# Agent 152: MAMBA-2 Model Dtype Fix (F32→F64)

**Status**: ✅ COMPLETE

**Mission**: Fix model initialization to use F64 instead of F32 for VarBuilder and Tensor operations

**Time**: 5 minutes

---

## Changes Made

Fixed all `DType::F32` references to `DType::F64` in `/home/jgrusewski/Work/foxhunt/ml/src/mamba/mod.rs`:

### Locations Fixed (6 instances):

1. **Line 228**: `Tensor::zeros` for hidden state creation
   - `DType::F32` → `DType::F64`

2. **Line 257**: `Tensor::ones` for delta tensor
   - `DType::F32` → `DType::F64`

3. **Line 265**: `Tensor::zeros` for SSM hidden state
   - `DType::F32` → `DType::F64`

4. **Line 428**: `VarBuilder::from_varmap` initialization
   - `DType::F32` → `DType::F64`

5. **Line 662**: `Tensor::eye` for identity matrix in `discretize_ssm`
   - `DType::F32` → `DType::F64`

6. **Line 1096**: `Tensor::eye` for identity matrix in `discretize_ssm_with_gradients`
   - `DType::F32` → `DType::F64`

---

## Additional Fixes Found

During review, found that Agent 147/151 had already fixed:
- Line 656-657: `discretize_ssm` now uses F64 directly (no F32 conversion)
- Line 683-684: `discretize_ssm_input` now uses F64 directly
- Line 949: `loss.to_scalar::<f64>()` (correct dtype)
- Line 1089-1090: `discretize_ssm_with_gradients` uses F64 directly
- Line 1123-1124: `discretize_ssm_input_with_gradients` uses F64 directly

---

## Impact

**Root Cause Fixed**: Model initialization now consistently uses F64 precision throughout, matching the output of `mean_all()` and avoiding dtype mismatches.

**Expected Result**:
- No more "incompatible dtype" errors during model training
- Consistent F64 precision across all SSM state matrices
- Proper gradient flow without dtype conversion issues

---

## Files Modified

- `/home/jgrusewski/Work/foxhunt/ml/src/mamba/mod.rs` (6 changes)

---

## Testing Required

**No compilation performed** (per resource constraint).

**Recommended Validation**:
```bash
cargo check -p ml
cargo test -p ml --test mamba_tests
```

---

## Next Steps

1. Compile `ml` crate to verify no dtype errors
2. Run MAMBA-2 unit tests
3. Validate model initialization succeeds with F64 precision
4. Test training loop with gradient computations

---

**Agent 152 Complete** - MAMBA-2 dtype consistency achieved (F32→F64)