensProfile metadata in contract
+10. Re-bake tables with winning encoding per role
+
+Estimated: 3-4 hours for complete validation.
+```
+
+---
+
+## SESSION CONTEXT (what was built before this)
+
+```
+This session (session_01ChLvBfpJS8dQhHxRD4pYNp) delivered:
+  67+ commits across lance-graph + ndarray
+  235K LOC Rust across 18 crates
+
+Key deliverables:
+  - Qwopus 27B: 64 layers streamed from 53.8 GB BF16 in 116s
+  - SiLU gate correction: 86% material (BUT may be replaced by i8 signed)
+  - 4096-centroid codebook: 248K tokens
+  - Real Qwen BPE tokenizer
+  - Living thought loop (tension-driven autoregressive)
+  - MoE architecture (4096 experts, top-128)
+  - NARS gate modulator (three modes)
+  - Jina Reranker lens (wired, 9 tests)
+  - LensProfile ICC DTO
+  - LensConfig 6-lane registry
+  - Calibration harness (Spearman + ICC builder)
+  - OSINT pipeline (spider + OCR + NARS expansion)
+  - Wikileaks graph (1,872 nodes)
+  - SIMD OCR (10× faster than tesseract)
+  - Felt OCR (Base17/polar/palette)
+
+Parallel session doing:
+  - i8 signed tables (excitation/inhibition)
+  - u8 vs i8 dual-path comparison
+  - Started from reranker lens (this session wired it)
+
+This calibration session validates ALL of the above.
+Without it, every measurement drifts. GPS without relativity.
+```