Differentiable Interacting Multiple Model Particle Filtering
John-Joseph Brady, Yuhui Luo, Wenwu Wang, Víctor Elvira, Yunpeng Li
TL;DR
The paper tackles learning in regime-switching state-space models where switching dynamics are unknown. It develops the Differentiable Interacting Multiple Model Particle Filter (DIMMPF), a differentiable extension of the IMMPF that jointly learns per-regime models and the switching mechanism via gradient descent. The authors prove consistency of their estimators and gradient signals, and show through simulations that DIMMPF achieves state-of-the-art filtering accuracy across Markov, Polya-urn, and Erlang-like switching patterns. While computationally intensive during training, the DIMMPF yields competitive inference speed and offers a principled framework for learning high-dimensional switching dynamics in sequential data.
Abstract
We propose a sequential Monte Carlo algorithm for parameter learning when the studied model exhibits random discontinuous jumps in behaviour. To facilitate the learning of high dimensional parameter sets, such as those associated to neural networks, we adopt the emerging framework of differentiable particle filtering, wherein parameters are trained by gradient descent. We design a new differentiable interacting multiple model particle filter to be capable of learning the individual behavioural regimes and the model which controls the jumping simultaneously. In contrast to previous approaches, our algorithm allows control of the computational effort assigned per regime whilst using the probability of being in a given regime to guide sampling. Furthermore, we develop a new gradient estimator that has a lower variance than established approaches and remains fast to compute, for which we prove consistency. We establish new theoretical results of the presented algorithms and demonstrate superior numerical performance compared to the previous state-of-the-art algorithms.
