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23
A HubBased Labeling Algorithm for Shortest Paths on Road Networks
, 2010
"... Abstract. Abraham et al. [SODA 2010] have recently presented a theoretical analysis of several practical pointtopoint shortest path algorithms based on modeling road networks as graphs with low highway dimension. They also analyze a labeling algorithm. While no practical implementation of this a ..."
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Cited by 48 (17 self)
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Abstract. Abraham et al. [SODA 2010] have recently presented a theoretical analysis of several practical pointtopoint shortest path algorithms based on modeling road networks as graphs with low highway dimension. They also analyze a labeling algorithm. While no practical implementation of this algorithm existed, it has the best time bounds. This paper describes an implementation of the labeling algorithm that is faster than any existing method on continental road networks. 1
TimeDependent Route Planning
 Robust and Online LargeScale Optimization, LNCS
, 2009
"... Abstract. In this paper, we present an overview over existing speedup techniques for timedependent route planning. Apart from only explaining each technique one by one, we follow a more systematic approach. We identify basic ingredients of these recent techniques and show how they need to be augmen ..."
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Cited by 44 (17 self)
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Abstract. In this paper, we present an overview over existing speedup techniques for timedependent route planning. Apart from only explaining each technique one by one, we follow a more systematic approach. We identify basic ingredients of these recent techniques and show how they need to be augmented to guarantee correctness in timedependent networks. With the ingredients adapted, three efficient speedup techniques can be set up: CoreALT, SHARC, and Contraction Hierarchies. Experiments on realworld data deriving from road networks and public transportation confirm that these techniques allow the fast computation of timedependent shortest paths. 1
Engineering Multilevel Graph Partitioning Algorithms
"... We present a multilevel graph partitioning algorithm using novel local improvement algorithms and global search strategies transferred from multigrid linear solvers. Local improvement algorithms are based on maxflow mincut computations and more localized FM searches. By combining these technique ..."
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Cited by 31 (16 self)
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We present a multilevel graph partitioning algorithm using novel local improvement algorithms and global search strategies transferred from multigrid linear solvers. Local improvement algorithms are based on maxflow mincut computations and more localized FM searches. By combining these techniques, we obtain an algorithm that is fast on the one hand and on the other hand is able to improve the best known partitioning results for many inputs. For example, in Walshaw’s well known benchmark tables we achieve 317 improvements for the tables at 1%, 3 % and 5 % imbalance. Moreover, in 118 out of the 295 remaining cases we have been able to reproduce the best cut in this benchmark.
Distributed Evolutionary Graph Partitioning
, 2012
"... We present a novel distributed evolutionary algorithm, KaFFPaE, to solve the Graph Partitioning Problem, which makes use of KaFFPa (Karlsruhe Fast Flow Partitioner). The use of our multilevel graph partitioner KaFFPa provides new effective crossover and mutation operators. By combining these with a ..."
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Cited by 27 (13 self)
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We present a novel distributed evolutionary algorithm, KaFFPaE, to solve the Graph Partitioning Problem, which makes use of KaFFPa (Karlsruhe Fast Flow Partitioner). The use of our multilevel graph partitioner KaFFPa provides new effective crossover and mutation operators. By combining these with a scalable communication protocol we obtain a system that is able to improve the best known partitioning results for many inputs in a very short amount of time. For example, in Walshaw’s well known benchmark tables we are able to improve or recompute 76 % of entries for the tables with 1%, 3 % and 5 % imbalance.
PHAST: hardwareaccelerated shortest path trees
 J. PARALLEL DISTRIB. COMPUT
, 2013
"... We present a novel algorithm to solve the nonnegative singlesource shortest path problem on road networks and graphs with low highway dimension. After a quick preprocessing phase, we can compute all distances from a given source in the graph with essentially a linear sweep over all vertices. Becaus ..."
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Cited by 20 (4 self)
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We present a novel algorithm to solve the nonnegative singlesource shortest path problem on road networks and graphs with low highway dimension. After a quick preprocessing phase, we can compute all distances from a given source in the graph with essentially a linear sweep over all vertices. Because this sweep is independent of the source, we are able to reorder vertices in advance to exploit locality. Moreover, our algorithm takes advantage of features of modern CPU architectures, such as SSE and multiple cores. Compared to Dijkstra’s algorithm, our method needs fewer operations, has better locality, and is better able to exploit parallelism at multicore and instruction levels. We gain additional speedup when implementing our algorithm on a GPU, where it is up to three orders of magnitude faster than Dijkstra’s algorithm on a highend CPU. This makes applications based on allpairs shortestpaths practical for continentalsized road networks. Several algorithms, such as computing the graph diameter, arc flags, or exact reaches, can be greatly accelerated by our method.
Faster Customization of Road Networks
 In Proc. SEA, LNCS
, 2013
"... Abstract. A wide variety of algorithms can answer exact shortestpath queries in real time on continental road networks, but they typically require significant preprocessing effort. Recently, the customizable route planning (CRP) approach has reduced the time to process a new cost function to a frac ..."
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Cited by 15 (5 self)
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Abstract. A wide variety of algorithms can answer exact shortestpath queries in real time on continental road networks, but they typically require significant preprocessing effort. Recently, the customizable route planning (CRP) approach has reduced the time to process a new cost function to a fraction of a minute. We reduce customization time even further, by an order of magnitude. This makes it worthwhile even when a single query is to be run, enabling a host of new applications. 1
High quality graph partitioning
, 2013
"... We present an overview over our graph partitioners KaFFPa (Karlsruhe Fast Flow Partitioner) and KaFFPaE (KaFFPa Evolutionary). KaFFPa is a multilevel graph partitioning algorithm which on the one hand uses novel local improvement algorithms based on maxflow and mincut computations and more local ..."
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Cited by 9 (6 self)
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We present an overview over our graph partitioners KaFFPa (Karlsruhe Fast Flow Partitioner) and KaFFPaE (KaFFPa Evolutionary). KaFFPa is a multilevel graph partitioning algorithm which on the one hand uses novel local improvement algorithms based on maxflow and mincut computations and more localized FM searches and on the other hand uses more sophisticated global search strategies transferred from multigrid linear solvers. KaFFPaE is a distributed evolutionary algorithm to solve the Graph Partitioning Problem. KaFFPaE uses KaFFPa and provides new effective crossover and mutation operators. By combining these with a scalable communication protocol we obtain a system that is able to improve the best known partitioning results for many inputs.
Exact Combinatorial BranchandBound for Graph Bisection
"... We present a novel exact algorithm for the minimum graph bisection problem, whose goal is to partition a graph into two equallysized cells while minimizing the number of edges between them. Our algorithm is based on the branchandbound framework and, unlike most previous approaches, it is fully co ..."
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Cited by 7 (3 self)
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We present a novel exact algorithm for the minimum graph bisection problem, whose goal is to partition a graph into two equallysized cells while minimizing the number of edges between them. Our algorithm is based on the branchandbound framework and, unlike most previous approaches, it is fully combinatorial. We present stronger lower bounds, improved branching rules, and a new decomposition technique that contracts entire regions of the graph without losing optimality guarantees. In practice, our algorithm works particularly well on instances with relatively small minimum bisections, solving large realworld graphs (with tens of thousands to millions of vertices) to optimality.
TRANSIT Routing on Video Game Maps
"... TRANSIT (Bast, Funke, and Matijevic 2006) is a fast and optimal technique for computing shortest path costs in road networks. It is attractive for its usually modest memory requirements and impressive running times. In this paper we give a first analysis of TRANSIT routing on a set of popular gridb ..."
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Cited by 5 (2 self)
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TRANSIT (Bast, Funke, and Matijevic 2006) is a fast and optimal technique for computing shortest path costs in road networks. It is attractive for its usually modest memory requirements and impressive running times. In this paper we give a first analysis of TRANSIT routing on a set of popular gridbased videogame benchmarks taken from the AI pathfinding literature. We show that in the presence of path symmetries, which are inherent to most grids but normally not road networks, TRANSIT is strongly and negatively impacted, both in terms of performance and memory requirements. We address this problem by developing a new general symmetry breaking technique which adds small random ɛvalues to edges in the search graph, reducing the size of the TRANSIT network by up to 4 times while preserving optimality. Using our enhancements TRANSIT achieves up to four orders of magnitude speed improvement vs. A * search and uses in many cases only a small ( ≤ 10MB) or modest ( ≤ 50MB) amount of memory. We also compare TRANSIT with CPDs, a recent and very fast databasedriven pathfinding approach. We find the algorithms have complementary strengths but also identify a class of problems for which TRANSIT is up to two orders of magnitude faster than CPDs using a comparable amount of memory.
Approximating the Smallest 2Vertex Connected Spanning Subgraph of a Directed Graph?
"... Abstract. We consider the problem of approximating the smallest 2vertex connected spanning subgraph (2VCSS) of a 2vertex connected directed graph, and explore the efficiency of fast heuristics. First, we present a lineartime heuristic that gives a 3approximation of the smallest 2VCSS. Then we ..."
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Cited by 4 (2 self)
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Abstract. We consider the problem of approximating the smallest 2vertex connected spanning subgraph (2VCSS) of a 2vertex connected directed graph, and explore the efficiency of fast heuristics. First, we present a lineartime heuristic that gives a 3approximation of the smallest 2VCSS. Then we show that this heuristic can be combined with an algorithm of Cheriyan and Thurimella that achieves a (1 + 1/k)approximation of the smallest kVCSS. The combined algorithm preserves the 1.5 approximation guarantee of the CheriyanThurimella algorithm for k = 2 and improves its running time from O(m2) to O(m n+ n2), for a digraph with n vertices and m arcs. Finally, we present an experimental evaluation of the above algorithms for a variety of input data. The experimental results show that our lineartime heuristic achieves in practice a much better approximation ratio than 3, suggesting that a tighter analysis may be possible. Furthermore, the experiments show that the combined algorithm not only improves the running time of the CheriyanThurimella algorithm, but it may also compute a smaller 2VCSS. 1