A new method for creating sparse design velocity fields

2006

We present a novel method for the computation of mesh node sensitivities with respect to the boundary node movement. The sensitivity field is sparse in a sense that movement of each boundary node affects only given amount of inner mesh nodes, which can result in considerable savings in the storage space. The method needs minimal control from the user, and it does not place any restrictions (such as block structure) on the mesh. Use of the method is demonstrated with a shape optimization problem using CAD-free parametrization. A solution to the classical die-swell free boundary problem by coupling the boundary node locations with the state variables is also presented. In that case, sparsity …

Proceedings of the 23rd Paediatric Rheumatology European Society Congress: part one

2017

Body size at birth and coronary heart disease-related hospital care in adult men : Findings from the Helsinki Birth Cohort Study

2017

Aim: We investigated, among those who had been hospitalized at least once due to coronary heart disease (CHD), the relationship between ponderal index (PI, birthweight/length3) at birth, a measure of thinness, and the age at first hospitalization due to CHD, the number of CHD-related hospital care episodes, and cost of CHD-related hospital care from young adulthood to old age. Methods and results: Data from the Helsinki Birth Cohort Study included 964 men born in Helsinki, Finland during 1934–1944, who had been hospitalized due to CHD and had birth anthropometrics data. PI (kg/m3) was categorized into low (27.5). CHD-related hospital care data were available from 1971 to 2013. We observed a…

Fast Direct Solver for a Time-harmonic Electromagnetic Problem with an Application

2003

A fast direct solution of a periodic problem derived from the time-harmonic Maxwell’s equations is considered. The problem is discretized by low order hexahedral finite elements proposed by Nedelec. The solver is based on the application of FFT, and it has the computational cost O(N log N). An application to scattering of an electromagnetic wave by a periodic structure is presented.

Numerical Study of Two Sparse AMG-methods

2003

A sparse algebraic multigrid method is studied as a cheap and accurate way to compute approximations of Schur complements of matrices arising from the discretization of some symmetric and positive definite partial differential operators. The construction of such a multigrid is discussed and numerical experiments are used to verify the properties of the method.

Computation of a few smallest eigenvalues of elliptic operators using fast elliptic solvers

2001

The computation of a few smallest eigenvalues of generalized algebraic eigenvalue problems is studied. The considered problems are obtained by discretizing self-adjoint second-order elliptic partial differential eigenvalue problems in two- or three-dimensional domains. The standard Lanczos algorithm with the complete orthogonalization is used to compute some eigenvalues of the inverted eigenvalue problem. Under suitable assumptions, the number of Lanczos iterations is shown to be independent of the problem size. The arising linear problems are solved using some standard fast elliptic solver. Numerical experiments demonstrate that the inverted problem is much easier to solve with the Lanczos…