Analytical Results on the BFS vs. DFS Algorithm Selection Problem. Part I: Tree Search
نویسندگان
چکیده
The algorithm selection problem asks to select the best algorithm for a given problem. In the companion paper Everitt and Hutter (2015b), expected runtime was approximated as a function of search depth and probabilistic goal distribution for tree search versions of breadth-first search (BFS) and depth-first search (DFS). Here we provide an analogous analysis of BFS and DFS graph search, deriving expected runtime as a function of graph structure and goal distribution. The applicability of the method is demonstrated through analysis of two different grammar problems. The approximations come surprisingly close to empirical reality.
منابع مشابه
Analytical Results on the BFS vs . DFS Algorithm Selection Problem
Breadth-first search (BFS) and depth-first search (DFS) are the two most fundamental search algorithms. We derive approximations of their expected runtimes in complete trees, as a function of tree depth and probabilistic goal distribution. We also demonstrate that the analytical approximations are close to the empirical averages for most parameter settings, and that the results can be used to p...
متن کاملA Topological Approach to Meta-heuristics: Analytical Results on the BFS vs. DFS Algorithm Selection Problem
Search is a central problem in artificial intelligence, and BFS and DFS the two most fundamental ways to search. In this report we derive results for average BFS and DFS runtime: For tree search, we employ a probabilistic model of goal distribution; for graph search, the analysis depends on an additional statistic of path redundancy and average branching factor. As an application, we use the re...
متن کاملI/O-Efficient Planar Separators and Applications
We present a new algorithm to compute a subset S of vertices of a planar graph G whose removal partitions G into O(N=h) subgraphs of size O(h) and with boundary size O(ph) each. The size of S is O(N=ph). Computing S takes O(sort(N)) I/Os and linear space, provided that M 56h log2 B. Together with recent reducibility results, this leads to O(sort(N)) I/O algorithms for breadth-first search (BFS)...
متن کاملTheory and Techniques for Synthesizing a Family of Graph Algorithms
Although Breadth-First Search (BFS) has several advantages over Depth-First Search (DFS) its prohibitive space requirements have meant that algorithm designers often pass it over in favor of DFS. To address this shortcoming, we introduce a theory of Efficient BFS (EBFS) along with a simple recursive program schema for carrying out the search. The theory is based on dominance relations, a long s...
متن کاملAnytime Hybrid Best-First Search with Tree Decomposition for Weighted CSP
We propose Hybrid Best First Search (HBFS), a search strategy for optimization problems that combines Best First Search (BFS) and Depth First Search (DFS). Like BFS, HBFS provides an anytime global lower bound on the optimum, while also providing anytime upper bounds, like DFS. Hence, it provides feedback on the progress of search and solution quality in the form of an optimality gap. In additi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2015