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Parallel Priority Queue and List Contraction: The BSP Approach
 In Proc. EuroPar 97. LNCS
, 1997
"... . In this paper we present efficient and practical extensions of the randomized Parallel Priority Queue (PPQ) algorithms of Ranade et al., and efficient randomized and deterministic algorithms for the problem of list contraction on the BulkSynchronous Parallel (BSP) model. We also present an experi ..."
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. In this paper we present efficient and practical extensions of the randomized Parallel Priority Queue (PPQ) algorithms of Ranade et al., and efficient randomized and deterministic algorithms for the problem of list contraction on the BulkSynchronous Parallel (BSP) model. We also present an experimental study of their performance. We show that our algorithms are communication efficient and achieve small multiplicative constant factors for a wide range of parallel machines. 1 Introduction We present an architecture independent study of the computation and communication requirements of an efficient Parallel Priority Queue (PPQ) implementation and list contraction algorithms along with an experimental study. The computational model adopted is the BulkSynchronous Parallel (BSP) model, proposed by L. G. Valiant [20], which deals explicitly with the notion of communication and synchronization among computational threads. A detailed discussion of the BSP model appears in [20]. The first a...
Optimal Algorithms for the Single and Multiple Vertex Updating Problems of a Minimum Spanning Tree
 Algorithmica
, 1996
"... The vertex updating problem for a minimum spanning tree (MST) is defined as follows: Given a graph G = (V; EG ) and an MST T for G, find a new MST for G to which a new vertex z has been added along with weighted edges that connect z with the vertices of G. We present a set of rules that produce sim ..."
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The vertex updating problem for a minimum spanning tree (MST) is defined as follows: Given a graph G = (V; EG ) and an MST T for G, find a new MST for G to which a new vertex z has been added along with weighted edges that connect z with the vertices of G. We present a set of rules that produce simple optimal parallel algorithms that run in O(lg n) time using n= lg n EREW PRAM processors, where n = jV j. These algorithms employ any valid treecontraction schedule that can be produced within the stated resource bounds. These rules can also be used to derive simple lineartime sequential algorithms for the same problem. The previously best known parallel result was a rather complicated algorithm that used n processors in the more powerful CREW PRAM model. Furthermore, we show how our solution can be used to solve the multiple vertex updating problem: Update a given MST when k new vertices are introduced simultaneously. This problem is solved in O(lg k \Delta lg n) parallel time using ...
Optimal algorithms for the vertex updating problem of a minimum spanning tree
 In Proc. of the 6th Intl Parallel Proccessing Symposium (IPPS '92
, 1992
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AreaEfficient Algorithms for Upward StraightLine Tree Drawings (Extended Abstract)
 in: Proc. COCOON â€˜96
, 1996
"... ) ChanSu Shin 1 and Sung Kwon Kim 2 and KyungYong Chwa 1 1 Dept. of Computer Science, Korea Advanced Institute of Science and Technology, Taejon 305701, Korea, fcssin, kychwag@jupiter.kaist.ac.kr. 2 Dept. of Computer Science and Engineering, ChungAng University, Seoul 156756, Korea, ..."
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) ChanSu Shin 1 and Sung Kwon Kim 2 and KyungYong Chwa 1 1 Dept. of Computer Science, Korea Advanced Institute of Science and Technology, Taejon 305701, Korea, fcssin, kychwag@jupiter.kaist.ac.kr. 2 Dept. of Computer Science and Engineering, ChungAng University, Seoul 156756, Korea, ksk@point.cse.cau.ac.kr. Abstract. In this paper, we investigate planar upward straightline grid drawing problems for boundeddegree rooted trees so that a drawing takes up as little area as possible. A planar upward straightline grid tree drawing satisfies the following four constraints: (1) all vertices are placed at distinct grid points (grid ), (2) all edges are drawn as straight lines (straightline ), (3) no two edges in the drawing intersect (planar ), and (4) no parents are placed below their children (upward ). Our results are summarized as follows. First, we show that a boundeddegree tree T with n vertices admits an upward straightline drawing with area O(n log log n...
Towards polytypic parallel programming
, 1998
"... Data parallelism is currently one of the most successful models for programming massively parallel computers. The central idea is to evaluate a uniform collection of data in parallel by simultaneously manipulating each data element in the collection. Despite many of its promising features, the curre ..."
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Data parallelism is currently one of the most successful models for programming massively parallel computers. The central idea is to evaluate a uniform collection of data in parallel by simultaneously manipulating each data element in the collection. Despite many of its promising features, the current approach suffers from two problems. First, the main parallel data structures that most data parallel languages currently support are restricted to simple collection data types like lists, arrays or similar structures. But other useful data structures like trees have not been well addressed. Second, parallel programming relies on a set of parallel primitives that capture parallel skeletons of interest. However, these primitives are not well structured, and efficient parallel programming with these primitives is difficult. In this paper, we propose a polytypic framework for developing efficient parallel programs on most data structures. We showhow a set of polytypic parallel primitives can be formally defined for manipulating most data structures, how these primitives can be successfully structured into a uniform recursive definition, and how an efficient combination of primitives can be derived from a naive specification program. Our framework should be significant not only in development of new parallel algorithms, but also in construction of parallelizing compilers.
Technical Report No. 2001445 Locating The Median Of A Tree In Real Time
, 2001
"... Determining the optimal location of a switching center in a tree network of users is accurately modeled by the median problem. A realtime approach is used in this paper to investigate the dynamics of such a communication network in two cases: (1) a growing tree of nodes associated with equal demand ..."
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Determining the optimal location of a switching center in a tree network of users is accurately modeled by the median problem. A realtime approach is used in this paper to investigate the dynamics of such a communication network in two cases: (1) a growing tree of nodes associated with equal demand rates, and (2) a stream of corrections that arbitrarily change the demand rates at the nodes. The worstcase analysis performed in both situations clearly demonstrates the importance of parallelism in such realtime paradigms. It is shown that the error generated by the best sequential algorithm in the rst case can be arbitrarily large. A synergistic behavior is revealed when the qualityup is investigated in the second case. 1
by Abstract Devices]: Modes of Computationâ€”parallelism and concurrency
"... Abstract. We define the notion of a wellseparated pair decomposition of points in ddimensional space. We then develop efficient sequential and parallel algorithms for computing such a decomposition. We apply the resulting decomposition to the efficient computation of knearest neighbors and nbody ..."
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Abstract. We define the notion of a wellseparated pair decomposition of points in ddimensional space. We then develop efficient sequential and parallel algorithms for computing such a decomposition. We apply the resulting decomposition to the efficient computation of knearest neighbors and nbody potential fields.
Optimal Tree Contraction and Term Matching on the . . .
, 1995
"... An optimal tree contraction algorithm for the boolean hypercube and the constant degree hypercubic networks, such as the shuffle exchange or the butterfly network, is presented. The algorithm is based on novel routing techniques and, for certain small subtrees, simulates optimal PRAM algorithms. ..."
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An optimal tree contraction algorithm for the boolean hypercube and the constant degree hypercubic networks, such as the shuffle exchange or the butterfly network, is presented. The algorithm is based on novel routing techniques and, for certain small subtrees, simulates optimal PRAM algorithms. For trees of size n, stored on a p processor hypercube in inorder, the running time of the algorithm log p). The resulting speedup of O(p= log p) is optimal due to logarithmic communication overhead, as shown by a corresponding lower bound. The same