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Writing parallel applications for computational grids is a challenging task. To achieve good performance, algorithms designed for local area networks must be adapted to the differences in link speeds. An important class of algorithms are collective operations, such as broadcast and reduce. We have developed M<sc>AG</sc>PI<sc>E</sc>, a library of collective(More)
This paper introduces a new scheduling algorithm for parallel single-agent search, transposition table driven work scheduling, that places the transposition table at the heart of the parallel work scheduling. The scheme results in less synchronization overhead, less processor idle time, and less redundant search effort. Measurements on a 128-processor(More)
This article has three main contributions to our understanding of minimax search: First, a new formulation for Stockman’s SSS* algorithm, based on AlphaBeta, is presented. It solves all the perceived drawbacks of SSS*, finally transforming it into a practical algorithm. In effect, we show that SSS* = Alpha-Beta + transposition tables. The crucial step is(More)
This paper studies application performance on systems with strongly non-uniform remote memory access. In current generation NUMAs the speed difference between the slowest and fastest link in an interconnect—the “NUMA gap”—is typically less than an order of magnitude, and many conventional parallel programs achieve good performance. We study how different(More)
Java offers interesting opportunities for parallel computing. In particular, Java Remote Method Invocation provides an unusually flexible kind of Remote Procedure Call. Unlike RPC, RMI supports polymorphism, which requires the system to be able to download remote classes into a running application. Sun's RMI implementation achieves this kind of flexibility(More)
The state space of most adversary games is a directed graph. However, due to the success of simple recursive algorithms based on Alpha-Beta, theoreticians and practitioners have concentrated on the traversal of trees, giving the field the name “game-tree search.” This paper shows that the focus on trees has obscured some important properties of the(More)
This paper discusses a new work-scheduling algorithm for parallel search of single-agent state spaces, called Transposition-Table-Driven Work Scheduling, that places the transposition table at the heart of the parallel work scheduling. The scheme results in less synchronization overhead, less processor idle time, and less redundant search effort.(More)
Recent developments in networking technology cause a growing interest in connecting local-area clusters of workstations over wide-area links, creating multilevel clusters. Often, latency and bandwidth differences between local-area and wide-area network links are two orders of magnitude or more. With such a large difference, one would expect only very(More)
The emergence of meta computers and computational grids makes it feasible to run parallel programs on large-scale, geographically distributed computer systems. Writing parallel applications for such systems is a challenging task which may require changes to the communication structure of the applications. MPI’s collective operations (such as broadcast and(More)
We present a new paradigm for minimax search algorithms: MT, a memory-enhanced version of Pearl's Test procedure. By changing the way MT is called, a number of practical best-first search algorithms can be simply constructed. Reformulating SSS* as an instance of MT eliminates all its perceived implementation drawbacks. Most assessments of minimax search(More)