Skip to yearly menu bar Skip to main content


Oral

Oral Session 5: Probabilistic Inference and Optimzation

Abstract:
Chat is not available.

We propose a novel, tractable latent state inference scheme for Markov jump processes, for which exact inference is often intractable. Our approach is based on an entropic matching framework that can be embedded into the well-known expectation propagation algorithm.We demonstrate the effectiveness of our method by providing closed-form results for a simple family of approximate distributions and apply it to the general class of chemical reaction networks, which are a crucial tool for modeling in systems biology.Moreover, we derive closed-form expressions for point estimation of the underlying parameters using an approximate expectation maximization procedure. We evaluate our method across various chemical reaction networks and compare it to multiple baseline approaches, demonstrating superior performance in approximating the mean of the posterior process. Finally, we discuss the limitations of our method and potential avenues for future improvement, highlighting its promising direction for addressing complex continuous-time Bayesian inference problems.


Information Transfer Across Clinical Tasks via Adaptive Parameter Optimisation

Anshul Thakur · Elena Gal · Soheila Molaei · Xiao Gu · Patrick Schwab · Danielle Belgrave · Kim Branson · David Clifton

This paper presents Adaptive Parameter Optimisation (APO), a novel framework for optimising shared models across multiple clinical tasks, addressing the challenges of balancing strict parameter sharing—often leading to task conflicts—and soft parameter sharing, which may limit effective cross-task information exchange. The proposed APO framework leverages insights from the lazy behaviour observed in over-parameterised neural networks, where only a small subset of parameters undergo any substantial updates during training. APO dynamically identifies and updates task-specific parameters while treating parameters associated with other tasks as protected, limiting their modification to prevent interference. The remaining unassigned parameters remain unchanged, embodying the lazy training phenomenon. This dynamic management of task-specific, protected, and unclaimed parameters across tasks enables effective information sharing, preserves task-specific adaptability, and mitigates gradient conflicts without enforcing a uniform representation. Experimental results across diverse healthcare datasets demonstrate that APO surpasses traditional information-sharing approaches, such as multi-task learning and model-agnostic meta-learning, in improving task performance.


posteriordb: Testing, Benchmarking and Developing Bayesian Inference Algorithms

Måns Magnusson · Jakob Torgander · Paul Bürkner · Lu Zhang · Bob Carpenter · Aki Vehtari

The general applicability and robustness of posterior inference algorithms is critical to widely used probabilistic programming languages such as Stan, PyMC, Pyro, and Turing.jl. When designing a new inference algorithm, whether it involves Monte Carlo sampling or variational approximation, the fundamental problem is evaluating its accuracy and efficiency across a range of representative target posteriors. To solve this problem, we propose posteriordb, a database of models and data sets defining target densities along with reference Monte Carlo draws. We further provide a guide to the best practices in using posteriordb for algorithm evaluation and comparison. To provide a wide range of realistic posteriors, posteriordb currently comprises 120 representative models with data, and has been instrumental in developing several inference algorithms.


Restructuring Tractable Probabilistic Circuits

Honghua Zhang · Benjie Wang · Marcelo Arenas · Guy Van den Broeck

Probabilistic circuits (PCs) are a unifying representation for probabilistic models that support tractable inference. Numerous applications of PCs like controllable text generation depend on the ability to efficiently multiply two circuits. Existing multiplication algorithms require that the circuits respect the same structure, i.e. variable scopes decomposes according to the same vtree. In this work, we propose and study the task of restructuring structured(-decomposable) PCs, that is, transforming a structured PC such that it conforms to a target vtree. We propose a generic approach for this problem and show that it leads to novel polynomial-time algorithms for multiplying circuits respecting different vtrees, as well as a practical depth-reduction algorithm that preserves structured decomposibility. Our work opens up new avenues for tractable PC inference, suggesting the possibility of training with less restrictive PC structures while enabling efficient inference by changing their structures at inference time.

Uncertainty quantification in deep learning is crucial for safe and reliable decision-making in downstream tasks. Existing methods quantify uncertainty at the last layer or other approximations of the network which may miss some sources of uncertainty in the model. To address this gap, we propose an uncertainty quantification method for large networks based on variation due to regularization. Essentially, predictions that are more (less) sensitive to the regularization of network parameters are less (more, respectively) certain. This principle can be implemented by deterministically tweaking the training loss during the fine-tuning phase and reflects confidence in the output as a function of all layers of the network. We show that regularization variation (RegVar) provides rigorous uncertainty estimates that, in the infinitesimal limit, exactly recover the Laplace approximation in Bayesian deep learning. We demonstrate its success in several deep learning architectures, showing it can scale tractably with the network size while maintaining or improving uncertainty quantification quality. Our experiments across multiple datasets show that RegVar not only identifies uncertain predictions effectively but also provides insights into the stability of learned representations.