Matches 1 - 50 out of 431 1 2 3 4 5 6 7 8 9 >


Match Document Document Title
298966071 Block factorizations and QD-type transformations for the [MR.sup.3] algorithm.  
Factorizing symmetric tridiagonal matrices and propagating the factorizations to shifted matrices are central tasks in the [MR.sup.3] algorithm for computing partial eigensystems. In this paper we...
298966070 Reduced rank extrapolation applied to electronic structure computations.  
This paper presents a new approach for accelerating the convergence of a method for solving a nonlinear eigenvalue problem that arises in electronic structure computations. Specifically, we seek...
298966069 A posteriori error estimation for the Legendre collocation method applied to integral-algebraic Volterra equations.  
In this work, we analyze the Legendre collocation method for a mixed system of Volterra integral equations of the first and second kind which is known as Integral Algebraic Equations (IAEs). In...
298966068 Stieltjes interlacing of zeros of Jacobi polynomials from different sequences.  
A theorem of Stieltjes proves that, given any sequence [{[p.sub.n]}.sup.[infinity].sub.n=0] of orthogonal polynomials, there is at least one zero of [p.sub.n] between any two consecutive zeros...
298966067 Computation of the torsional modes in an axisymmetric elastic layer.  
This paper is devoted to the numerical study of an eigenvalue problem modeling the torsional modes in an infinite and axisymmetric elastic layer. In the cylindrical coordinates (r, z), without...
298966066 Perturbation analysis for complex symmetric, skew symmetric, even and odd matrix polynomials.  
In this work we propose a general framework for the structured perturbation analysis of several classes of structured matrix polynomials in homogeneous form, including complex...
298966065 Application of barycenter refined meshes in linear elasticity and incompressible fluid dynamics.  
The paper demonstrates that enhanced stability properties of some finite element methods on barycenter refined meshes enables efficient numerical treatment of problems involving incompressible or...
298966064 Convergence analysis of minimization-based noise level-free parameter choice rules for linear ill-posed problems.  
Minimization-based noise level-free parameter choice rules for the selection of the regularization parameter in linear ill-posed problems are studied. Abstract convergence results for spectral...
298966063 A linear constructive approximation for integrable functions and a parametric quadrature model based on a generalization of Ostrowski-Gruss type inequalities.  
A new generalization of Ostrowski-Gruss type inequalities, depending on a parameter [lambda], is introduced in order to construct a specific linear approximation for integrable functions. Some...
298966062 Evaluating the frechet derivative of the matrix pth root.  
This paper shows that computing the Frechet derivative of the matrix pth root is equivalent to solve a sequence of p Sylvester equations. This provides the theoretical support to design an...
298966061 Positivity of DLV and MDLVS algorithms for computing singular values.  
The discrete Lotka-Volterra (dLV) and the modified dLV with shift (mdLVs) algorithms for computing bidiagonal matrix singular values are considered. Positivity of the variables of the dLV...
298966060 Pseudospectral mapping theorem II.  
The pseudospectrum has become an important quantity for analyzing stability of non-normal systems. This paper is a continuation of an earlier paper of this author where a mapping theorem for...
298966059 Robust rational interpolation and least-squares.  
An efficient and robust algorithm and a Matlab code ratdisk are presented for rational interpolation or linearized least-squares approximation of a function based on its values at points equally...
298966058 Two efficient SVD/Krylov algorithms for model order reduction of large scale systems.  
We present two efficient algorithms to produce a reduced order model of a time-invariant linear dynamical system by approximate balanced truncation. Attention is focused on the use of the...
298966057 Fields of values and inclusion regions for matrix pencils.  
We are interested in (approximate) eigenvalue inclusion regions for matrix pencils (A, B), in particular of large dimension, based on certain fields of values. We show how the usual field of...
298966056 Steady--state analysis of Google--like stochastic matrices with block iterative methods.  
A Google--like matrix is a positive stochastic matrix given by a convex combination of a sparse, nonnegative matrix and a particular rank one matrix. Google itself uses the steady--state vector of...
298966055 Error estimates for general fidelities.  
Appropriate error estimation for regularization methods in imaging and inverse problems is of enormous importance for controlling approximation properties and understanding types of solutions that...
298966054 Applications of a nonnegatively constrained iterative method with statistically based stopping rules to CT, PET, and SPECT imaging.  
In this paper, we extend a nonnegatively constrained iterative method and three stopping rules for its iteration to the medical imaging inverse problems of computed tomography (CT), positron...
298966053 On an SVD-based algorithm for identifying meta-stable states of Markov chains.  
A Markov chain is a sequence of random variables X = {[x.sub.t]} that take on values in a state space S. A meta-stable state with respect to X is a collection of states E [subset or equal to] S...
298966052 A preconditioner for a FETI-DP method for mortar element discretization of a 4th order problem in 2D.  
In this paper a parallel preconditioner for a FETI-DP formulation for a mortar discretization of a fourth order problem is presented and analyzed. We show that the condition number of the...
298966051 Analysis of a non-standard finite element method based on boundary integral operators.  
We present and analyze a non-standard finite element method based on element-local boundary integral operators that permits polyhedral element shapes as well as meshes with hanging nodes. The...
298966050 A spectral method for the eigenvalue problem for elliptic equations.  
Let [OMEGA] be an open, simply connected, and bounded region in [R.sup.d] d [greater than or equal to] 2, and assume its boundary [delta][OMEGA] is smooth. Consider solving the eigenvalue...
298966049 Coarsening invariance and bucket-sorted independent sets for algebraic multigrid.  
Independent set-based coarse-grid selection algorithms for algebraic multigrid are defined by their policies for weight initialization, independent set selection, and weight update. In this paper,...
298966048 Benchmarking aggregation AMG for linear systems in CFD simulations of compressible internal flows.  
The performance of parallel implementations of three fundamentally different aggregation AMG (algebraic multigrid) solvers, including novel k-cycle methods, for systems of linear equations...
298966047 Mapping directed networks.  
We develop and test a new mapping that can be applied to directed unweighted networks. Although not a "matrix function" in the classical matrix theory sense, this mapping converts an...
298966046 Semi-convergence and relaxation parameters for a class of SIRT algorithms.  
This paper is concerned with the Simultaneous Iterative Reconstruction Technique (SIRT) class of iterative methods for solving inverse problems. Based on a careful analysis of the...
298966045 An analysis of low-rank modifications of preconditioners for saddle point systems.  
We characterize the spectral behavior of a primal Schur-complement-based block diagonal preconditioner for saddle point systems, subject to low-rank modifications. This is motivated by a desire to...
298966044 A robust spectral method for finding lumpings and meta stable states of non-reversible Markov chains.  
A spectral method for identifying lumping in large Markov chains is presented. The identification of meta stable states is treated as a special case. The method is based on the spectral analysis...
298966043 Adaptive reduction-based multigrid for nearly singular and highly disordered physical systems.  
Classical multigrid solution of linear systems with matrices that have highly variable entries and are nearly singular is made difficult by the compounding difficulties introduced by these two...
298966042 A streaming approach for sparse matrix products and its application in Galerkin multigrid methods.  
In this paper, we present a numerical algorithm for computing products of the form R K [R.sup.T].e R, [R.sup.T], and K are sparse matrices. By reformulating the problem into the simultaneous...
298966041 Accumulation of global error in Lie group methods for linear ordinary differential equations.  
In this paper we will investigate how the local errors accumulate to the global error in Lie group methods for linear ODEs. The concept of the local and global errors has to be redefined to fit in...
298966040 Two-level nonlinear elimination based preconditioners for inexact Newton methods with application in shocked duct flow calculation.  
The class of Newton methods is popular for solving large sparse nonlinear algebraic systems of equations arising from the discretization of partial differential equations. The method offers...
298966039 A weakly over-penalized symmetric interior penalty method for the biharmonic problem.  
We study a weakly over-penalized symmetric interior penalty method for the biharmonic problem that is intrinsically parallel. Both a priori error analysis and a posteriori error analysis are...
298966038 On a non-stagnation condition for GMRES and application to saddle point matrices.  
In Simoncini and Szyld [Numer. Math., 109 (2008), pp. 477-487] a new non-stagnation condition for the convergence of GMRES on indefinite problems was proposed. In this paper we derive an enhanced...
298966037 New quadrilateral mixed finite elements.  
In this paper, we introduce a new family of mixed finite element spaces of higher order (k [greater than or equal to] 1) on general quadrilateral grids. A typical element has two fewer degrees of...
298966036 An implicit approximate inverse preconditioner for saddle point problems.  
We present a preconditioner for saddle point problems which is based on an approximation of an implicit representation of the inverse of the saddle point matrix. Whereas this preconditioner does...
298966035 A gradient recovery operator based on an oblique projection.  
We present a construction of a gradient recovery operator based on an oblique projection, where the basis functions of two involved spaces satisfy a condition of biorthogonality. The...
298966034 Computing exp(-[tau]A)b with Laguerre polynomials.  
This paper discusses a method based on Laguerre polynomials combined with a Filtered Conjugate Residual (FCR) framework to compute the product of the exponential of a matrix by a vector. The...
298966033 An aggregation-based algebraic multigrid method.  
An algebraic multigrid method is presented to solve large systems of linear equations. The coarsening is obtained by aggregation of the unknowns. The aggregation scheme uses two passes of a...
298966032 On weighted lacunary interpolation.  
In this paper the regularity of a special lacunary interpolation problem is investigated, where for a given r (r [greater than or equal to] 2, r [member of] N) the derivatives up to the r-2nd...
298966031 On the approximation of analytic functions by the q-Bernstein polynomials in the case q > 1.  
Since for q > 1, the q-Bernstein polynomials [B.sub.n, q] are not positive linear operators on C[0, 1], the investigation of their convergence properties turns out to be much more difficult than...
298966030 Convergence rates for regularization with sparsity constraints.  
Tikhonov regularization with p-powers of the weighted [l.sub.p] norms as penalties, with p [member of] (1, 2), have been employed recently in reconstruction of sparse solutions of ill-posed...
298966029 The Analytic SVD: on the non-generic points on the path.  
A new technique for computing the Analytic SVD is proposed. The idea is to follow a branch ofjust one simple singular value and the corresponding left/right singular vector. Numerical computation...
298966028 Analysis of the finite element method for transmission/mixed boundary value problems on general polygonal domains.  
We study theoretical and practical issues arising in the implementation of the Finite Element Method for a strongly elliptic second order equation with jump discontinuities in its coefficients on...
298966027 Block approximate inverse preconditioners for sparse nonsymmetric linear systems.  
In this paper block approximate inverse preconditioners to solve sparse nonsymmetric linear systems with iterative Krylov subspace methods are studied. The computation of the preconditioners...
298966026 Approximate Fekete points for weighted polynomial interpolation.  
We compute approximate Fekete points for weighted polynomial interpolation by a recent algorithm based on QR factorizations of Vandermonde matrices. We consider in particular the case of...
298751441 Slit maps and Schwarz-Christoffel maps for multiply connected domains.  
We review recent derivations of formulas for conformai maps from finitely connected domains with circular holes to canonical radial or circular slit domains. The formulas are infinite products...
298751440 Condition number analysis for various forms of block matrix preconditioners.  
Various forms of preconditioners for elliptic finite element matrices are studied, based on suitable block matrix partitionings. Bounds for the resulting condition numbers are given, including a...
298751439 Discrete maximum principles for the FEM solution of some nonlinear parabolic problems.  
Discrete maximum principles are established for finite element approximations of nonlinear parabolic problems. The conditions on the space and time discretizations are similar to the usual...
298751438 IDR explained.  
The Induced Dimension Reduction (IDR) method is a Krylov space method for solving linear systems that was developed by Peter Sonneveld around 1979. It was noticed by only a few people, and mainly...

Matches 1 - 50 out of 431 1 2 3 4 5 6 7 8 9 >