Learning linear acyclic causal model containing Gaussian disturbances using ancestral relationships
摘要
The problem of learning causal directed acyclic graphs (DAGs) has attracted considerable attention. The Peter-Clark (PC) algorithm (Spirtes et al. Causation, Prediction, and Search, MIT Press, Cambridge, 2001), which relies solely on faithfulness and Markov assumptions, can identify a causal DAG up to its Markov equivalence class (MEC). In contrast, the linear non-Gaussian acyclic model (LiNGAM) (Shimizu et al. in J Mach Learn Res 7:2003–2030, 2006) achieves the full identifiability of edge orientations in a causal DAG by additionally assuming linearity and continuous non-Gaussian disturbances for the causal model. By combining the strength of the PC algorithm, namely, not requiring any specification of exogenous disturbances, with that of LiNGAM in orienting causal edges, the PC-LiNGAM (Hoyer et al. in: Proceedings of the twenty-fourth conference on uncertainty in artificial intelligence, UAI2008, 2008) can identify a causal DAG up to its distribution-equivalence pattern (DEP), even in the presence of Gaussian disturbances. However, in the worst case, the PC-LiNGAM suffers from O(p!) time complexity, where p is the number of variables, making it impractical for high-dimensional settings. In this paper, we propose an algorithm for learning the DEP of a linear causal model with