IMA Journal of Numerical Analysis Advance Access originally published online on October 3, 2008
IMA Journal of Numerical Analysis 2009 29(4):960-985; doi:10.1093/imanum/drn047
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Convolution of hp-functions on locally refined grids

Max-Planck-Institut für Mathematik in den Naturwissenschaften, Inselstrasse 22–26, D-04103 Leipzig, Germany
Email: wh{at}mis.mpg.de
Received on 31 May 2007. Revised on 18 June 2008.
| Abstract |
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Usually, the fast evaluation of a convolution integral
requires that the functions f and g have a simple structure based on an equidistant grid in order to apply the fast Fourier transform. Here, we discuss the efficient performance of the convolution of hp-functions in certain locally refined grids. More precisely, the convolution result is projected into some given hp-space (Galerkin approximation). The overall cost is O(p2N log N), where N is the sum of the dimensions of the subspaces containing f, g and the resulting function, while p is the maximal polynomial degree.
Key Words: convolution integral; hp-finite elements; nonuniform grids; local refinement