118 research outputs found
OCDaf: Ordered Causal Discovery with Autoregressive Flows
We propose OCDaf, a novel order-based method for learning causal graphs from
observational data. We establish the identifiability of causal graphs within
multivariate heteroscedastic noise models, a generalization of additive noise
models that allow for non-constant noise variances. Drawing upon the structural
similarities between these models and affine autoregressive normalizing flows,
we introduce a continuous search algorithm to find causal structures. Our
experiments demonstrate state-of-the-art performance across the Sachs and
SynTReN benchmarks in Structural Hamming Distance (SHD) and Structural
Intervention Distance (SID). Furthermore, we validate our identifiability
theory across various parametric and nonparametric synthetic datasets and
showcase superior performance compared to existing baselines
Learning Causal Graphs via Monotone Triangular Transport Maps
We study the problem of causal structure learning from data using optimal
transport (OT). Specifically, we first provide a constraint-based method which
builds upon lower-triangular monotone parametric transport maps to design
conditional independence tests which are agnostic to the noise distribution. We
provide an algorithm for causal discovery up to Markov Equivalence with no
assumptions on the structural equations/noise distributions, which allows for
settings with latent variables. Our approach also extends to score-based causal
discovery by providing a novel means for defining scores. This allows us to
uniquely recover the causal graph under additional identifiability and
structural assumptions, such as additive noise or post-nonlinear models. We
provide experimental results to compare the proposed approach with the state of
the art on both synthetic and real-world datasets.Comment: 20 pages, 6 figures, under revie
GFlowCausal: Generative Flow Networks for Causal Discovery
Causal discovery aims to uncover causal structure among a set of variables.
Score-based approaches mainly focus on searching for the best Directed Acyclic
Graph (DAG) based on a predefined score function. However, most of them are not
applicable on a large scale due to the limited searchability. Inspired by the
active learning in generative flow networks, we propose a novel approach to
learning a DAG from observational data called GFlowCausal. It converts the
graph search problem to a generation problem, in which direct edges are added
gradually. GFlowCausal aims to learn the best policy to generate high-reward
DAGs by sequential actions with probabilities proportional to predefined
rewards. We propose a plug-and-play module based on transitive closure to
ensure efficient sampling. Theoretical analysis shows that this module could
guarantee acyclicity properties effectively and the consistency between final
states and fully-connected graphs. We conduct extensive experiments on both
synthetic and real datasets, and results show the proposed approach to be
superior and also performs well in a large-scale setting
Learning tractable multidimensional Bayesian network classifiers
Multidimensional classification has become one of the most relevant topics in view of the many
domains that require a vector of class values to be assigned to a vector of given features. The
popularity of multidimensional Bayesian network classifiers has increased in the last few years
due to their expressive power and the existence of methods for learning different families of these
models. The problem with this approach is that the computational cost of using the learned models
is usually high, especially if there are a lot of class variables. Class-bridge decomposability means
that the multidimensional classification problem can be divided into multiple subproblems for these
models. In this paper, we prove that class-bridge decomposability can also be used to guarantee
the tractability of the models. We also propose a strategy for efficiently bounding their inference
complexity, providing a simple learning method with an order-based search that obtains tractable
multidimensional Bayesian network classifiers. Experimental results show that our approach is
competitive with other methods in the state of the art and ensures the tractability of the learned
models
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