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Slepi/Code/Utilities/spm12/external/mne/mne_pick_channels_cov.m
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mne_pick_channels_cov.m
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function [cov] = mne_pick_channels_cov(orig,include,exclude)
%
% [cov] = mne_pick_channels_cov(orig,include,exclude)
%
% Pick desired channels from a covariance matrix
%
% orig - The original covariance matrix
% include - Channels to include (if empty, include all available)
% exclude - Channels to exclude (if empty, do not exclude any)
%
%
%
%
% Author : Matti Hamalainen, MGH Martinos Center
% License : BSD 3-clause
%
% Revision 1.9 2006/11/21 12:53:49 msh
% Fixed error in picking
%
% Revision 1.8 2006/06/29 22:12:28 msh
% Fixed errors in channel picking
%
% Revision 1.7 2006/05/03 18:53:05 msh
% Approaching Matlab 6.5 backward compatibility
%
% Revision 1.6 2006/04/23 15:29:40 msh
% Added MGH to the copyright
%
% Revision 1.5 2006/04/18 20:44:46 msh
% Added reading of forward solution.
% Use length instead of size when appropriate
%
% Revision 1.4 2006/04/15 12:21:00 msh
% Several small improvements
%
% Revision 1.3 2006/04/14 15:49:49 msh
% Improved the channel selection code and added ch_names to measurement info.
%
% Revision 1.2 2006/04/14 00:45:42 msh
% Added channel picking and fiff_invert_transform
%
% Revision 1.1 2006/04/13 17:05:45 msh
% Added reading of bad channels to fiff_read_meas_info.m
% Added mne_pick_channels_cov.m
%
%
me='MNE:mne_pick_channels_cov';
if nargin == 1
cov = orig;
if isempty(cov.eig) || isempty(cov.eigvec)
decompose_eigen;
end
return;
elseif nargin == 2
exclude = [];
elseif nargin ~= 3
error(me,'Incorrect number of arguments');
end
if isempty(include) && isempty(exclude)
cov = orig;
if isempty(cov.eig) || isempty(cov.eigvec)
decompose_eigen;
end
return;
end
if isempty(orig.names)
error(me,'Cannot pick from a covariance matrix without channel names');
end
cov = orig;
%
% First do the channels to be included
%
sel = fiff_pick_channels(cov.names,include,exclude);
if isempty(sel)
error(me,'Nothing remains after picking');
end
%
% Select the desired stuff
%
if cov.diag
cov.data = cov.data(sel);
else
cov.data = cov.data(:,sel);
cov.data = cov.data(sel,:);
end
for p = 1:size(sel,2)
names{p} = cov.names{sel(p)};
end
cov.names = names;
cov.dim = length(cov.names);
%
% Eigenvalues and vectors are no longer valid
%
decompose_eigen;
%
return;
function decompose_eigen
if cov.diag
cov.eig = cov.data;
cov.eigvec = eye(cov.dim);
else
[ cov.eigvec, cov.eig ] = eig(cov.data);
%
% We use the convention that rows of eigvec are the
% eigenvectors
%
cov.eigvec = cov.eigvec';
cov.eig = diag(cov.eig);
end
end
end
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