Fixed-kinetic Neural Hamiltonian Flows for enhanced interpretability and
reduced complexity
- URL: http://arxiv.org/abs/2302.01955v1
- Date: Fri, 3 Feb 2023 19:05:57 GMT
- Title: Fixed-kinetic Neural Hamiltonian Flows for enhanced interpretability and
reduced complexity
- Authors: Vincent Souveton, Arnaud Guillin, Jens Jasche, Guilhem Lavaux, Manon
Michel
- Abstract summary: We introduce a fixed kinetic energy version of the Neural Hamiltonian Flows (NHF) model.
Inspired by physics, our approach improves interpretability and requires less parameters than previously proposed architectures.
We also adapt NHF to the context of Bayesian inference and illustrate our method on sampling the posterior distribution of two cosmological parameters.
- Score: 0.0
- License: http://creativecommons.org/licenses/by-sa/4.0/
- Abstract: Normalizing Flows (NF) are Generative models which are particularly robust
and allow for exact sampling of the learned distribution. They however require
the design of an invertible mapping, whose Jacobian determinant has to be
computable. Recently introduced, Neural Hamiltonian Flows (NHF) are based on
Hamiltonian dynamics-based Flows, which are continuous, volume-preserving and
invertible and thus make for natural candidates for robust NF architectures. In
particular, their similarity to classical Mechanics could lead to easier
interpretability of the learned mapping. However, despite being
Physics-inspired architectures, the originally introduced NHF architecture
still poses a challenge to interpretability. For this reason, in this work, we
introduce a fixed kinetic energy version of the NHF model. Inspired by physics,
our approach improves interpretability and requires less parameters than
previously proposed architectures. We then study the robustness of the NHF
architectures to the choice of hyperparameters. We analyze the impact of the
number of leapfrog steps, the integration time and the number of neurons per
hidden layer, as well as the choice of prior distribution, on sampling a
multimodal 2D mixture. The NHF architecture is robust to these choices,
especially the fixed-kinetic energy model. Finally, we adapt NHF to the context
of Bayesian inference and illustrate our method on sampling the posterior
distribution of two cosmological parameters knowing type Ia supernovae
observations.
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