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Stationary Representations: Optimally Approximating Compatibility and Implications for Improved Model Replacements

4 May 2024CVPR 2024 1arXiv:2405.02581archive 2025-07-28

Niccolò Biondi, Federico Pernici, Simone Ricci, Alberto del Bimbo

Learning compatible representations enables the interchangeable use of semantic features as models are updated over time. This is particularly relevant in search and retrieval systems where it is crucial to avoid reprocessing of the gallery images with the updated model. While recent research has shown promising empirical evidence, there is still a lack of comprehensive theoretical understanding about learning compatible representations. In this paper, we demonstrate that the stationary representations learned by the d-Simplex fixed classifier optimally approximate compatibility representation according to the two inequality constraints of its formal definition. This not only establishes a solid foundation for future works in this line of research but also presents implications that can be exploited in practical learning scenarios. An exemplary application is the now-standard practice of downloading and fine-tuning new pre-trained models. Specifically, we show the strengths and critical issues of stationary representations in the case in which a model undergoing sequential fine-tuning is asynchronously replaced by downloading a better-performing model pre-trained elsewhere. Such a representation enables seamless delivery of retrieval service (i.e., no reprocessing of gallery images) and offers improved performance without operational disruptions during model replacement. Code available at: https://github.com/miccunifi/iamcl2r.

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average_compatibility miccunifi/iamcl2r/src/iamcl2r/compatibility_metrics.py official repository ran MIT (permissive) · b5f7093a7dc6780e · report
calculate_rank miccunifi/iamcl2r/src/iamcl2r/performance_metrics.py official repository ran MIT (permissive) · 67f77a8b85fc7644 · report
conv1x1 miccunifi/iamcl2r/src/iamcl2r/models/resnet.py official repository ran · our draft was wrong MIT (permissive) · d9def42110729a85 · report
conv3x3 miccunifi/iamcl2r/src/iamcl2r/models/resnet.py official repository ran · our draft was wrong MIT (permissive) · fac5364e2f53c6db · report
create_position_matrix miccunifi/iamcl2r/src/iamcl2r/compatibility_metrics.py official repository ran MIT (permissive) · 287980cbd8cfff17 · report
get_model_state_dict miccunifi/iamcl2r/src/iamcl2r/utils.py official repository ran MIT (permissive) · 5dc433f77db60966 · report
image2template_feature miccunifi/iamcl2r/src/iamcl2r/performance_metrics.py official repository ran fingerprinted MIT (permissive) · 9382be9297dfa6af · report
is_global_master miccunifi/iamcl2r/src/iamcl2r/utils.py official repository ran · violated contract MIT (permissive) · 7c29b374198bddcd · report
l2_norm miccunifi/iamcl2r/src/iamcl2r/utils.py official repository ran · our draft was wrong fingerprinted MIT (permissive) · c54fea429589425d · report
replace_zero_with_nan miccunifi/iamcl2r/src/iamcl2r/compatibility_metrics.py official repository ran fingerprinted MIT (permissive) · 60a694a2dbe60865 · report
resnet18 miccunifi/iamcl2r/src/iamcl2r/models/resnet.py official repository ran MIT (permissive) · 8b515b70ccc43a1a · report
setup_logger miccunifi/iamcl2r/src/iamcl2r/logger.py official repository ran MIT (permissive) · d4128b2fc26b8dd3 · report
calculate_mAP_gldv2 miccunifi/iamcl2r/src/iamcl2r/performance_metrics.py official repository unverified MIT (permissive) · 6c2652873cb4e88b · report
load_cifar_identification miccunifi/iamcl2r/src/iamcl2r/dataset/cifar.py official repository unverified MIT (permissive) · 3898ab7c82c0bea7 · report

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