Jakub Pawlewicz

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Various efficient game problem solvers are based on PNSearch. Especially depth-first versions of PN-Search like DF-PN or PDS – contrary to other known techniques – are able to solve really hard problems. However, the performance of DF-PN and PDS decreases dramatically when the search space significantly exceeds available memory. A simple trick to overcome(More)
In recent years the Monte Carlo tree search revolution has spread from computer Go to many areas, including computer Hex. MCTS Hex players now outperform traditional knowledge-based alpha-beta search players, and the reigning Computer Olympiad Hex gold medallist is the MCTS player MoHex. In this paper we show how to strengthen MoHex, and observe that — as(More)
We present the first sublinear-time algorithms for computing order statistics in the Farey sequence and for the related problem of ranking. Our algorithms achieve a running times of nearly O(n 2/3), which is a significant improvement over the previous algorithms taking time O(n). We also initiate the study of a more general problem: counting primitive(More)
Yahtzee is the most popular commercial dice game in the world. It can be played either by one or many players. In case of the single player version, optimal computer strategies both for maximizing the expected average score and for maximizing the probability of beating a particular score are already known. However, when it comes to the multi-player version,(More)
We present Scalable Parallel Depth-First Proof Number Search, a new shared-memory parallel version of depth-first proof number search. Based on the serial DFPN 1+ε method of Pawlewicz and Lew, SPDFPN searches effectively even as the transposition table becomes almost full, and so can solve large problems. To assign jobs to threads, SPDFPN uses proof and(More)
For some two-player games (e.g. Go), no accurate and inexpensive heuristic is known for evaluating leaves of a search tree. For other games (e.g. chess), a heuristic is known (sum of piece values). For other games (e.g. Hex), only a local heuristic — one that compares children reliably, but nonsiblings poorly — is known (cell voltage drop in the(More)
Recently we introduced Sibling Conspiracy Number Search — an algorithm based not on evaluation of leaf states of the search tree but, for each node, on relative evaluation scores of all children of that node — and implemented an SCNS Hex bot. Here we show the strength of SCNS features: most critical is to initialize leaves via a multi-step process. Also, we(More)