Data-Sparse Approximation to Operator-Valued Functions of Elliptic Operator
نویسندگان
چکیده
In previous papers the arithmetic of hierarchical matrices has been described, which allows to compute the inverse, for instance, of finite element stiffness matrices discretising an elliptic operator L. The required computing time is up to logarithmic factors linear in the dimension of the matrix. In particular, this technique can be used for the computation of the discrete analogue of a resolvent (zI − L)−1 , z ∈ C. In the present paper, we consider various operator functions, the operator exponential e−tL, negative fractional powers L−α, the cosine operator function cos(t√L)L−k and, finally, the solution operator of the Lyapunov equation. Using the Dunford-Cauchy representation, we get integrals which can be discretised by a quadrature formula which involves the resolvents (zkI −L)−1 mentioned above. We give error estimates which are partly exponentially, partly polynomially decreasing. AMS Subject Classification: 47A56, 65F30, 15A24, 15A99
منابع مشابه
Data-Sparse Approximation of a Class of Operator-Valued Functions
In the papers [4]-[7] a method for the data-sparse approximation of the solution operators for elliptic, parabolic and hyperbolic PDEs has been developed based on the Dunford-Cauchy representation to the operator-valued functions of interest combined with the hierarchical matrix approximation of the operator resolvents. In the present paper, we discuss how these techniques can be applied to app...
متن کاملData-sparse approximation to a class of operator-valued functions
In earlier papers we developed a method for the data-sparse approximation of the solution operators for elliptic, parabolic, and hyperbolic PDEs based on the Dunford-Cauchy representation to the operator-valued functions of interest combined with the hierarchical matrix approximation of the operator resolvents. In the present paper, we discuss how these techniques can be applied to approximate ...
متن کاملData-sparse approximation to the operator-valued functions of elliptic operator
In previous papers the arithmetic of hierarchical matrices has been described, which allows us to compute the inverse, for instance, of finite element stiffness matrices discretising an elliptic operator L. The required computing time is up to logarithmic factors linear in the dimension of the matrix. In particular, this technique can be used for the computation of the discrete analogue of a re...
متن کاملH - Matrix Approximation for Elliptic Solution Operators inCylindric
We develop a data-sparse and accurate approximation of the normalised hyperbolic operator sine family generated by a strongly P-positive elliptic operator deened in 4, 7]. In the preceding papers 14]-18], a class of H-matrices has been analysed which are data-sparse and allow an approximate matrix arithmetic with almost linear complexity. An H-matrix approximation to the operator exponent with ...
متن کاملQuasicompact and Riesz unital endomorphisms of real Lipschitz algebras of complex-valued functions
We first show that a bounded linear operator $ T $ on a real Banach space $ E $ is quasicompact (Riesz, respectively) if and only if $T': E_{mathbb{C}}longrightarrow E_{mathbb{C}}$ is quasicompact (Riesz, respectively), where the complex Banach space $E_{mathbb{C}}$ is a suitable complexification of $E$ and $T'$ is the complex linear operator on $E_{mathbb{C}}$ associated with $T$. Next, we pr...
متن کامل