Remarques sur les algorithmes de décomposition de domaines
Remembering Alessandro Ossicini
Reorthoganization in the block Lanczos algorithm
Répartition optimale de la puissance dans une centrale hydraulique à réserve pompée
Repeated Modifications of Limit k-Periodic continued Fractions.
Replicant compression coding in Besov spaces
We present here a new proof of the theorem of Birman and Solomyak on the metric entropy of the unit ball of a Besov space on a regular domain of The result is: if s - d(1/π - 1/p)+> 0, then the Kolmogorov metric entropy satisfies H(ε) ~ ε-d/s. This proof takes advantage of the representation of such spaces on wavelet type bases and extends the result to more general spaces. The lower bound is a consequence of very simple probabilistic exponential inequalities. To prove the upper bound,...
Replicant compression coding in Besov spaces
We present here a new proof of the theorem of Birman and Solomyak on the metric entropy of the unit ball of a Besov space on a regular domain of The result is: if then the Kolmogorov metric entropy satisfies . This...
Representación finita de sistemas de infinitas inecuaciones.
Dado un Problema de Programación Semi-Infinita, si se puede obtener una representación finita del conjunto factible, pueden aplicarse para resolver el problema los métodos de programación con restricciones finitas.En la primera parte se caracterizan los sistemas lineales infinitos que pueden ser reducidos a un sistema finito equivalente, dándose además condiciones suficientes y métodos para efectuar tal reducción. En la segunda parte se establecen diferentes procedimientos de obtención de la representación...
Représentation de matrices euclidiennes en vue de leur génération aléatoire
Reproducing kernel methods for solving linear initial-boundary-value problems.
Reproducing kernel particle method and its modification
Meshless methods have become an effective tool for solving problems from engineering practice in last years. They have been successfully applied to problems in solid and fluid mechanics. One of their advantages is that they do not require any explicit mesh in computation. This is the reason why they are useful in the case of large deformations, crack propagations and so on. Reproducing kernel particle method (RKPM) is one of meshless methods. In this contribution we deal with some modifications...
Řešení algebraických a transcendentních rovnic na analogovém počítači
Řešení soustav lineárních algebraických rovnic s komplexními koeficienty
Residual a posteriori error estimators for contact problems in elasticity
This paper is concerned with the unilateral contact problem in linear elasticity. We define two a posteriori error estimators of residual type to evaluate the accuracy of the mixed finite element approximation of the contact problem. Upper and lower bounds of the discretization error are proved for both estimators and several computations are performed to illustrate the theoretical results.
Residual and hierarchical a posteriori error estimates for nonconforming mixed finite element methods
We analyze residual and hierarchical a posteriori error estimates for nonconforming finite element approximations of elliptic problems with variable coefficients. We consider a finite volume box scheme equivalent to a nonconforming mixed finite element method in a Petrov–Galerkin setting. We prove that all the estimators yield global upper and local lower bounds for the discretization error. Finally, we present results illustrating the efficiency of the estimators, for instance, in the simulation...
Residual and hierarchical a posteriori error estimates for nonconforming mixed finite element methods
We analyze residual and hierarchical a posteriori error estimates for nonconforming finite element approximations of elliptic problems with variable coefficients. We consider a finite volume box scheme equivalent to a nonconforming mixed finite element method in a Petrov–Galerkin setting. We prove that all the estimators yield global upper and local lower bounds for the discretization error. Finally, we present results illustrating the efficiency of the estimators, for instance, in the simulation...
Residual based a posteriori error estimators for eddy current computation
Residual based a posteriori error estimators for eddy current computation
We consider H(curl;Ω)-elliptic problems that have been discretized by means of Nédélec's edge elements on tetrahedral meshes. Such problems occur in the numerical computation of eddy currents. From the defect equation we derive localized expressions that can be used as a posteriori error estimators to control adaptive refinement. Under certain assumptions on material parameters and computational domains, we derive local lower bounds and a global upper bound for the total error measured in...
Residual norm behavior for Hybrid LSQR regularization
Hybrid LSQR represents a powerful method for regularization of large-scale discrete inverse problems, where ill-conditioning of the model matrix and ill-posedness of the problem make the solutions seriously sensitive to the unknown noise in the data. Hybrid LSQR combines the iterative Golub-Kahan bidiagonalization with the Tikhonov regularization of the projected problem. While the behavior of the residual norm for the pure LSQR is well understood and can be used to construct a stopping criterion,...
Resilient asynchronous primal Schur method
This paper introduces the application of asynchronous iterations theory within the framework of the primal Schur domain decomposition method. A suitable relaxation scheme is designed, whose asynchronous convergence is established under classical spectral radius conditions. For the usual case where local Schur complement matrices are not constructed, suitable splittings based only on explicitly generated matrices are provided. Numerical experiments are conducted on a supercomputer for both Poisson's...