Title
Intrinsic dimension of data representations in deep neural networks.
Abstract
Deep neural networks progressively transform their inputs across multiple processing layers. What are the geometrical properties of the representations learned by these networks? Here we study the intrinsic dimensionality (ID) of data-representations, i.e. the minimal number of parameters needed to describe a representation. We find that, in a trained network, the ID is orders of magnitude smaller than the number of units in each layer. Across layers, the ID first increases and then progressively decreases in the final layers. Remarkably, the ID of the last hidden layer predicts classification accuracy on the test set. These results can neither be found by linear dimensionality estimates (e.g., with principal component analysis), nor in representations that had been artificially linearized. They are neither found in untrained networks, nor in networks that are trained on randomized labels. This suggests that neural networks that can generalize are those that transform the data into low-dimensional, but not necessarily flat manifolds.
Year
Venue
Keywords
2019
ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 32 (NIPS 2019)
neural networks
Field
DocType
Volume
Orders of magnitude (numbers),Pattern recognition,Curse of dimensionality,Intrinsic dimension,Artificial intelligence,Artificial neural network,Machine learning,Manifold,Mathematics,Deep neural networks,Principal component analysis,Test set
Journal
32
ISSN
Citations 
PageRank 
1049-5258
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Alessio Ansuini101.69
Alessandro Laio24110.47
Jakob H Macke315814.15
Davide Zoccolan471.64