This paper presents experiences using Intel's KNL MIC platform on hardware that will be available in the Stampede 2 cluster launching in Summer 2017. We focus on 1) porting of existing scientific software;2) obser...
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methods for the minimal-norm bandlimited interpolation of nonuniform samples are known to have serious numerical issues even though this interpolation is mathematically well defined. Moreover, they have been formulate...
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ISBN:
(纸本)9781538615652
methods for the minimal-norm bandlimited interpolation of nonuniform samples are known to have serious numerical issues even though this interpolation is mathematically well defined. Moreover, they have been formulated only for finite numbers of samples. By a rigorous revisit of this problem from an operator-theoretic viewpoint in Hilbert spaces, we devise an algorithm for this interpolation that applies to an infinite number of samples with no condition, with guaranteed stability at least for finite numbers of samples, and with a recursive part that can be rigorously implemented in discrete time.
We propose efficient methods for the numerical approximation of the field of values of the linear pencil A − λB, when one of the matrix coefficients A or B is Hermitian and λ ∈ ℂ. Our approach builds on the fact th...
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This paper studies a low-communication algorithm for solving elliptic PDEs on high-performance machines, the nested iteration with range decomposition (NIRD) algorithm. Previous work has shown that NIRD converges to a...
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This paper studies a low-communication algorithm for solving elliptic PDEs on high-performance machines, the nested iteration with range decomposition (NIRD) algorithm. Previous work has shown that NIRD converges to a high level of accuracy within a small, fixed number of iterations (usually one or two) when applied to simple elliptic problems. This paper makes some improvements to the NIRD algorithm (including the addition of adaptivity during preprocessing, wider choice of partitioning functions, and modified error measurement) that enhance the method's accuracy and scalability, especially on more difficult problems. In addition, an updated convergence proof is presented based on heuristic assumptions that are supported by numerical evidence. Furthermore, a new performance model is developed that shows increased performance benefits for NIRD when problems are more expensive to solve using traditional methods. Finally, extensive testing on a variety of elliptic problems provides additional insight into the behavior of NIRD and additional evidence that NIRD achieves excellent convergence on a wide class of elliptic PDEs and, as such, should be a very competitive method for solving PDEs on large parallel computers.
Sparsity has been widely recognized as crucial for efficient optimization in graph-based SLAM. Because the sparsity and structure of the SLAM graph reflect the set of incorporated measurements, many methods for sparsi...
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Sparsity has been widely recognized as crucial for efficient optimization in graph-based SLAM. Because the sparsity and structure of the SLAM graph reflect the set of incorporated measurements, many methods for sparsification have been proposed in hopes of reducing computation. These methods often focus narrowly on reducing edge count without regard for structure at a global level. Such structurally-naive techniques can fail to produce significant computational savings, even after aggressive pruning. In contrast, simple heuristics such as measurement decimation and keyframing are known empirically to produce significant computation reductions. To demonstrate why, we propose a quantitative metric called elimination complexity (EC) that bridges the existing analytic gap between graph structure and computation. EC quantifies the complexity of the primary computational bottleneck: the factorization step of a Gauss-Newton iteration. Using this metric, we show rigorously that decimation and keyframing impose favorable global structures and therefore achieve computation reductions on the order of r~2/9 and r~3, respectively, where r is the pruning rate. We additionally present numerical results showing EC provides a good approximation of computation in both batch and incremental (iSAM2) optimization and demonstrate that pruning methods promoting globally-efficient structure outperform those that do not.
It is well known that the biconjugate residual (BCR) algorithm and its variants are powerful procedures to find the solution of large sparse non-symmetric systems equation. In this study, the authors develop the Lancz...
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It is well known that the biconjugate residual (BCR) algorithm and its variants are powerful procedures to find the solution of large sparse non-symmetric systems equation. In this study, the authors develop the Lanczos version of BCR algorithm for computing the solution pair of the generalised second-order Sylvester matrix equation EVF + GVH + BVC = DWE + M which includes the second-order Sylvester, Lyapunov and Stein matrix equations as special cases. The convergence results show that the algorithm with any initial matrices converges to the solutions within a finite number of iterations in the absence of round-off errors. Finally, two numerical examples are provided to support the theoretical findings and to testify the effectiveness and usefulness of the algorithm.
For the accurate representation and reconstruction of band-limited signals on the sphere, an optimal-dimensionality sampling scheme has been recently proposed which requires the optimal number of samples equal to the ...
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ISBN:
(纸本)9781538615652
For the accurate representation and reconstruction of band-limited signals on the sphere, an optimal-dimensionality sampling scheme has been recently proposed which requires the optimal number of samples equal to the number of degrees of freedom of the signal in the spectral (harmonic) domain. The computation of the spherical harmonic transform (SHT) associated with the optimal-dimensionality sampling requires the inversion of a series of linear systems in an iterative manner. The stability of the inversion depends on the placement of iso-latitude rings of samples along co-latitude. In this work, we have developed a method to place these iso-latitude rings of samples with the objective of improving the well-conditioning of the linear systems involved in the computation of the SHT. We also propose a multi-pass SHT algorithm to iteratively improve the accuracy of the SHT of band-limited signals. Furthermore, we review the changes in the computational complexity and improvement in accuracy of the SHT with the embedding of the proposed methods. Through numerical experiments, we illustrate that the proposed variations and improvements in the SHT algorithm corresponding to the optimal-dimensionality sampling scheme significantly enhance the accuracy of the SHT.
The ordinary linear differential equations with constant coefficients can be solved by the algebraic methods and the solutions are obtained by elementary functions. In practice, the class of this kind of differential ...
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ISBN:
(纸本)9789810581923
The ordinary linear differential equations with constant coefficients can be solved by the algebraic methods and the solutions are obtained by elementary functions. In practice, the class of this kind of differential equations is rather narrow. The most of the differential equations met in mathematics, physics and engineering sciences remain out of this class. In such cases, it is searched for solutions in form of infinite series. A new theory of functions named as higher transcendant functions or special functions were set up. The Legendre and Bessel equations are of this type. They appear in problems on vibrations, electric field, heat conduction, fluid flow etc. In this paper the authors intend to show by means of four interesting applications from the field of structural and mechanical engineering how still a powerful tool is the method of series solutions, beside the algebraic and numericalmethods;how easy can the problems be handled by this method using the computer softwares prepared especially for mathematics. The results are compared with the numerical solutions.
Basing on recent results on the stability of collocation methods applied to Cauchy singular integral equations with additional fixed singularities we give necessary and sufficient conditions for the stability of collo...
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Basing on recent results on the stability of collocation methods applied to Cauchy singular integral equations with additional fixed singularities we give necessary and sufficient conditions for the stability of collocation-quadrature methods for such equations. These methods have the advantage that the respective system of equations has a very simple structure and allows to apply fast summation methods which results in a fast algorithm with (O(n log n) complexity. We present numerical results of the application of the proposed collocation quadrature methods to the notched half plane problem of two-dimensional elasticity theory. (C) 2015 Elsevier Inc. All rights reserved.
Focusing on special matrices and matrices which are in some sense `near to structured matrices, this volume covers a broad range of topics of current interest in numericallinearalgebra. Exploitation of these less ob...
ISBN:
(纸本)9783319498867
Focusing on special matrices and matrices which are in some sense `near to structured matrices, this volume covers a broad range of topics of current interest in numericallinearalgebra. Exploitation of these less obvious structural properties can be of great importance in the design of efficient numericalmethods, for example algorithms for matrices with low-rank block structure, matrices with decay, and structured tensor computations. applications range from quantum chemistry to queuing theory. Structured matrices arise frequently in applications. Examples include banded and sparse matrices, Toeplitz-type matrices, and matrices with semi-separable or quasi-separable structure, as well as Hamiltonian and symplectic matrices. The associated literature is enormous, and many efficient algorithms have been developed for solving problems involving such matrices. The text arose from a C.I.M.E. course held in Cetraro (Italy) in June 2015 which aimed to present this fast growing field to young researchers, exploiting the expertise of five leading lecturers with different theoretical and application perspectives.
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