Papers › CaloFlow: Fast and Accurate Generation of Calorimeter Showers with Normalizing Flows

CaloFlow: Fast and Accurate Generation of Calorimeter Showers with Normalizing Flows

9 Jun 2021arXiv:2106.05285archive 2025-07-28

Claudius Krause, David Shih

We introduce CaloFlow, a fast detector simulation framework based on normalizing flows. For the first time, we demonstrate that normalizing flows can reproduce many-channel calorimeter showers with extremely high fidelity, providing a fresh alternative to computationally expensive GEANT4 simulations, as well as other state-of-the-art fast simulation frameworks based on GANs and VAEs. Besides the usual histograms of physical features and images of calorimeter showers, we introduce a new metric for judging the quality of generative modeling: the performance of a classifier trained to differentiate real from generated images. We show that GAN-generated images can be identified by the classifier with nearly 100% accuracy, while images generated from CaloFlow are better able to fool the classifier. More broadly, normalizing flows offer several advantages compared to other state-of-the-art approaches (GANs and VAEs), including: tractable likelihoods; stable and convergent training; and principled model selection. Normalizing flows also provide a bijective mapping between data and the latent space, which could have other applications beyond simulation, for example, to detector unfolding.

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gitlab.com/claudius-krause/caloflow officialmentioned in papermentioned on GitHubpytorch report
gitlab.com/imahn/l2lflows mentioned on GitHubpytorch report

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Normalizing Flows

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