subcorr_gui

(Toolbox/subcorr_gui.m in BrainStorm 2.0 (Alpha))

Function Synopsis

[Co,X,Y] = subcorr_gui(A,B,GUI);

Help Text

SUBCORR_GUI - Subcorr function custom to the gui features
 function [Co,X,Y] = subcorr_gui(A,B,GUI);
 GUI.REG is a regularization switch
 GUI is a struction with regularization fields to match
 See REGCHECK
 Note that BOTH A and B are regularized in this call.

 approaches Truncated Condition and Truncated Energy have
  effectively the regularization built in by simply truncating the space.
  Column normalization should
  have already been done before the call, if requested.
  Here we are only concerned with Tikhonov regularization by building the
  filter functions, if requested.

Cross-Reference Information

regsubspace                        C:\BrainStorm_2001\Toolbox\regsubspace.m

rapmusic_gui                       C:\BrainStorm_2001\Toolbox\rapmusic_gui.m
source_grids                       C:\BrainStorm_2001\Toolbox\source_grids.m

Listing of function C:\BrainStorm_2001\Toolbox\subcorr_gui.m

function [Co,X,Y] = subcorr_gui(A,B,GUI);
%SUBCORR_GUI - Subcorr function custom to the gui features
% function [Co,X,Y] = subcorr_gui(A,B,GUI);
% GUI.REG is a regularization switch
% GUI is a struction with regularization fields to match
% See REGCHECK
% Note that BOTH A and B are regularized in this call.
%
% approaches Truncated Condition and Truncated Energy have
%  effectively the regularization built in by simply truncating the space.
%  Column normalization should
%  have already been done before the call, if requested.
%  Here we are only concerned with Tikhonov regularization by building the
%  filter functions, if requested.

%<autobegin> ---------------------- 26-May-2004 11:34:33 -----------------------
% --------- Automatically Generated Comments Block Using AUTO_COMMENTS ---------
%
% CATEGORY: Inverse Modeling
%
% Alphabetical list of external functions (non-Matlab):
%   toolbox\regsubspace.m
%   toolbox\subcorr_gui.m  NOTE: Routine calls itself explicitly
%
% At Check-in: $Author: Mosher $  $Revision: 13 $  $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 11:34:33 -----------------------

% ----------------------------- Script History ---------------------------------
% 1994 by John C. Mosher, Ph.D.
% 10/29/99 JCM, some optimizations.
% JCM 10-May-2002 Adjustments to display in command window, not message window
% 19-May-2004 JCM Comments Cleaning
% ----------------------------- Script History ---------------------------------


[Ua,Sa,Va]= svd(A,0);
[Ub,Sb,Vb]= svd(B,0);

% trim the subspace to the appropriate size
Ua = regsubspace(GUI,Ua,Sa);
Ub = regsubspace(GUI,Ub,Sb);

C = Ua'*Ub;

if(nargout < 2)  % want only angles
   
   Co = svd(C);
   too_big = find(Co > 1);    % numerical error
   Co(too_big) = 1; % matlab 5.3 allows scalar to vector mapping
   too_small = find(Co < 0); % more numerical error
   Co(too_small) = 0; % the null case is also adequately handled
   return
   
else % nargout is 2 or more
   
   % trim to the rank
   rnk_a = size(Ua,2);
   rnk_b = size(Ub,2);

   if(length(Sa) > 1),
      Sa = diag(Sa);
   end
   if(length(Sb) > 1),
      Sb = diag(Sb);
   end
   
   Sa = Sa(1:rnk_a);
   Va = Va(:,1:rnk_a);
   
   Sb = Sb(1:rnk_b);
   Vb = Vb(:,1:rnk_b);
      
   [Uc,Co,Vc] = svd(C);
   if(min(size(Co))==1),
      Co = Co(1);
   else,
      Co = diag(Co);
   end
   too_big = find(Co > 1);    % numerical error
   Co(too_big) = ones(length(too_big),1);
   too_small = find(Co < 0);    % numerical error
   Co(too_small) = zeros(length(too_small),1);
   
   switch GUI.REG
   case 'Tikhonov'
      Lambda = Sa(1)/GUI.Tikhonov; % relative condition setting
      Fa = Sa.^2 ./ (Sa.^2 + Lambda^2);
      Lambda = Sb(1)/GUI.Tikhonov; % relative condition setting
      Fb = Sb.^2 ./ (Sb.^2 + Lambda^2);
      VaSai = Va*diag(Fa./Sa); % filtered
      VbSbi = Vb*diag(Fb./Sb);
   otherwise
      % all other conditions are truncated types
      VaSai = Va*diag(1../Sa);
      VbSbi = Vb*diag(1../Sb);
   end
   
   X = VaSai*Uc;
   Y = VbSbi*Vc;
   
   % debugging comments
   switch GUI.REG
   case 'Tikhonov'
      
      % don't send to the message window,
      %  too detailed, more of a debugging set
      disp('Subcorr gui Comments:')
      disp(['Co:          ',sprintf('%.4f ',Co)]);
      disp(['Regularized: ',sprintf('%.4f ',subcorr_gui(A*X(:,1),B*Y(:,1),struct('REG','None')))])
      disp(['Filters a and b: ',sprintf('%.3f ',Fa) ' ; ' sprintf('%.3f ',Fb)])
      
   otherwise
      % nothing, orientation not altered
   end
   
   return
   
end

return