ComfyUI-ModelMergeCosmosPredict2-2B-Slerp

A specialized ComfyUI custom node for merging Cosmos Predict 2 2B models using Slerp (Spherical Linear Interpolation) and Linear Interpolation, also compatible with the currently trending Anima model developed by circlestone-labs.

Unlike standard linear merging, Slerp preserves the magnitude of the weight vectors, resulting in sharper and more stable outputs when merging models with significantly different characteristics or styles.

Features

• Slerp & Linear Support: Seamlessly switch between Slerp and standard Linear (weighted average) interpolation via a simple dropdown menu.
• Layer-wise Ratio Control: Adjust the merge ratio for each specific layer (Embeddings, 28 Transformer Blocks, Final Layer) individually using dedicated sliders.
• Safe Fallback Mechanism: Automatically falls back to Linear interpolation if Slerp encounters numerical instability (e.g., zero-norm tensors or shape mismatches), ensuring a crash-free workflow.
• Optimized Memory Management: Properly handles VRAM cleanup and model patching following ComfyUI's best practices.
• Drop-in Replacement: Fully compatible with the original ModelMergeCosmosPredict2_2B node structure.

📦 Installation

Option 1: ComfyUI Manager (Recommended)

1. Open ComfyUI Manager.
2. Click on "Install via Git URL".
3. Paste the following URL and click Install:

   https://github.com/rikunarita/ComfyUI-ModelMergeCosmosPredict2-2B-Slerp.git
   

4. Restart ComfyUI.

Option 2: Manual Installation

1. Navigate to your ComfyUI/custom_nodes/ directory.
2. Clone this repository:

   git clone https://github.com/rikunarita/ComfyUI-ModelMergeCosmosPredict2-2B-Slerp.git
   

3. Restart ComfyUI.

🚀 Usage

1. Load two Cosmos Predict 2B checkpoints using the standard Load Checkpoint nodes.
2. Add the Model Merge Cosmos Predict 2 2B (Slerp) node to your graph.
3. Connect the two models to model1 and model2.
4. Set the merge_mode to either slerp or linear.
5. Adjust the individual sliders for each block to control the blending ratio (0.0 to 1.0).
6. Connect the output to a KSampler or other downstream nodes.

Parameters Explained

Parameter	Type	Default	Description
merge_mode	Combo	slerp	Selects the interpolation algorithm. slerp for sharp blending, linear for standard weighted average.
pos_embedder.	Float	1.0	Merge ratio for the positional embedding layer.
x_embedder.	Float	1.0	Merge ratio for the input (pixel) embedding layer.
t_embedder.	Float	1.0	Merge ratio for the time embedding layer.
t_embedding_norm.	Float	1.0	Merge ratio for the time embedding normalization layer.
blocks.0. ~ blocks.27.	Float	1.0	Merge ratios for the 28 individual Transformer blocks.
final_layer.	Float	1.0	Merge ratio for the final output projection layer.

📝 Node Details

• Node Name: ModelMergeCosmosPredict2_2B_Slerp
• Display Name: Model Merge Cosmos Predict 2 2B (Slerp)
• Category: model/merging/model specific
• Inputs:
  • model1 (MODEL)
  • model2 (MODEL)
• Outputs:
  • MODEL (Merged Model)

🛠 Technical Notes

• Numerical Stability: The Slerp implementation includes strict numerical safeguards, including zero-norm prevention, dot-product clamping, and automatic fallback to Linear interpolation when the angle between vectors is too small (DOT_THRESHOLD=0.9995).
• State Dict Handling: Uses strict=False when loading the merged state dictionary to gracefully handle any minor structural discrepancies between the two source models.

📄 License & Credits

This custom node is built upon the architecture of the official ComfyUI model merging nodes (comfy_extras.nodes_model_merging).

• ComfyUI: ComfyUI Official Repository
• Slerp Math: Standard Spherical Linear Interpolation adapted for high-dimensional PyTorch tensors.

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Made with ❤️ for the ComfyUI Community.