colnorm

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

Function Synopsis

[nrm,Anrm] = colnorm(A);

Help Text

COLNORM - Calculate L2 norm for each column of a matrix and normalize
 function [nrm,Anrm] = colnorm(A);
 calculate the Euclidean norm of each COLUMN in A, return as
 a row vector with same number of cols as A.
 Optionally, return A with each column now normalized

Cross-Reference Information

bst_headmodeler                    C:\BrainStorm_2001\Toolbox\bst_headmodeler.m
bst_sourceimaging                  C:\BrainStorm_2001\Toolbox\bst_sourceimaging.m
curvature_cortex                   C:\BrainStorm_2001\Toolbox\curvature_cortex.m
headmodeler_gui                    C:\BrainStorm_2001\Toolbox\headmodeler_gui.m
lcmvbf                             C:\BrainStorm_2001\Toolbox\lcmvbf.m
least_squares_fit                  C:\BrainStorm_2001\Toolbox\least_squares_fit.m
minnorm                            C:\BrainStorm_2001\Toolbox\minnorm.m
mritool_cb                         C:\BrainStorm_2001\Toolbox\mritool_cb.m
os_meg                             C:\BrainStorm_2001\Toolbox\os_meg.m
overlapping_sphere                 C:\BrainStorm_2001\Toolbox\overlapping_sphere.m
overlapping_sphere_fmins           C:\BrainStorm_2001\Toolbox\overlapping_sphere_fmins.m
rapmusic_gui                       C:\BrainStorm_2001\Toolbox\rapmusic_gui.m
ray_intersect                      C:\BrainStorm_2001\Toolbox\ray_intersect.m
results_time_series                C:\BrainStorm_2001\Toolbox\results_time_series.m
source_grids                       C:\BrainStorm_2001\Toolbox\source_grids.m
tesselate                          C:\BrainStorm_2001\Toolbox\tesselate.m

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

function [nrm,Anrm] = colnorm(A);
%COLNORM - Calculate L2 norm for each column of a matrix and normalize
% function [nrm,Anrm] = colnorm(A);
% calculate the Euclidean norm of each COLUMN in A, return as
% a row vector with same number of cols as A.
% Optionally, return A with each column now normalized

%<autobegin> ---------------------- 26-May-2004 11:29:53 -----------------------
% --------- Automatically Generated Comments Block Using AUTO_COMMENTS ---------
%
% CATEGORY: Utility - Numeric
%
% At Check-in: $Author: Mosher $  $Revision: 14 $  $Date: 5/26/04 9:59a $
%
% 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 11:29:53 -----------------------

% ----------------------------- Script History ---------------------------------
% 1994 by John C. Mosher
% May 6, 1994 JCM author 
% Nov 19, 1996 added Anrm option
% June 13, 1999 JCM optimized the nrm division into A
% 19-May-2004 JCM Comments Cleaning
% ----------------------------- Script History ---------------------------------

[m,n] = size(A);

if(m>1),            % multiple rows
  nrm = sqrt(sum([A.*conj(A)]));
else                % A is row vector
  nrm = abs(A);            % just return mag of each column
end

if(nargout > 1),
  ndx = find(nrm>0);        % any zero norm?
  Anrm = zeros(size(A));
  % normalize any non-zero columns
  Anrm(:,ndx) = A(:,ndx) ./ nrm(ones(m,1),ndx);
end

return