This paper presents an efficient parallel algorithm for the shortest-path problem in interval graph for computing shortest-paths in a weighted interval graph that runs in O(n) time with n intervals in a graph. A linea...
详细信息
This paper presents an efficient parallel algorithm for the shortest-path problem in interval graph for computing shortest-paths in a weighted interval graph that runs in O(n) time with n intervals in a graph. A linear processor CRCW algorithm for determining the shortest-paths in an interval graphs is given.
The problem of solving tridiagonal linear systems on parallel distributed-memory environments is considered in this paper. In particular, two common direct methods for solving such systems are considered: odd-even cyc...
详细信息
The problem of solving tridiagonal linear systems on parallel distributed-memory environments is considered in this paper. In particular, two common direct methods for solving such systems are considered: odd-even cyclic reduction and prefix summing. For each method, a variety of lower bounds on execution time for solving tridiagonal linear systems are presented. Specifically, lower bounds are presented that (a) hold when the number of data items per processor is bounded, (b) are general lower bounds, and (c) for specific data layouts commonly used in designing parallel algorithms to solve tridiagonal linear systems. Furthermore, algorithms are presented that have running times within a constant factor of the lower bounds provided. Lastly, a comparison of bounds for odd-even cyclic reduction and prefix summing is given.
In this paper we study scheduling algorithms in WDM optical interconnects with recirculating buffering. The interconnect we consider has wavelength conversion capabilities. We focus on limited range wavelength convers...
详细信息
ISBN:
(纸本)0769521975
In this paper we study scheduling algorithms in WDM optical interconnects with recirculating buffering. The interconnect we consider has wavelength conversion capabilities. We focus on limited range wavelength conversion while considering full range wavelength conversion as a special case. We formalize the problem of maximizing throughput and minimizing packet delay in such an interconnect as a matching problem in a bipartite graph and give an optimal parallel algorithm that runs in O(Bk-2), as compared to O((N + B)(3)k(3)) time if directly applying other existing matching algorithms, where N is the number of input/output fibers, B is the number of fiber delay lines and k is the number of wavelengths per fiber.
In here we consider the problem of parallel execution of Join operation by a J2EE cluster. J2EE clusters are intended for coarse-grain distributed processing of multiple queries/business transactions over the Web. Thu...
详细信息
ISBN:
(纸本)0769522106
In here we consider the problem of parallel execution of Join operation by a J2EE cluster. J2EE clusters are intended for coarse-grain distributed processing of multiple queries/business transactions over the Web. Thus, the possiblity of using it J2EE cluster for fine-grain parallel computations (parallel Joins in our case) is intriguing and of practical interest. We have developed a new variant of the SFR algorithm for parallel computation of Cartesian Product in Join operations and proved its optimality in terms of communication/execution-time tradeoffs via a simple lower bound. Our experimental results show that despite the fact that J2EE is considered to be a platform that uses a complex interfaces and software entities, such as various types of Java beans, J2EE clusters can be efficiently used to execute Join operation in parallel.
We have developed a coarse-grain parallelization of the Buchberger algorithm for computing Grobner bases in algebras of linear differential operators. The implementation of this algorithm provides good speedups on the...
详细信息
ISBN:
(纸本)0769521983
We have developed a coarse-grain parallelization of the Buchberger algorithm for computing Grobner bases in algebras of linear differential operators. The implementation of this algorithm provides good speedups on the majority of examples coming from these noncommutative algebras, which are superior to the speedups achieved for (commutative) polynomial rings.
A management configuration refers to an arrangement of management agents across a distributed system whose tasks are to monitor and control system components to ensure efficient use of resources and timely services to...
详细信息
ISBN:
(纸本)1932415262
A management configuration refers to an arrangement of management agents across a distributed system whose tasks are to monitor and control system components to ensure efficient use of resources and timely services to users. These management activities can degrade system performance due to the resources consumed by management agents, e.g. CPU, memory, network bandwidth, storage space, etc. A good configuration of management agents is needed to minimize the impact on system performance. Previous work on determining efficient management configurations proposed a branch-and-bound based algorithm for finding a good configuration. The performance of that algorithm can be unacceptable even for moderately sized systems. A parallel version of that algorithm has been developed. This paper reports on an implementation and experiments evaluating the effectiveness of that algorithm.
Concept Lattice, the core data structure in Formal Concept Analysis, has been used widely in machine learning, data mining and knowledge discovery, information retrieval, etc. The main difficulty with concept lattice-...
详细信息
ISBN:
(纸本)0769521525
Concept Lattice, the core data structure in Formal Concept Analysis, has been used widely in machine learning, data mining and knowledge discovery, information retrieval, etc. The main difficulty with concept lattice-based system comes from the lattice construction itself In this paper, a parallel algorithm based on the closure search space partition for computing concepts is proposed. This algorithm divides the closure search space into several subspaces in accordance with criterions prescribed ahead and introduces an efficient scheme to recognize the valid ones, in which the searching for closures is bounded An intermediate structure is employed to judge the validity of a subspace and compute closures more efficiently. Since the searching in subspaces are independent tasks, a parallel algorithm based on search space partition can be directly reached.
In this paper special attention is devoted to one particular problem, the diffusion equation subject to the specification of mass in a portion of the domain, which has been studied quite extensively, both analytically...
详细信息
In this paper special attention is devoted to one particular problem, the diffusion equation subject to the specification of mass in a portion of the domain, which has been studied quite extensively, both analytically and numerically, in recent years. Parabolic partial differential equations with a non-local constraint in place of one of the standard boundary specifications feature in the mathematical modeling of many phenomena. In this paper the application of the method of lines (MOL) to such problems is considered. The MOL semi-discretization approach will be used to transform the model partial differential equation into a system of first-order linear ordinary differential equations (ODES). The MOL is a method of solving PDEs by discretizing the equation with respect to all but one variable (usually time). The spatial partial derivative is approximated by a finite-difference method. The solution of the resulting system of first-order ODEs satisfies a recurrence relation which involves a matrix exponential function. Numerical techniques are developed by approximating the exponential matrix function in this recurrence relation. The matrix exponential function is approximated by a rational approximation consisting of four parameters. New parallel algorithms are developed using the resulting approximation. Numerical experiments on two challenging examples are presented to illustrate the performance of the algorithms. (C) 2003 Elsevier Inc. All rights reserved.
A key ingredient of finite-element analysis programs is the linear-algebra solver, typically either a linear-system solver or an eigensolver. The first part of this paper tries to justify why it is important to have r...
详细信息
A key ingredient of finite-element analysis programs is the linear-algebra solver, typically either a linear-system solver or an eigensolver. The first part of this paper tries to justify why it is important to have recourse to publicly available software for addressing this part of the computation. A number of libraries are mentioned as successful examples that exhibit a series of desirable qualities. Although some of these libraries force the programmer to somewhat change the programming style and may be difficult to learn, the benefits usually pay off the extra effort. The second part of the paper describes one of these libraries in some detail, namely SLEPc, the Scalable Library for Eigenvalue Problem Computations, which is used to illustrate the benefits of modern software paradigms for scientific and engineering computing.
Using orthogonal localized occupied orbitals we have developed and implemented a parallelized local second-order Moller-Plesset (MP2) method based on the idea developed by Head-Gordon and co-workers. A subset of nonor...
详细信息
Using orthogonal localized occupied orbitals we have developed and implemented a parallelized local second-order Moller-Plesset (MP2) method based on the idea developed by Head-Gordon and co-workers. A subset of nonorthogonal correlation functions (the orbital domain) was assigned to each of the localized occupied orbitals using a distance criterion and excitations from localized occupied orbitals that were arranged into subsets. The correlation energy was estimated using a partial diagonalization and an iterative efficient method for solving large-scale linear equations. Some illustrative calculations are provided for molecules with up to 1484 Cartesian basis sets. The orbital domain sizes were found to be independent of the molecular size, and the present local MP2 method covered about 98%-99% of the correlation energy of the conventional canonical MP2 method. (C) 2004 American Institute of Physics.
暂无评论