Model Merging: Combining Pre-trained Models

When to Use This Skill

Use Model Merging when you need to:

• Combine capabilities from multiple fine-tuned models without retraining
• Create specialized models by blending domain-specific expertise (math + coding + chat)
• Improve performance beyond single models (often +5-10% on benchmarks)
• Reduce training costs - no GPUs needed, merges run on CPU
• Experiment rapidly - create new model variants in minutes, not days
• Preserve multiple skills - merge without catastrophic forgetting

Success Stories: Marcoro14-7B-slerp (best on Open LLM Leaderboard 02/2024), many top HuggingFace models use merging

Tools: mergekit (Arcee AI), LazyMergekit, Model Soup

Installation

# Install mergekit
git clone https://github.com/arcee-ai/mergekit.git
cd mergekit
pip install -e .

# Or via pip
pip install mergekit

# Optional: Transformer library
pip install transformers torch