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Radial Functions on Compact Support
(1995)SAM Research ReportIn this paper, radial basis functions that are compactly supported and give rise to positive definite interpolation matrices for scattered data are discussed. They are related to the well-known thin plate spline radial functions which are highly useful in applications for gridfree approximation methods. Also, encouraging approximation results for the compactly supported radial functions are shown.Report -
On a Recovery Problem
(1995)SAM Research ReportThis paper concerns itself with the recovery of the coefficients, shifts and, where applicable, dilates of a given form f(\bfx)=∑j=1mcjG(\bfx−\bftj), or f(\bfx)=∑j=1mcjg(\bfaj⋅\bfx−bj),\bfx∈\RRn, where emf/em, emG/em and emg/em are known. That is, we provide a method that identifies the quantities $c_j$, $\bft_j$, $\bfa_j$ and $b_j$. In some cases we can even find emG/em given only emf/em and knowing that emf/em is of the above form.Report -
Fully Discrete Multiscale Galerkin BEM
(1995)SAM Research ReportWe analyze multiscale Galerkin methods for strongly elliptic boundary integral equations of order zero on closed surfaces in $R^3$. Piecewise polynomial, discontinuous multiwavelet bases of any polynomial degree are constructed explicitly. We show that optimal convergence rates in the boundary energy norm and in certain negative norms can be achieved with "compressed" stiffness matrices containing $O(N({\log N})^2)$ nonvanishing entries ...Report -
Eliminating the shortcomings of free datatype definitions
(1995)Technischer Bericht / Eidgenössische Technische Hochschule, Departement InformatikReport -
The Method of Transport for solving the Euler-equations
(1995)SAM Research ReportIn many technical applications it is necessary to compute a numerical solution of complex flow problems in several space dimensions. Most available codes split the multi-dimensional problem into several one-dimension\-al ones. Those are aligned with the cell interfaces of the underlying grid. In some of the applications, e.g.high Mach number flow, this approach does not work very well, since the physical properties of the model equations ...Report