posact

 posact() - Make runica() activations all RMS-positive.
            Adjust weights and inverse weight matrix accordingly.

 Usage: >> [actout,winvout,weightsout] = posact(data,weights,sphere) 

 Inputs:
    data        = runica() input data
    weights     = runica() weights
    sphere      = runica() sphere {default|0 -> eye()}

 Outputs:
    actout      = activations reoriented to be RMS-positive
    winvout     = inv(weights*sphere) reoriented to match actout
    weightsout  = weights reoriented to match actout (sphere unchanged)

 Author: Scott Makeig, SCCN/INC/UCSD, La Jolla, 11/97

0001 % posact() - Make runica() activations all RMS-positive.
0002 %            Adjust weights and inverse weight matrix accordingly.
0003 %
0004 % Usage: >> [actout,winvout,weightsout] = posact(data,weights,sphere)
0005 %
0006 % Inputs:
0007 %    data        = runica() input data
0008 %    weights     = runica() weights
0009 %    sphere      = runica() sphere {default|0 -> eye()}
0010 %
0011 % Outputs:
0012 %    actout      = activations reoriented to be RMS-positive
0013 %    winvout     = inv(weights*sphere) reoriented to match actout
0014 %    weightsout  = weights reoriented to match actout (sphere unchanged)
0015 %
0016 % Author: Scott Makeig, SCCN/INC/UCSD, La Jolla, 11/97
0017 
0018 % Copyright (C) 11/97 Scott Makeig, SCCN/INC/UCSD, scott@sccn.ucsd.edu
0019 %
0020 % This program is free software; you can redistribute it and/or modify
0021 % it under the terms of the GNU General Public License as published by
0022 % the Free Software Foundation; either version 2 of the License, or
0023 % (at your option) any later version.
0024 %
0025 % This program is distributed in the hope that it will be useful,
0026 % but WITHOUT ANY WARRANTY; without even the implied warranty of
0027 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0028 % GNU General Public License for more details.
0029 %
0030 % You should have received a copy of the GNU General Public License
0031 % along with this program; if not, write to the Free Software
0032 % Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
0033 
0034 % $Log: posact.m,v $
0035 % Revision 1.1  2002/04/05 17:36:45  jorn
0036 % Initial revision
0037 %
0038 
0039 % 01-25-02 reformated help & license, added links -ad
0040 
0041 function [actout,winvout,weightsout] = posact(data,weights,sphere)
0042 
0043 if nargin < 2
0044    help posact
0045    return
0046 end
0047 if nargin < 3
0048    sphere = 0;
0049 end
0050 
0051 [chans,frames]=size(data);
0052 [r,c]=size(weights);
0053 if sphere == 0
0054   sphere = eye(chans);
0055 end
0056 [sr,sc] = size(sphere);
0057 if sc~= chans
0058    fprintf('posact(): Sizes of sphere and data do not agree.\n')
0059    return
0060 elseif c~=sr
0061    fprintf('posact(): Sizes of weights and sphere do not agree.\n')
0062    return
0063 end
0064 
0065 activations = weights*sphere*data;
0066 
0067 if r==c
0068   winv = inv(weights*sphere);
0069 else
0070   winv = pinv(weights*sphere);
0071 end
0072 
0073 [rows,cols] = size(activations);
0074 
0075 actout = activations;
0076 winvout = winv;
0077 
0078 fprintf('Inverting negative activations: ');
0079 for r=1:rows,
0080         pos = find(activations(r,:)>=0);
0081         posrms = sqrt(sum(activations(r,pos).*activations(r,pos))/length(pos));
0082         neg = find(activations(r,:)<0);
0083         negrms = sqrt(sum(activations(r,neg).*activations(r,neg))/length(neg));
0084         if negrms>posrms
0085             fprintf('-');   
0086             actout(r,:) = -1*activations(r,:);
0087             winvout(:,r) = -1*winv(:,r);
0088         end
0089         fprintf('%d ',r);
0090 end
0091 fprintf('\n');
0092 
0093 if nargout>2
0094   if r==c,
0095     weightsout = inv(winvout);
0096   else
0097     weightsout = pinv(winvout);
0098   end
0099   if nargin>2 % if sphere submitted
0100     weightsout = weightsout*inv(sphere); % separate out the sphering
0101   end
0102 end