We present an algorithm for parallel construction of Huffman codes in O(n/√p log p) time with p processors, where p > 1, improving the previous result of Levcopoulos and Przytyrcka. We also show, that a greedy Huf...
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We present an algorithm for parallel construction of Huffman codes in O(n/√p log p) time with p processors, where p > 1, improving the previous result of Levcopoulos and Przytyrcka. We also show, that a greedy Huffman tree can be constructed in O(√n log n) time with n processors.
For a certain class of triangles (with angles proportional to pi/N, Ngreater than or equal to3) we formulate an image method by making use of the group G(N) generated by reflections with respect to the three lines whi...
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For a certain class of triangles (with angles proportional to pi/N, Ngreater than or equal to3) we formulate an image method by making use of the group G(N) generated by reflections with respect to the three lines which form the triangle under consideration. We formulate the regularization procedure by classification of subgroups of G(N) and corresponding fixed points in the triangle. We then also calculate Casimir energy for a cavity of infinite height with triangular cross section for scalar massless fields. More detailed calculation is given for odd N. (C) 2004 American Institute of Physics.
A parenthesis string is a string of left and right parentheses. The string is well-formed when it consists of balanced pairs of left and right parentheses. This study presents a novel systolic algorithm for generating...
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A parenthesis string is a string of left and right parentheses. The string is well-formed when it consists of balanced pairs of left and right parentheses. This study presents a novel systolic algorithm for generating all the well-formed parenthesis strings in lexicographical order. The algorithm is cost-optimal and is run on a linear array of processors such that each well-formed parenthesis string can be generated in three time steps. The processor array is appropriate for VLSI implementation, since it has the features of modularity, regularity, and local connection.
Fast Fourier Transform (FFT) has been used in many scientific and engineering applications. In the current study, we have tried to improve a recently proposed model of FFT for pricing financial derivatives so as to he...
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In this paper we develop a load-adaptive multithreaded algorithm to compute 2D Discrete Wavelet Transform (DWT) and its implementation on a fine-grain multithreading platform. In a 2D DWT computation, the problem size...
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In this paper we develop a load-adaptive multithreaded algorithm to compute 2D Discrete Wavelet Transform (DWT) and its implementation on a fine-grain multithreading platform. In a 2D DWT computation, the problem sizes reduces at every decomposition level and the length of the emerging computation paths also vary. The parallel algorithm proposed in this paper, dynamically scales itself to the varying problem size. During any iteration, the ratio of the number of local threads to the number of remote threads issued by a processor can be adjusted to be greater than I by controlling the algorithm parameters. This approach provides an opportunity to interleave computation and communication without explicitly introducing idle cycles on waiting for the remote threads to finish. Experimental results are reported based on the implementations of the proposed algorithm on a 20 node emulated multithreaded platform, EARTH-MANNA, specifically designed for fine-grain multithreaded paradigms. We show that multithreading implementations of the proposed algorithm are at least 2 times faster than the MPI-based message passing implementations reported in the literature, assuming the same processor speed. We further show that the proposed algorithm and implementations scale linearly with respect to problem and machine sizes. (C) 2003 Elsevier Inc. All rights reserved.
In this paper we propose a novel parallel algorithm for frequent itemset mining. The algorithm is based on the filter-stream programming model, in which the frequent itemset mining process is represented as a data flo...
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Hierarchical agglomerative clustering (HAC) is a common clustering method that outputs a dendrogram showing all N levels of agglomerations where N is the number of objects in the data set. High time and memory complex...
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We show the importance of sequential sorting in the context of in-memory parallel sorting of large data sets of 64-bit keys. First, we analyze several sequential strategies, like Straight Insertion, Quick sort, Radix ...
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ISBN:
(纸本)0769514448
We show the importance of sequential sorting in the context of in-memory parallel sorting of large data sets of 64-bit keys. First, we analyze several sequential strategies, like Straight Insertion, Quick sort, Radix sort and Cache-Conscious Radix sort (CC-Radix sort). As a consequence of the analysis, we propose a new algorithm that we call the Sequential Counting Split Radix sort (SCS-Radix sort). This is a combination of some of the algorithms analyzed and other new ideas. There are three important contributions in SCS-Radix sort: first, the work saved by detecting data skew dynamically; second, the exploitation of the memory hierarchy done by the algorithm; and third, the execution time stability of SCS-Radix when sorting data sets with different characteristics. We evaluate the use of SCS-Radix sort in the context of a parallel sorting algorithm on an SGI Origin 2000. The parallel algorithm is 1.2 to 45 times faster using the SCS-Radix sort than using the Radix sort or Quick sort.
This paper examines the influence of mating restrictions in two parallel genetic algorithms; the island-model, and an alternative which adaptively partitions the search space into separately optimised regions. Mating ...
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This paper examines the influence of mating restrictions in two parallel genetic algorithms; the island-model, and an alternative which adaptively partitions the search space into separately optimised regions. Mating restrictions are found critical in both cases, but particularly the island-model whose performance is only comparable when mating is significantly restricted.
We present parallel algorithms for the following four operations on red-black trees: construction, search, insertion, and deletion. Our parallel algorithm for constructing a red-black tree from a sorted list of n item...
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We present parallel algorithms for the following four operations on red-black trees: construction, search, insertion, and deletion. Our parallel algorithm for constructing a red-black tree from a sorted list of n items runs in O(1) time with n processors on the CRCW PRAM and runs in O(loglogn) time with n/loglogn processors on the EREW PRAM. Our construction algorithm does not require the assumptions that previous construction algorithms used. Each of our parallel algorithms for search, insertion, and deletion in red-black trees runs in O(logn + logk) time with k processors on the EREW PRAM, where k is the number of unsorted items to search for, insert, or delete and n is the number of nodes in a red-black tree. (C) 2001 Elsevier Science B.V. All rights reserved.
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