---
title: KakeyaLattice KV-cache compression
emoji: 📐
colorFrom: indigo
colorTo: purple
sdk: docker
app_port: 7860
pinned: false
license: apache-2.0
---
 
# KakeyaLattice KV-cache compression demo
 
Side-by-side comparison of **bf16 DynamicCache** vs **KakeyaLattice E8**
compression at three quality levels (Q=10 aggressive, Q=38 balanced,
Q=152 near-lossless) on a small HuggingFace causal LM.
 
Default model: `Qwen/Qwen2-0.5B` (head_dim=64, E8-compatible, runs on
free CPU tier). Override `KAKEYA_DEMO_MODEL` env var to use a larger
model on a GPU Space.
 
## How it works
 
`KakeyaLatticeCache` is a drop-in subclass of `transformers.DynamicCache`
that applies a Zamir-Feder nested-lattice codec roundtrip (encode +
decode) to every K and V written into the cache.
 
```python
from transformers import AutoModelForCausalLM
from kakeyalattice.hf import KakeyaLatticeCache
 
model = AutoModelForCausalLM.from_pretrained("Qwen/Qwen2-0.5B")
cache = KakeyaLatticeCache(
    variant="e8", q_range=38,
    num_hidden_layers=model.config.num_hidden_layers,
    head_dim=model.config.head_dim,
)
out = model.generate(input_ids, max_new_tokens=200, past_key_values=cache)
```
 
## What you'll see in the demo
 
For each prompt, the app generates four times:
 
| config | bits/token | expected quality |
| --- | --- | --- |
| bf16 DynamicCache | 1024 (reference) | identical to reference |
| E8 Q=152 near-lossless | ~960 (-6%) | essentially identical |
| E8 Q=38 balanced | ~440 (-57%) | ~1% deviation in ppl |
| E8 Q=10 aggressive | ~320 (-69%) | noticeably different but coherent |
 
## Caveats
 
1. The cache **roundtrips** K/V but stores the reconstructed tensor in
   the model's KV dtype. Real HBM bytes saved are **nominal**.
2. Decode is ~1.3-2× slower than bf16 because the codec runs as pure
   PyTorch ops.
3. Head-dim must be a power of 2 and divisible by 4 (D4) or 8 (E8).
 
## Links
 
- Package: https://pypi.org/project/kakeyalattice/
- Repo: https://github.com/FluffyAIcode/LLM-KV--Cache-compress
- Paper: [reports/paper/](https://github.com/FluffyAIcode/LLM-KV--Cache-compress/tree/main/reports/paper)