Powered by OpenAIRE graph
Found an issue? Give us feedback
image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ ZENODOarrow_drop_down
image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
ZENODO
Other literature type . 2025
License: CC BY
Data sources: ZENODO
ZENODO
Data Paper . 2025
License: CC BY
Data sources: Datacite
addClaim

Small Singular Values Matter: A Random Matrix Analysis of Transformer Models

Small Singular Values Matter: A Random Matrix Analysis of Transformer Models

Abstract

This work analyzes the spectra of weight matrices in pretrained transformer models to understand the role of outliers. When comparing Random Matrix Theory (RMT) predictions to properties of trained weights, we associate agreement with random noise and deviations with learned structure. Surprisingly, we find that the RMTpredictions for spectral properties are not only violated for the large singular values, but also for the small ones. A comparison of the corresponding singular vectors to eigenvectors of the activation covariance matrices shows a substantial overlap in regions that deviate from RMT expectations, indicating that important directions of the data could be encoded in small singular values. We verify this result by measuring the perplexity increase when removing these singular values from the matrix and find that they indeed encode important information, as their removal leads to higher perplexity increases than removing singular values from the bulk of the spectrum. When fine-tuning, the smallest singular values can even be the third most important decile of the singular value spectrum. Finally, we introduce a linear random matrix model to explain how singular vectors corresponding to small singular values can carry more information than those corresponding to larger ones. Our results highlight the relevance of small singular values and offer both theoretical and empirical insights, informing the design of SVD-based pruning methods in large language models.

  • BIP!
    Impact byBIP!
    selected citations
    These citations are derived from selected sources.
    This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    0
    popularity
    This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
    Average
    influence
    This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    Average
    impulse
    This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
    Average
Powered by OpenAIRE graph
Found an issue? Give us feedback
selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
Average