Harmony in Diversity: Merging Neural Networks with Canonical Correlation Analysis

Published: 02 Mar 2024, Last Modified: 07 May 2024ICLR 2024 Workshop Re-Align PosterEveryoneRevisionsBibTeXCC BY 4.0
Track: short paper (up to 5 pages)
Keywords: Model Fusion, Model Alignment, Linear Mode Connectivity, Canonical Correlation Analysis
Abstract: Ensembling multiple models enhances predictive performance by utilizing the varied learned features of the different models but incurs significant computational and storage costs. Model fusion, which combines parameters from multiple models into one, aims to mitigate these costs but faces practical challenges due to the complex, non-convex nature of neural network loss landscapes, where learned minima are often separated by high loss barriers. Recent works have explored using permutations to align network features, reducing the loss barrier in parameter space. However, permutations are restrictive since they assume a one-to-one mapping between the different models' neurons exists. We propose a new model merging algorithm, CCA Merge, which is based on Canonical Correlation Analysis and aims to maximize the correlations between linear combinations of the model features. We show that our method of aligning models leads to better performances than past methods when averaging models trained on the same, or differing data splits. We also extend this analysis into the harder many models setting where more than 2 models are merged, and we find that CCA Merge works significantly better in this setting than past methods.
Anonymization: This submission has been anonymized for double-blind review via the removal of identifying information such as names, affiliations, and identifying URLs.
Submission Number: 52