Combined preorder and postorder traversal algorithm for the analysis of singular systems by Haar wavelets.
Complexity of an algorithm for solving saddle-point systems with singular blocks arising in wavelet-Galerkin discretizations
The paper deals with fast solving of large saddle-point systems arising in wavelet-Galerkin discretizations of separable elliptic PDEs. The periodized orthonormal compactly supported wavelets of the tensor product type together with the fictitious domain method are used. A special structure of matrices makes it possible to utilize the fast Fourier transform that determines the complexity of the algorithm. Numerical experiments confirm theoretical results.
Computation of the fundamental solution of electrodynamics for anisotropic materials
A new method for computation of the fundamental solution of electrodynamics for general anisotropic nondispersive materials is suggested. It consists of several steps: equations for each column of the fundamental matrix are reduced to a symmetric hyperbolic system; using the Fourier transform with respect to space variables and matrix transformations, formulae for Fourier images of the fundamental matrix columns are obtained; finally, the fundamental solution is computed by the inverse Fourier transform....
Computing discrete convolutions with verified accuracy via Banach algebras and the FFT
We introduce a method to compute rigorous component-wise enclosures of discrete convolutions using the fast Fourier transform, the properties of Banach algebras, and interval arithmetic. The purpose of this new approach is to improve the implementation and the applicability of computer-assisted proofs performed in weighed Banach algebras of Fourier/Chebyshev sequences, whose norms are known to be numerically unstable. We introduce some application examples, in particular a rigorous aposteriori...
Construction of interval wavelet based on restricted variational principle and its application for solving differential equations.
Convergence analysis of a Fourier-based solution method of the Laplace equation for a model of magnetic recording.
Convolutive decomposition and fast summation methods for discrete-velocity approximations of the Boltzmann equation
Discrete-velocity approximations represent a popular way for computing the Boltzmann collision operator. The direct numerical evaluation of such methods involve a prohibitive cost, typically O(N2d + 1) where d is the dimension of the velocity space. In this paper, following the ideas introduced in [C. Mouhot and L. Pareschi, C. R. Acad. Sci. Paris Sér. I Math. 339 (2004) 71–76, C. Mouhot and L. Pareschi, Math. Comput. 75 (2006) 1833–1852], we derive fast summation techniques for the evaluation of...
Curriculum vita of Prof. Vasil Atanasov Popov
Our primary goal in this preamble is to highlight the best of Vasil Popov’s mathematical achievements and ideas. V. Popov showed his extraordinary talent for mathematics in his early papers in the (typically Bulgarian) area of approximation in the Hausdorff metric. His results in this area are very well presented in the monograph of his advisor Bl. Sendov, “Hausdorff Approximation”.
Daubechies wavelets on intervals with application to BVPs
In this paper, Daubechies wavelets on intervals are investigated. An analytic technique for evaluating various types of integrals containing the scaling functions is proposed; they are compared with classical techniques. Finally, these results are applied to two-point boundary value problems.
Designing Local Orthogonal Bases on Finite Groups I: Abelian Case.
Designing Local Orthogonal Bases on Finite Groups II: Nonabelian Case.
Determination of the number of texture segments using wavelets.
Determining the weights of a Fourier series neural network on the basis of the multidimensional discrete Fourier transform
This paper presents a method for training a Fourier series neural network on the basis of the multidimensional discrete Fourier transform. The proposed method is characterized by low computational complexity. The article shows how the method can be used for modelling dynamic systems.
Discrete wavelet transforms accelerated sparse preconditioners for dense boundary element systems.
Double Coset Decompositions and Computational Harmonic Analysis on Groups.
Efficient Computation of Fourier Transforms on Compact Groups.
Embedding and a priori wavelet-adaptivity for Dirichlet problems
Embedding and a priori wavelet-adaptivity for Dirichlet problems
The accuracy of the domain embedding method from [A. Rieder, Modél. Math. Anal. Numér.32 (1998) 405-431] for the solution of Dirichlet problems suffers under a coarse boundary approximation. To overcome this drawback the method is furnished with an a priori (static) strategy for an adaptive approximation space refinement near the boundary. This is done by selecting suitable wavelet subspaces. Error estimates and numerical experiments validate the proposed adaptive scheme. In contrast to similar,...
Encryption schemes using finite frames and Hadamard arrays.
Error bound of certain Gaussian quadrature rules for trigonometric polynomials