Many inequality relations between real vector quantities can be succinctly expressed as “weak (sub)majorization” relations using the symbol ≺w. We explain these ideas and apply them in several areas, angles between subspaces, Ritz values, and graph Laplacian spectra, which we show are all surprisingly related. Let Θ(X ,Y) be the vector of principal angles in nondecreasing order between subspace...

This paper is concerned with solving large-scale eigenvalue problems by algebraic sub-structuring and contour integral. We combine Algebraic Sub-structuring (AS) method and the Contour Integral Rayleigh-Ritz (CIRR) method. The AS method calculates approximate eigenpairs fast and has been shown to be efficient for vibration and acoustic analysis. However, the application areas of this method hav...

The IDR method of Sonneveld and van Gijzen [SIAM J. Sci. Comput., 31:1035–1062, 2008] is shown to be a Petrov-Galerkin (projection) method with a particular choice of left Krylov subspaces; these left subspaces are rational Krylov spaces. Consequently, other methods, such as BiCGStab and ML(s)BiCGStab, which are mathematically equivalent to some versions of IDR, can also be interpreted as Petro...

The radiation impedance is an essential parameter in analyzing the vibroacoustic response of planar source. In order to calculate acoustic rectangular plate with arbitrary boundary conditions, a unified approximate approach proposed this study. displacement function expressed form supplemented two-dimensional Fourier cosine series, which can be solved by Rayleigh–Ritz method. radiated field fro...

The harmonic block Arnoldi method can be used to find interior eigenpairs of large matrices. Given a target point or shift to which the needed interior eigenvalues are close, the desired interior eigenpairs are the eigenvalues nearest and the associated eigenvectors. However, it has been shown that the harmonic Ritz vectors may converge erratically and even may fail to do so. To do a better job...

In this research, we analyze the acoustic–vibration coupling of liquid-filled cylindrical shells under complex excitations. A calculation model to determine acoustic characteristics and steady-state response a shell coupled an cavity is proposed. The displacement sound pressure are described by Chebyshev–Fourier series in three dimensions. uncertain expansion coefficient determined with Rayleig...

Abstract: This paper presents an accurate numerical method for solving a class of fractional optimal control problems (FOCPs). The fractional derivative in these problems is in the Caputo sense. In this technique, we approximate FOCPs and end up with a finite dimensional problem. The method is based on the combination of the useful properties of Chebyshev polynomials approximation and finite di...