Several models of parallel disks are found in the literature. These models have been proposed to alleviate the I/O bottleneck arising in handling voluminous data. These models have the general theme of assuming multip...
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Several models of parallel disks are found in the literature. These models have been proposed to alleviate the I/O bottleneck arising in handling voluminous data. These models have the general theme of assuming multiple disks. For instance the parallel disks model assumes D disks and a single computer. It is also assumed that a block of data from each of the D disks can be fetched into the main memory in one parallel I/O operation. In this paper, we study a model where there are more than one processors and each processor has an associated disk. In addition to the I/O cost, one also has to account for the inter-processor communication costs. To begin with we study the mesh and we investigate the performance of the mesh with respect to out-of-core computing. As a case study we consider the problem of sorting. The goal of this paper is to study the properties of this model. (C) 2004 Elsevier Inc. All rights reserved.
We study the complexity of a two-point boundary value problem. We concentrate on the linear problem of order k with separated boundary conditions. Right-hand side functions are assumed to be r times differentiable wit...
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We study the complexity of a two-point boundary value problem. We concentrate on the linear problem of order k with separated boundary conditions. Right-hand side functions are assumed to be r times differentiable with all derivatives bounded by a constant. We consider three models of computation: deterministic with standard and linear information, randomized and quantum. In each setting, we construct an algorithm for solving the problem, which allows us to establish upper complexity bounds. In the deterministic setting, we show that the use of linear information gives us a speed-up of at least one order of magnitude compared with the standard information. For randomized algorithms, we show that the speed-up over standard deterministic algorithms is by 1/2 in the exponent. For quantum algorithms, we can achieve a speed-up by one order of magnitude. We also provide lower complexity bounds. They match upper bounds in the deterministic setting with the standard information, and almost match upper bounds in the randomized and quantum settings. In the deterministic setting with the linear information, a gap still remains between the upper and lower complexity bounds.
We deal with the complexity of nonlinear BVPs with nonlinear two-point boundary conditions. We consider the randomized and quantum models of computation. We assume that the right-hand side function is r times differen...
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We deal with the complexity of nonlinear BVPs with nonlinear two-point boundary conditions. We consider the randomized and quantum models of computation. We assume that the right-hand side function is r times differentiable with all derivatives bounded by a constant. We show that the epsilon-complexity is roughly of order epsilon(-1/(r+1/2)) in the randomized setting, and epsilon(-1/(r+1)) in the quantum setting. We compare our results with known results in the deterministic setting. The speed-up of the randomized computations with respect to the deterministic computations is by 1/(r(2r + 1)) in the exponent of 1/epsilon, and the speed-up of the quantum computations by 1/(r(r +1)) in the exponent. (C) 2014 Elsevier Inc. All rights reserved.
We discuss several complexity measures for Boolean functions: certificate complexity, sensitivity, block sensitivity, and the degree of a representing or approximating polynomial. We survey the relations and biggest g...
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We discuss several complexity measures for Boolean functions: certificate complexity, sensitivity, block sensitivity, and the degree of a representing or approximating polynomial. We survey the relations and biggest gaps known between these measures, and show how they give bounds for the decision tree complexity of Boolean functions on deterministic, randomized, and quantum computers. (C) 2002 Elsevier Science B.V. All rights reserved.
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