---
language: en
tags:
  - semantic-ids
  - recommendation
  - generative-retrieval
  - qwen3
  - fine-tuned
license: apache-2.0
base_model: Qwen/Qwen3-1.7B
datasets:
  - amazon-pet-supplies
---

# Qwen3-1.8B Fine-tuned for Semantic ID Recommendation

## Overview

Qwen3-1.8B fine-tuned for generative product recommendation via hierarchical semantic identifiers. The model generates 4-level Semantic IDs (`<|sid_start|><|A#|><|B#|><|C#|><|D#|><|sid_end|>`) given product descriptions, purchase histories, or co-purchase contexts.

This is the smaller model in a controlled comparison experiment (1.8B vs 8B) conducted under identical training conditions.

## Training

### Stage 1: Vocabulary Expansion
- Added 1,027 special tokens (3 structural + 4×256 codebook tokens)
- Trained only embedding matrices (0.3% of parameters)
- 2,000 steps, LR 1×10⁻³, batch 64

### Stage 2: Full Fine-tuning
- **Dataset**: 4,719,994 instruction-formatted conversations (Amazon Pet Supplies)
- **Task types**: text→SID, sequential recommendation, co-purchase prediction
- **Optimizer**: AdamW 8-bit, LR 2×10⁻⁵, cosine with min LR (0.2×peak)
- **Warmup**: 3%, weight decay 0.01
- **Batch**: 64 × 2 = 128 effective, 3 epochs
- **Techniques**: Custom instruction masking, greedy sequence packing (~3× throughput)
- **Hardware**: NVIDIA H100 80GB (vast.ai)

## Results

Hierarchical SID prediction accuracy (A-level match, greedy decoding):

| Task | Accuracy |
|------|----------|
| Text → SID | 59.9% |
| Sequential recommendation | 7.0% |
| Co-purchase prediction | 5.5% |

Evaluation: 3,000 samples per task, 11 task types.

## Usage

```python
from transformers import AutoModelForCausalLM, AutoTokenizer

model = AutoModelForCausalLM.from_pretrained("kalistratov/qwen3-1.8b-semantic-ids")
tokenizer = AutoTokenizer.from_pretrained("kalistratov/qwen3-1.8b-semantic-ids")
```

## Citation

Master's thesis, Moscow Institute of Physics and Technology (MIPT), 2026.

## References

1. Y. Sun et al. "OpenOneRec," arXiv:2502.18851, 2025.
2. J. Liu et al. "PLUM," arXiv:2406.12346, 2024.
3. E. Yan. "semantic-ids-llm," GitHub, 2024.