---
tags:
  - pytorch
  - safetensors
license: mit
---

# dm_qwen4b_noise_emulator

Laplacian kernel regression noise model for `std_math` prediction in data mixture optimization.

Predicts per-configuration std_math (across seeds) given data mixture proportions,
used as a heteroscedastic noise model in Bayesian optimization.

## Architecture

- Kernel: Laplacian  `K(x, x') = exp(-γ · ||x - x'||₁)`
- Support points: 50 training configs
- Input features (3): `[if_prop1, math_prop1, math_prop2]`  (values in [0, 1])
- Output: predicted std_math (scalar)

## Usage

```python
import torch
from huggingface_hub import hf_hub_download
from safetensors.torch import load_file


class KernelRegressionModel(torch.nn.Module):
    def __init__(self, dual_coef, X_fit, gamma=0.1):
        super().__init__()
        self.gamma = gamma
        self.register_buffer("dual_coef", dual_coef)
        self.register_buffer("X_fit", X_fit)

    def forward(self, x):
        dist = torch.cdist(x, self.X_fit, p=1)
        K = torch.exp(-self.gamma * dist)
        return K @ self.dual_coef


path = hf_hub_download("chewwt/dm_qwen4b_noise_emulator", "noise_model.safetensors")
tensors = load_file(path)
model = KernelRegressionModel(tensors["dual_coef"], tensors["X_fit"])
model.eval()

# x: (batch, 3) float64 tensor, features in [0, 1]
x = torch.tensor([[0.3, 0.4, 0.2]], dtype=torch.float64)
with torch.no_grad():
    sigma = model(x)   # predicted std_math
```