Commit 0bdea66b authored by Marco Berzborn's avatar Marco Berzborn
Browse files

Download hyperinterpolation sampling points from Womersleys homepage

Allows for samplings with higher SH orders and improved numeric
precision
parent 443fa6ae
function s = ita_sph_sampling_hyperinterpolation(nmax)
% This function creates a spherical sampling with the property that its
% spherical harmonics function can be inverted.
%
% The set of points is downloaded from Womersleys homepage:
% http://web.maths.unsw.edu.au/~rsw/Sphere/Extremal/New/index.html
%
% The SHT thus writes: f_SH = inv(s.Y) * f;
% and the ISHT: f = s.Y * f_SH;
......@@ -10,18 +13,18 @@ function s = ita_sph_sampling_hyperinterpolation(nmax)
% You can find the license for this m-file in the application folder.
% </ITA-Toolbox>
% can be a natural number 1..29
if nmax > 29
% can be a natural number 1..165
if nmax > 165
error('pre-calculated points only for hyperinterpolation up to order 29');
end
nSH = (nmax+1).^2;
filename = ['/Womersley/md' num2str(nmax,'%02d') '.' num2str(nSH,'%04d')];
filename = ['md' num2str(nmax,'%03d') '.' num2str(nSH,'%05d')];
url = 'http://www.ita-toolbox.org/Griddata';
url = 'http://web.maths.unsw.edu.au/~rsw/Sphere/Extremal/New/';
hyper = str2num(urlread([url filename])); %#ok<ST2NM>
s = itaSamplingSph(hyper(:,1:3),'cart');
s.r = ones(s.nPoints,1);
s.weights = hyper(:,4);
s.nmax = nmax;
s.nmax = nmax;
\ No newline at end of file
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