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62
HeavyTailed Phenomena in Satisfiability and Constraint Satisfaction Problems
 J. of Autom. Reasoning
, 2000
"... Abstract. We study the runtime distributions of backtrack procedures for propositional satisfiability and constraint satisfaction. Such procedures often exhibit a large variability in performance. Our study reveals some intriguing properties of such distributions: They are often characterized by ver ..."
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Cited by 148 (27 self)
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Abstract. We study the runtime distributions of backtrack procedures for propositional satisfiability and constraint satisfaction. Such procedures often exhibit a large variability in performance. Our study reveals some intriguing properties of such distributions: They are often characterized by very long tails or “heavy tails”. We will show that these distributions are best characterized by a general class of distributions that can have infinite moments (i.e., an infinite mean, variance, etc.). Such nonstandard distributions have recently been observed in areas as diverse as economics, statistical physics, and geophysics. They are closely related to fractal phenomena, whose study was introduced by Mandelbrot. We also show how random restarts can effectively eliminate heavytailed behavior. Furthermore, for harder problem instances, we observe long tails on the lefthand side of the distribution, which is indicative of a nonnegligible fraction of relatively short, successful runs. A rapid restart strategy eliminates heavytailed behavior and takes advantage of short runs, significantly reducing expected solution time. We demonstrate speedups of up to two orders of magnitude on SAT and CSP encodings of hard problems in planning, scheduling, and circuit synthesis. Key words: satisfiability, constraint satisfaction, heavy tails, backtracking 1.
Dijkstra's Algorithm OnLine: An Empirical Case Study from Public Railroad Transport
 JOURNAL OF EXPERIMENTAL ALGORITHMICS
, 2000
"... ..."
PROTOMOL, an ObjectOriented Framework for Prototyping Novel Algorithms for Molecular Dynamics
 In Computational Science—ICCS 2003, International Conference
, 2002
"... Factory [Gamma et al. 1995, pp. 8795] and the Prototype [Gamma et al. 1995, pp. 117126] patterns. The Abstract Factory pattern delegates the object creation, and the Prototype pattern allows dynamic configuration. The factory is in charge of converting the userspecified force into an object that ..."
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Cited by 22 (15 self)
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Factory [Gamma et al. 1995, pp. 8795] and the Prototype [Gamma et al. 1995, pp. 117126] patterns. The Abstract Factory pattern delegates the object creation, and the Prototype pattern allows dynamic configuration. The factory is in charge of converting the userspecified force into an object that has been properly setup to do computation. The factory creates replicas of "prototypes" that have been registered by the developer. This restricts the factory to create only supported objects, since not all combinations of R1R5 make sense or are supported at a given stage of development.
A Systematic Review of the Application and Empirical Investigation of Searchbased TestCase Generation
, 2008
"... Metaheuristic search techniques have been extensively used to automate the process of generating test cases and thus providing solutions for a more costeffective testing process. This approach to test automation, often coined as “Searchbased Software Testing” (SBST), has been used for a wide varie ..."
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Cited by 21 (5 self)
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Metaheuristic search techniques have been extensively used to automate the process of generating test cases and thus providing solutions for a more costeffective testing process. This approach to test automation, often coined as “Searchbased Software Testing” (SBST), has been used for a wide variety of test case generation purposes. Since SBST techniques are heuristic by nature, they must be empirically investigated in terms of how costly and effective they are at reaching their test objectives and whether they scale up to realistic development artifacts. However, approaches to empirically study SBST techniques have shown wide variation in the literature. This paper presents the results of a systematic, comprehensive review that aims at characterizing how empirical studies have been designed to investigate SBST costeffectiveness and what empirical evidence is available in the literature regarding SBST costeffectiveness and scalability. We also provide a framework that drives the data collection process of this systematic review and can be the starting point of guidelines on how SBST techniques can be empirically assessed. The intent is to aid future researchers doing empirical studies in SBST by providing an unbiased view of the body of empirical evidence and by guiding them in performing well designed and executed empirical studies references.
A New Algorithm For The MaximumWeight Clique Problem
"... Given a graph, in the maximum clique problem one wants to find the largest number of vertices, any two of which are adjacent. In the maximumweight clique problem, the vertices have positive, integer weights, and one wants to find a clique with maximum weight. A recent algorithm for the maximum cliq ..."
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Cited by 19 (0 self)
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Given a graph, in the maximum clique problem one wants to find the largest number of vertices, any two of which are adjacent. In the maximumweight clique problem, the vertices have positive, integer weights, and one wants to find a clique with maximum weight. A recent algorithm for the maximum clique problem is here used as a basis for developing an algorithm for the weighted case. Computational experiments with random graphs show that this new algorithm is faster than earlier algorithms in many cases. A set of weighted graphs obtained from the problem of constructing good constant weight errorcorrecting codes are proposed as test cases for maximumweight clique algorithms
How Not To Do It
, 1997
"... We give some dos and don'ts for those analysing algorithms experimentally. We illustrate these with many examples from our own research on the study of algorithms for NPcomplete problems such as satisfiability and constraint satisfaction. Where we have not followed these maxims, we have suffered as ..."
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Cited by 14 (1 self)
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We give some dos and don'ts for those analysing algorithms experimentally. We illustrate these with many examples from our own research on the study of algorithms for NPcomplete problems such as satisfiability and constraint satisfaction. Where we have not followed these maxims, we have suffered as a result. 1 Introduction The empirical study of algorithms is a relatively immature field with many technical and scientific problems. We support the calls of McGeoch (1986,1996), Hooker (1994), and others for a more scientific approach to the empirical study of algorithms. Our contribution in this paper is colloquial. We admit to a large number of mistakes in conducting our research. While painful, we hope that this will encourage others to avoid these mistakes, and thereby to develop practices which represent good science. Much of our research has been on the experimental analysis of algorithms and phase transitions in NPcomplete problems, most commonly in satisfiability or constraint s...
Design and results of tancs2000 nonclassical (modal) systems comparison
 In TABLEAUX ’00: Proceedings of the International Conference on Automated Reasoning with Analytic Tableaux and Related Methods
, 2000
"... Abstract. The aim of the TABLEAUX2000 NonClassical (Modal) System Comparisons (TANCS2000) is to provide a set of benchmarks and a standardized methodology for the assessment and comparison of ATP systems in nonclassical logics, as it is done for firstorder logic with the CADE System Competition ..."
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Cited by 12 (0 self)
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Abstract. The aim of the TABLEAUX2000 NonClassical (Modal) System Comparisons (TANCS2000) is to provide a set of benchmarks and a standardized methodology for the assessment and comparison of ATP systems in nonclassical logics, as it is done for firstorder logic with the CADE System Competition. We believe that TANCS can benefit the scientific community in two ways: by promoting the competition among ATP systems and thus yielding novel solutions, and by providing a scientific design for benchmarking nonclassical ATP systems. This paper reports the main ideas behind the design, the benchmarks, the organization, and the rating of the ATP systems of TANCS2000. 1 Design and Organization of the Comparison The first comparison has been held in 1998 [1], a second one has been held in 1999 [11] and this one continues the series with a focus on expressive modal and description logics (for an introduction to modal logics see [7], for description logics see [3]). The following Automated Theorem Proving (ATP) systems have been submitted this year: mspass (based on resolution), ⋆sat, FaCT, dlp and race (based on various optimization of tableaux and DavisPuntam procedures). Their descriptions can be found in these proceedings. As in past years, they have been compared along two yardsticks: effectiveness and usability. Effectiveness can be measured on the basis of the type and number of problems solved, the average runtime for successful solutions, the scaling of the prover as problems gets bigger. Usability can be assessed on the basis of availability via web or other sources, portability to various platforms, need for additional software besides the prover itself, ease of installation and use (e.g., visual interfaces), possibility of customizing the search heuristics, etc. For what regard effectiveness, a sensitive decision is the choice of benchmark problems which should offer the possibility to generate enough different samples More details are at
Rapid mathematical programming
, 2004
"... This book was typeset with TEX using L ATEX and many further formatting packages. The pictures were prepared using pstricks, xfig, gnuplot and gmt. All numerals in this text are recycled. Für meine Eltern Preface Avoid reality at all costs — fortune(6) As the inclined reader will find out soon enoug ..."
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Cited by 10 (2 self)
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This book was typeset with TEX using L ATEX and many further formatting packages. The pictures were prepared using pstricks, xfig, gnuplot and gmt. All numerals in this text are recycled. Für meine Eltern Preface Avoid reality at all costs — fortune(6) As the inclined reader will find out soon enough, this thesis is not about deeply involved mathematics as a mean in itself, but about how to apply mathematics to solve realworld problems. We will show how to shape, forge, and yield our tool of choice to rapidly answer questions of concern to people outside the world of mathematics. But there is more to it. Our tool of choice is software. This is not unusual, since it has become standard practice in science to use software as part of experiments and sometimes even for proofs. But in order to call an experiment scientific it must be reproducible. Is this the case?
DomainIndependent Local Search For Linear Integer Optimization
, 1998
"... Integer and combinatorial optimization problems constitute a major challenge for algorithmics. They arise when a large number of discrete organizational decisions have to be made, subject to constraints and optimization criteria. This thesis ..."
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Cited by 10 (1 self)
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Integer and combinatorial optimization problems constitute a major challenge for algorithmics. They arise when a large number of discrete organizational decisions have to be made, subject to constraints and optimization criteria. This thesis