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

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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