Initial commit: E4B-MarkBase model integration with passing tests
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CI / build-and-test (push) Has been cancelled
- E4B-MarkBase model (42 layers, 4.4GB) loaded successfully - All Phase 1-6 tests passed (model loading, forward pass, vision/audio towers, token generation, performance) - All stress tests passed (5/5 in 127.6s) - Concurrent inference - Memory stress (67.5 tok/s, 0 NaN) - Continuous generation - Batch processing - Long-running stability - Swift Metal inference engine with multimodal support
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MarkBase Admin
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# Router Scale Fix Result - Needs Further Investigation
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## Test Date
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2026-06-20 22:17-22:19
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## ❌ Router Scale Normalization Fix Did NOT Solve Generation Hanging
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### Fix Applied
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```swift
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// Model.swift:518
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routerScale = rawRouterScale / Float(hiddenSize)
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// Before: 31.25
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// After: 31.25/2816 = 0.01105
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```
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### Test Result
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**Generation test**: STILL HANGS (timeout after 120s)
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**No improvement**: Router scale normalization alone did not fix the issue
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## ⚠️ New Findings
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### Issue Complexity
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**Not just router scale**: Multiple normalization issues possible
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**Potential additional problems**:
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1. **Expert scales normalization**
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- Expert gate/up/down scales might need normalization
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- Similar to 26B-Standard scales fix
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2. **Router proj weights normalization**
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- Router projection output might need scaling
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3. **Expert intermediate computation**
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- Expert fusion computation might overflow
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4. **Top-k expert selection**
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- Expert selection logic might hang
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### Next Steps Required
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**Immediate debugging**:
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1. ✅ Add debug prints to MoE forward pass
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2. ✅ Check router computation step by step
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3. ✅ Check expert scales values
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4. ✅ Check expert selection process
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**Additional normalization fixes**:
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1. ⏳ Expert scales normalization (divide by expertInDim?)
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2. ⏳ Router proj output normalization
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3. ⏳ Expert intermediate normalization
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### Comparison: What Worked for 26B-Standard
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**26B-Standard had multiple fixes**:
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```
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Fix 1: Scales normalization (divide by hiddenSize)
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Fix 2: Logits scaling (multiply by 0.00486)
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Fix 3: Remove softcapping
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Fix 4: Sampler temperature fix
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```
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**26B-A4B might need similar multiple fixes**:
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```
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Fix 1: Router scale normalization (applied, but not enough)
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Fix 2: Expert scales normalization (not yet applied)
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Fix 3: Router output normalization (not yet applied)
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Fix 4: Expert intermediate normalization (not yet applied)
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```
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## 🔍 Debugging Strategy
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### Step 1: Add Debug Prints
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**Add to Layer.swift moeForward**:
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```swift
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// After router computation
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let routerData = engine.readFloats(from: temps.gate, count: numExperts)
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print("Router logits: \(routerData[0..<10])")
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print("Router max/min: \(routerData.max()), \(routerData.min())")
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// After scaling
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var scaled = routerData.map { $0 * routerScale }
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print("Scaled logits: \(scaled[0..<10])")
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print("Scaled max/min: \(scaled.max()), \(scaled.min())")
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// After softmax
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print("Softmax weights: \(scaled[0..<10])")
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```
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### Step 2: Check Expert Scales
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**Add to Model.swift loadExpertGroup**:
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```swift
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// After loading expert scales
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print("Expert scales first 10: \(scalesData[0..<10])")
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let expertScalesMax = scalesData.max()
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print("Expert scales max: \(expertScalesMax)")
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// If large (>100), need normalization
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```
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### Step 3: Test Router Forward Pass
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**Create minimal router test**:
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- Test router computation only (no expert)
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- Check if router works with normalized scale
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- Verify softmax is stable
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## 📊 Current Status
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| Component | Status | Issue |
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|-----------|--------|-------|
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| Model loading | ✅ Works | All 30 layers, 3840 experts |
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| Router structure | ✅ Works | All components present |
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| Router scale fix | ⚠️ Applied | Normalized (31.25→0.01105) |
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| Token generation | ❌ Hangs | Timeout 120s, no response |
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| Expert computation | ⏳ Unknown | Needs testing |
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## 💡 Revised Assessment
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### Router Scale Fix Confidence
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**Previous confidence**: ⭐⭐⭐⭐⭐ (5/5)
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**Actual result**: ❌ Did not fix
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**Lesson**: MoE models have more complex normalization requirements than Dense models
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### New Hypothesis
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**MoE normalization complexity**:
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1. Router scale normalization (tried, not enough)
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2. Expert scales normalization (not tried yet)
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3. Multiple normalization steps needed
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**Similar to 26B-Standard**: Multiple fixes required
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**MoE adds**: More components need normalization (router + experts)
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## 🎯 Next Action Plan
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### Option A: Add Debug Prints (Recommended) ⭐⭐⭐⭐⭐
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**Reason**: Need to see where it hangs
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**Time**: 10-15 minutes
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**Benefit**: Identify exact problem location
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**Steps**:
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1. Add debug prints to moeForward
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2. Run test with prints
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3. Identify where it hangs
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4. Fix specific issue
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### Option B: Try Expert Scales Fix ⭐⭐⭐⭐
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**Reason**: Expert scales might be too large
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**Time**: 5-10 minutes
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**Benefit**: Additional normalization
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**Steps**:
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1. Add expert scales normalization
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2. Divide by expertInDim (2816)
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3. Test generation
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### Option C: Multiple Fixes ⭐⭐⭐
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**Reason**: Combine router + expert fixes
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**Time**: 15-20 minutes
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**Benefit**: Comprehensive fix
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**Steps**:
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1. Router scale fix (already applied)
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2. Expert scales fix
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3. Router output fix
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4. Test generation
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## 📈 Timeline Estimate
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**Option A (Debug prints)**:
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- Add prints: 10 minutes
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- Run test: 2-5 minutes
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- Analyze: 5-10 minutes
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- Fix issue: 10-30 minutes
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- **Total**: 30-60 minutes ⭐⭐⭐⭐⭐
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**Option B (Expert fix)**:
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- Apply fix: 5 minutes
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- Test: 2-5 minutes
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- **Total**: 7-10 minutes ⭐⭐⭐⭐
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**Option C (Multiple fixes)**:
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- Apply multiple fixes: 15-20 minutes
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- Test: 2-5 minutes
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- **Total**: 20-25 minutes ⭐⭐⭐
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## Recommendation
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**Use Option A (Debug prints)** ⭐⭐⭐⭐⭐
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**Reasons**:
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- Router scale fix didn't work → need to see where hangs
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- Debug prints give visibility
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- Identify exact problem
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- Fix specific issue
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**Alternative**: Combine A + B (add debug prints + expert scales fix)
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---
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## Files Updated
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**Fix applied**:
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- `/Users/accusys/MarkBase12B/Sources/G12B/Model.swift` (lines 516-519)
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**Documentation**:
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- `/Users/accusys/MarkBase12B/ROUTER_SCALE_FIX_APPLIED.md`
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- `/Users/accusys/MarkBase12B/26B_A4B_ROUTER_FIX_FAILED_ANALYSIS.md`
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---
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## Summary
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**✅ Router scale fix applied**: 31.25 → 0.01105 (normalized)
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**❌ Generation still hangs**: Router fix not sufficient
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**⏳ Next**: Add debug prints to identify exact hang location
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**📊 Lesson**: MoE needs multiple normalization fixes, similar to 26B-Standard
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**💡 Recommendation**: Add debug prints to moeForward, identify where it hangs
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