% SPHERROR - CHANCENTER sub function to compute minimum distance
%               of Cartesian coordinates to a sphere
%
% Author: Scott Makeig, CNL / Salk Institute, 2000

% Copyright (C) Scott Makeig, CNL / Salk Institute, 2000
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% This file is part of EEGLAB, see http://www.eeglab.org
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function wobble = spherror(center,x,y,z)
  
% 03/14/02 corrected wobble calculation -lf
  
x = x - center(1);  % center the points at (0,0,0)
y = y - center(2);
z = z - center(3);
radius = (sqrt(x.^2+y.^2+z.^2)); % distances from the center
wobble = std(radius-mean(radius)); % test if xyz values are on a sphere