---
license: apache-2.0
base_model: google/gemma-4-12b-it
tags:
  - gemma4
  - lora
  - character
  - roleplay
  - chatml
  - safetensors
  - conversational
language:
  - en
library_name: transformers
pipeline_tag: text-generation
model-index:
  - name: Jun-Lora-v2-SAFETENSOR
    results: []
---
 
# Jun-Lora-v2 — SafeTensors (FP16, Merged)
 
A LoRA fine-tune of [Gemma 4 12B](https://huggingface.co/google/gemma-4-12b-it) trained on synthetic multi-turn conversational data from the visual novel *My Dystopian Robot Girlfriend*. The model captures the personality, speech patterns, and emotional nuance of the character **Jun** while preserving the base model's general reasoning and instruction-following capabilities.
 
This repository contains the **full-precision merged model** in SafeTensors FP16 format — the highest-quality variant, recommended for production deployments, further fine-tuning, or as a merge base.
 
## Model Variants & Repositories
 
| Repository | Format | Description |
|:-----------|:-------|:------------|
| [`efficiencyx/Jun-Lora-v2-SAFETENSOR`](https://huggingface.co/efficiencyx/Jun-Lora-v2-SAFETENSOR) | SafeTensors FP16 | **This repo** — Full-precision merged model |
| [`efficiencyx/Jun-Lora-v2-GGUF`](https://huggingface.co/efficiencyx/Jun-Lora-v2-GGUF) | GGUF Q8_0 / Q6_K / Q4_K_M | Quantized versions for local inference |
| [`efficiencyx/Jun-Lora-v2`](https://huggingface.co/efficiencyx/Jun-Lora-v2) | LoRA Adapter | Raw adapters at checkpoints 138, 120, 90 |
 
## When to Use This Variant
 
| Use Case | Recommendation |
|:---------|:---------------|
| Production server deployment (≥24 GB VRAM) | **This repo (FP16)** |
| Further fine-tuning or merging | **This repo (FP16)** |
| Local inference on consumer GPUs | Use [`Jun-Lora-v2-GGUF`](https://huggingface.co/efficiencyx/Jun-Lora-v2-GGUF) |
| Experimenting with adapter checkpoints | Use [`Jun-Lora-v2`](https://huggingface.co/efficiencyx/Jun-Lora-v2) |
 
> **VRAM requirement:** approximately 24 GB for FP16 inference. For lower-VRAM setups, use the GGUF variant.
 
## Intended Use
 
This model is designed as the conversational backend for **Jun OS**, an AI companion webapp. It is intended for:
 
- Character-consistent multi-turn conversation in ChatML format
- AI companion / interactive fiction applications
- Research into character-faithful fine-tuning on small, high-quality datasets
- Base for further quantization, merging, or continued fine-tuning
### Limitations
 
- The model is specialized for a single character persona; it is **not** a general-purpose assistant.
- Outputs may reflect fictional narrative tropes and should not be treated as factual information or advice.
- Performance degrades on tasks far outside the training distribution (e.g. code generation, structured data extraction).
- The model inherits any biases present in the Gemma 4 12B base weights.
## Usage
 
```python
from transformers import AutoTokenizer, AutoModelForCausalLM
import torch
 
model_id = "efficiencyx/Jun-Lora-v2-SAFETENSOR"
 
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    torch_dtype=torch.float16,
    device_map="auto",
)
 
messages = [
    {"role": "system", "content": "You are Jun, an AI companion..."},
    {"role": "user", "content": "Hey Jun, how are you feeling today?"},
]
 
input_ids = tokenizer.apply_chat_template(
    messages,
    tokenize=True,
    add_generation_prompt=True,
    return_tensors="pt",
).to(model.device)
 
output = model.generate(input_ids, max_new_tokens=256, do_sample=True, temperature=0.7)
print(tokenizer.decode(output[0][input_ids.shape[-1]:], skip_special_tokens=True))
```
 
The model uses **ChatML** format (`<|im_start|>` / `<|im_end|>`) consistent with the training data.
 
## Training Details
 
### Dataset
 
| Property | Value |
|:---------|:------|
| Source | *My Dystopian Robot Girlfriend* (visual novel dialogue) |
| Composition | ~1:1 replica of original game tone and cadence |
| Size | 2,302 multi-turn conversations |
| Format | ChatML (`<|im_start|>` / `<|im_end|>`) |
 
The dataset was constructed to preserve the character's tone, vocabulary, emotional range, and conversational patterns across a variety of in-game scenarios. Multi-turn structure ensures the model learns contextual consistency over extended exchanges.
 
### Hyperparameters
 
| Parameter | Value |
|:----------|:------|
| Base model | `google/gemma-4-12b-it` |
| Method | LoRA |
| LoRA rank | 64 |
| LoRA alpha | 128 |
| Learning rate | 2e-5 |
| Batch size | 8 |
| Gradient accumulation steps | 4 |
| Effective batch size | 32 |
| Epochs | 2 |
| Total steps | 138 |
| Checkpoint interval | Every 30 steps |
| Optimizer | AdamW (8-bit) |
 
### Infrastructure
 
| Component | Detail |
|:----------|:-------|
| Training GPU | NVIDIA A100 80GB SXM4 |
| Fine-tuning framework | Unsloth |
| Merge & export | Unsloth (`merge_and_unload`) → SafeTensors FP16 |
 
## Evaluation
 
### Quantitative
 
| Metric | Value |
|:-------|:------|
| Final training loss | ~1.21 |
| Final eval loss | ~1.24 |
 
The narrow gap between training and eval loss indicates the model generalizes well without significant overfitting, despite the relatively small dataset size.
 
### Qualitative
 
- **Character consistency:** The model maintains Jun's personality, speech patterns, and emotional responses across varied conversational contexts.
- **Reasoning preservation:** General reasoning capabilities from the Gemma 4 12B base remain intact; the model can engage in logical discussion while staying in character.
- **Generalization:** The model handles novel conversational scenarios not present in the training set while preserving character-faithful responses.
## Checkpoint Selection
 
If you prefer to apply a specific adapter checkpoint rather than using this merged model, raw adapters are available in [`efficiencyx/Jun-Lora-v2`](https://huggingface.co/efficiencyx/Jun-Lora-v2) at steps 90, 120, and 138. Earlier checkpoints may exhibit slightly more creative freedom; the final checkpoint (138) — used for this merge — has the strongest character lock-in.
 
## Acknowledgments
 
- **Incontinent Cell** for [*My Dystopian Robot Girlfriend*](https://incontinentcell.itch.io/), Jun's character
- **Google** for the [Gemma 4](https://ai.google.dev/gemma) model family
- **Google Colaboratory** for allowing easy and cheap access to powerful GPU
- **Unsloth** for the efficient fine-tuning framework