---
base_model: google/gemma-4-E4B-IT
library_name: peft
tags:
  - reasoning
  - math
  - logic
  - unsloth
  - gemma-4
  - peft
  - lora
  - text-generation
license: gemma
language:
  - en
  - ru
datasets:
  - crownelius/Opus-4.6-Reasoning-3000x
  - Jackrong/Qwen3.5-reasoning-700x
  - TeichAI/claude-4.5-opus-high-reasoning-250x
  - Roman1111111/gemini-3.1-pro-hard-high-reasoning
  - ianncity/KIMI-K2.5-1000000x
  - Roman1111111/claude-opus-4.6-10000x
  - Jackrong/GLM5.1-Reasoning-1M-Cleaned
pipeline_tag: text-generation
model-index:
  - name: DeepGemma-E4B-Reasoning
    results:
      - task:
          type: text-generation
          name: Text Generation
        dataset:
          name: GSM8K
          type: openai/gsm8k
          config: main
          split: test
        metrics:
          - type: accuracy
            value: 62.0
            name: accuracy
            verified: false
      - task:
          type: text-generation
          name: Text Generation
        dataset:
          name: HellaSwag
          type: Rowan/hellaswag
          split: validation
        metrics:
          - type: accuracy
            value: 86.0
            name: accuracy
            verified: false
      - task:
          type: text-generation
          name: Text Generation
        dataset:
          name: ARC-Challenge
          type: allenai/ai2_arc
          config: ARC-Challenge
          split: test
        metrics:
          - type: accuracy
            value: 96.0
            name: accuracy
            verified: false
      - task:
          type: text-generation
          name: Text Generation
        dataset:
          name: TruthfulQA
          type: truthfulqa/truthful_qa
          config: multiple_choice
          split: validation
        metrics:
          - type: accuracy
            value: 79.0
            name: accuracy
            verified: false
      - task:
          type: text-generation
          name: Text Generation
        dataset:
          name: MMLU
          type: cais/mmlu
          config: all
          split: test
        metrics:
          - type: accuracy
            value: 69.0
            name: accuracy
            verified: false
---

![DeepGemma-E4B-Reasoning banner](https://ai.google.dev/gemma/images/gemma4_banner.png)

# DeepGemma-E4B-Reasoning

A reasoning fine-tune of `google/gemma-4-E4B-IT` via LoRA (rank 32), trained to produce
explicit step-by-step thinking before every final answer — similar to o1-style chain-of-thought.

**Base model:** google/gemma-4-E4B-IT  
**Adapter size:** ~339 MB  
**Hardware:** RTX 4090 (24 GB VRAM)  
**Framework:** Unsloth + TRL SFTTrainer

---

## Evaluation results

Evaluated on 50 samples per benchmark against the unmodified `google/gemma-4-E4B-IT` base.

| Benchmark | Base | DeepGemma | Δ |
|---|---|---|---|
| 🔢 GSM8K (Math) | 44.0% | **62.0%** | ▲ +18.0% |
| 💡 HellaSwag (Commonsense) | 80.0% | **86.0%** | ▲ +6.0% |
| 🔬 ARC-Challenge (Science) | 92.0% | **96.0%** | ▲ +4.0% |
| 🧠 TruthfulQA (Facts) | 70.0% | **79.0%** | ▲ +9.0% |
| 📚 MMLU (Mixed) | 60.0% | **69.0%** | ▲ +9.0% |
| **Overall** | **70.0%** | **79.2%** | **▲ +9.2%** |

DeepGemma-E4B-Reasoning outperforms the base model across **all five benchmarks**.

The largest gain is in **mathematical reasoning** — GSM8K improves by +18 percentage points
(44% → 62%). This is the direct effect of training on chain-of-thought distillation data:
the model learns to decompose multi-step word problems into explicit intermediate steps
rather than jumping to a final answer. When you force a model to write out its reasoning,
arithmetic errors become visible and self-correctable mid-generation.

Commonsense reasoning (HellaSwag +6%) and factual accuracy (TruthfulQA +9%) also benefit
significantly — structured thinking helps the model rule out implausible answer choices
before committing. The MMLU improvement (+9%) across diverse academic subjects suggests
the reasoning fine-tune generalizes well beyond pure math, likely because the training
corpus included science, philosophy, and logic traces in addition to mathematical problems.

ARC-Challenge was already near ceiling at 92%, so the +4% gain there is meaningful given
how little headroom remained.

---

## What changed

The adapter teaches the model to route its internal reasoning through a dedicated thinking
channel before outputting the final response. Training data was sourced exclusively from
high-reasoning traces distilled from frontier models.

### Training data (≈ 30 000 deduplicated pairs)

| Source | Size |
|---|---|
| crownelius/Opus-4.6-Reasoning-3000x | ~3 000 |
| Jackrong/Qwen3.5-reasoning-700x | ~700 |
| TeichAI/claude-4.5-opus-high-reasoning-250x | ~250 |
| Roman1111111/gemini-3.1-pro-hard-high-reasoning | full |
| ianncity/KIMI-K2.5-1000000x (General-Distillation) | 15 000 |
| Roman1111111/claude-opus-4.6-10000x | ~10 000 |
| Jackrong/GLM5.1-Reasoning-1M-Cleaned (PHD-Science) | 3 000 |
| Jackrong/GLM5.1-Reasoning-1M-Cleaned (Math) | 2 000 |

### Training config

| Parameter | Value |
|---|---|
| Max sequence length | 3 072 |
| LoRA rank / alpha | 32 / 32 |
| Epochs | 2 |
| Learning rate | 2e-4 (cosine) |
| Effective batch size | 8 (batch 1 × grad_accum 8) |
| Optimizer | adamw_8bit |
| BF16 | yes |

---

## Output format

When triggered correctly, the model wraps its reasoning in a thinking channel and
then gives the final answer:

```
<|channel>thought
1. First I analyze...
2. Then I consider...
3. Therefore...
<channel|>
Final answer here.
```

---

## Quick start

> **Critical:** include `<|think|>` in the system prompt — without it the thinking
> channel will not activate.

### With PEFT + transformers

```python
from peft import PeftModel
from transformers import AutoModelForCausalLM, AutoTokenizer

base = "google/gemma-4-E4B-IT"
adapter = "Zhantas/DeepGemma-E4B-Reasoning"

tokenizer = AutoTokenizer.from_pretrained(base)
model = AutoModelForCausalLM.from_pretrained(base, device_map="auto")
model = PeftModel.from_pretrained(model, adapter)

messages = [
    {"role": "system",    "content": "<|think|>"},
    {"role": "user",      "content": "How many r's are in strawberry? Think step by step."},
]

inputs = tokenizer.apply_chat_template(
    messages,
    tokenize=True,
    add_generation_prompt=True,
    return_tensors="pt",
).to("cuda")

out = model.generate(
    inputs,
    max_new_tokens=512,
    temperature=0.7,
    top_p=0.95,
    do_sample=True,
)
print(tokenizer.decode(out[0], skip_special_tokens=False))
```

### With Unsloth (faster inference)

```python
from unsloth import FastLanguageModel

model, tokenizer = FastLanguageModel.from_pretrained(
    "Zhantas/DeepGemma-E4B-Reasoning",
    load_in_4bit=True,
)
FastLanguageModel.for_inference(model)

tok = tokenizer.tokenizer if hasattr(tokenizer, "tokenizer") else tokenizer

prompt = tok.apply_chat_template(
    [
        {"role": "system", "content": "<|think|>"},
        {"role": "user",   "content": "Prove that sqrt(2) is irrational."},
    ],
    tokenize=False,
    add_generation_prompt=True,
)

inputs = tok(prompt, return_tensors="pt").to("cuda")
out = model.generate(**inputs, max_new_tokens=1024, temperature=0.7, top_p=0.95, do_sample=True)
print(tok.decode(out[0], skip_special_tokens=False))
```

---

## Limitations

- The adapter was trained on English and Russian data; performance on other languages is untested.
- Very long reasoning chains (> 3 072 tokens total) may be truncated.
- As a LoRA adapter the base model weights are unchanged; all base model limitations apply.

---

## License

This adapter inherits the [Gemma license](https://ai.google.dev/gemma/terms). Use is subject
to Google's Gemma terms of service.

---

Trained with [Unsloth](https://github.com/unslothai/unsloth).