---
license: apache-2.0
library_name: synthefy-nori
pipeline_tag: tabular-regression
tags:
  - tabular
  - tabular-regression
  - tabular-foundation-model
  - in-context-learning
  - synthetic-data
  - pytorch
---

<p align="center">
  <img src="synthefy_nori_banner.png" alt="Nori" width="100%">
</p>

# Nori

**Nori** is a tabular foundation model for **regression** via in-context
learning (ICL). Given a few labeled rows as context, it predicts on new query rows in a
**single forward pass**, with no task-specific training or fine-tuning. The model is
trained **entirely on synthetic data**.

- **Documentation:** https://docs.synthefy.com/nori/
- **Repository:** https://github.com/Synthefy/synthefy-nori
- **Library:** `pip install synthefy-nori`
- **Checkpoint:** `nori.pt` (this repo)
- **Parameters:** ~5.9M
- **License:** Apache-2.0

## Results

Mean and median R² of the base model across 96 regression tasks from three
public benchmark suites (single H200, up to 50K context rows per dataset):

| Suite | Datasets | Mean R² | Median R² |
|-------|---------:|--------:|----------:|
| TabArena | 13 | 0.8117 | 0.8757 |
| TALENT | 72 | 0.7569 | 0.8802 |
| OpenML | 11 | 0.6373 | 0.5856 |
| **Overall** | **96** | **0.7506** | **0.8702** |

Large-N / long-context tables (common in TabArena) are the current focus of the
large-table training stages. These numbers are reproducible end-to-end with one
command — see [Reproducing these numbers](https://github.com/Synthefy/synthefy-nori#reproducing-these-numbers).

> **Thinking** is an inference-time reasoning extension that improves these
> numbers further. Details are forthcoming.

## Usage

```bash
pip install synthefy-nori
```

```python
from sklearn.datasets import load_diabetes
from sklearn.model_selection import train_test_split
from synthefy_nori import NoriRegressor

X, y = load_diabetes(return_X_y=True)
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=0)

model = NoriRegressor()    # downloads these weights from the Hub on first use
model.fit(X_train, y_train)           # "fit" just stores the labeled rows as context
pred = model.predict(X_test)          # predictions in a single forward pass, no training
```

It uses a GPU when one is available and falls back to CPU. A one-shot helper skips the
object entirely:

```python
from synthefy_nori import predict
pred = predict(X_train, y_train, X_test, task="regression")
```

`predict` follows the `TabPFNRegressor.predict` contract: pass `output_type="mean"`
(default), `"median"`, or `"mode"` to choose the point estimate drawn from the model's
predictive distribution.

To run from a local checkpoint instead of the Hub default, pass a path:

```python
model = NoriRegressor(model_path="path/to/checkpoint.pt")
```

This checkpoint is **public**: the first inference call downloads and caches it
automatically, with no token and no access request. A Hugging Face token (read scope)
is only worth setting if you hit anonymous download rate limits — provide it via
`export HF_TOKEN=hf_...`, `hf auth login`, or `NoriRegressor(token="hf_...")`.

## How it works

### Architecture

A **FeaturesTransformer (~5.9M parameters)** that alternates two kinds of attention:

- **Feature attention** learns relationships between columns.
- **Sample attention** learns relationships between rows (context and query).
- **In-context learning**: predictions condition on labeled context rows, with no
  gradient updates at inference.

Key config: 16 transformer layers, embed_dim 128, hidden 384, 2 heads, the **v2-lite**
block (SwiGLU + RMSNorm + pre-norm), features grouped in pairs (`features_per_group=2`),
with **column-specific y-aware** feature attention. Features are encoded with RBF
embeddings; missing values are handled natively via learned mask embeddings. The
regression head predicts a full distribution over 999 quantiles (pinball loss).

### Synthetic data

The model never sees real data during training. Its capability comes from a diverse
synthetic data generator covering real-world tabular regimes:

- **Structural Causal Models (SCM)**: hierarchical DAGs with 8 edge-function types
  (MLP, decision tree, piecewise-linear, polynomial, periodic, RBF, log/exp, conv1d).
- **Regression priors**: 9 target families (dense/sparse linear, GAM, interactions,
  random MLP, random tree, radial/RBF, Fourier features, chained trigonometric).
- **Realism augmentations**: discretized features, noise features, correlated blocks,
  structural missingness, label noise.
- **Learnability filter**: an ExtraTrees signal-quality filter rejects unlearnable
  datasets so training compute is spent on learnable tasks.

Training runs entirely on synthetic data and **trains to completion** — there is no
real-data validation in the loop, so no benchmark data is needed to train and no eval
signal influences checkpoint selection. See the
[training guide](https://github.com/Synthefy/synthefy-nori/blob/main/docs/training.md)
for the full curriculum recipe.

## Intended use & limitations

- **Intended for** small-to-medium tabular regression where in-context learning is
  attractive (no per-task training).
- **Limitations:** the current gap vs the best baselines is on **large-N / long-context**
  TabArena datasets; dense O(N²) sample attention bounds practical context size. Very large
  tables are the focus of the large-table training stages.

## Citation

```bibtex
@software{synthefy_nori_2026,
  title  = {Nori: A Tabular Foundation Model Trained on Synthetic Data},
  author = {Synthefy},
  year   = {2026},
  url    = {https://github.com/Synthefy/synthefy-nori}
}
```

## License

Apache-2.0. See
[LICENSE](https://github.com/Synthefy/synthefy-nori/blob/main/LICENSE) and
[NOTICE](https://github.com/Synthefy/synthefy-nori/blob/main/NOTICE).