function [p0,p1]=pleg(x,nelec,nmax);
%PLEG - Used in CPOT, Legendre polynomials
% function [p0,p1]=pleg(x,nelec,nmax);

%<autobegin> ---------------------- 26-May-2004 11:34:08 -----------------------
% --------- Automatically Generated Comments Block Using AUTO_COMMENTS ---------
%
% CATEGORY: Archive
%
% At Check-in: $Author: Mosher $  $Revision: 15 $  $Date: 5/26/04 10:02a $
%
% This software is part of BrainStorm Toolbox Version 2.0 (Alpha) 24-May-2004
% 
% Principal Investigators and Developers:
% ** Richard M. Leahy, PhD, Signal & Image Processing Institute,
%    University of Southern California, Los Angeles, CA
% ** John C. Mosher, PhD, Biophysics Group,
%    Los Alamos National Laboratory, Los Alamos, NM
% ** Sylvain Baillet, PhD, Cognitive Neuroscience & Brain Imaging Laboratory,
%    CNRS, Hopital de la Salpetriere, Paris, France
% 
% See BrainStorm website at http://neuroimage.usc.edu for further information.
% 
% Copyright (c) 2004 BrainStorm by the University of Southern California
% This software distributed  under the terms of the GNU General Public License
% as published by the Free Software Foundation. Further details on the GPL
% license can be found at http://www.gnu.org/copyleft/gpl.html .
% 
% FOR RESEARCH PURPOSES ONLY. THE SOFTWARE IS PROVIDED "AS IS," AND THE
% UNIVERSITY OF SOUTHERN CALIFORNIA AND ITS COLLABORATORS DO NOT MAKE ANY
% WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF
% MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, NOR DO THEY ASSUME ANY
% LIABILITY OR RESPONSIBILITY FOR THE USE OF THIS SOFTWARE.
%<autoend> ------------------------ 26-May-2004 11:34:08 -----------------------

p0(1,:)=x;
p1(1,:)=sqrt(1-x.*x);
p0n=ones(1,nelec);
p1n=zeros(1,nelec);
for n=2:nmax
   pint=(2*(n-1)+1)*x.*p0(n-1,:)-(n-1)*p0n;
   p0n=p0(n-1,:);
   p0(n,:)=pint/n;
   pint=(2*(n-1)+1)*x.*p1(n-1,:)-n*p1n;
   p1n=p1(n-1,:);
   p1(n,:)=pint/(n-1);
end
