Exact Search
Algorithm Introduction
Search for the optimal graph using Dynamic Programming (DP 1) or A* search 2.
Usage
from causallearn.search.ScoreBased.ExactSearch import bic_exact_search dag_est, search_stats = bic_exact_search(X, super_graph, search_method, use_path_extension, use_k_cycle_heuristic, k, verbose, include_graph, max_parents)
Parameters
X: numpy.ndarray, shape=(n, d). The data to fit the structure too, where each row is a sample and each column corresponds to the associated variable.
super_graph: numpy.ndarray, shape=(d, d). Super-structure to restrict search space (binary matrix). If None, no super-structure is used. Default is None.
search_method: str. Method of exact search ([‘astar’, ‘dp’]). Default is astar.
use_path_extension: bool. Whether to use optimal path extension for order graph. Note that this trick will not affect the correctness of search procedure. Default is True.
use_k_cycle_heuristic: bool. Whether to use k-cycle conflict heuristic for astar. Default is False.
k: int. Parameter used by k-cycle conflict heuristic for astar. Default is 3.
verbose: bool. Whether to log messages related to search procedure.
max_parents: int. The maximum number of parents a node can have. If used, this means using the k-learn procedure. Can drastically speed up algorithms. If None, no max on parents. Default is None.
Returns
dag_est: numpy.ndarray, shape=(d, d). Estimated DAG.
search_stats: dict. Some statistics related to the seach procedure.
- 1
Silander, T., & Myllymäki, P. (2006, July). A simple approach for finding the globally optimal Bayesian network structure. In Proceedings of the Twenty-Second Conference on Uncertainty in Artificial Intelligence (pp. 445-452).
- 2
Yuan, C., & Malone, B. (2013). Learning optimal Bayesian networks: A shortest path perspective. Journal of Artificial Intelligence Research, 48, 23-65.