function[]=imagecf(X,col,nfac)
% draws images of genes in x ordered by elements of A(:,1), or more 
%  than one eigenvector
%  for clarity, this version simply restricts to at most 4 images/evecs -- 
%  easy to modify if required; or use multiple times
%  produces SVD in original order as output
% 
if nargin < 2 
   error('Requires at least two input arguments.'); 
else if nargin==2
	nfac=1;
     else if length(nfac)>4
	     nfac=nfac(1:4); 	
	  end
     end
end

% mean zero the X data prior to SVD
	[m,k]=size(X); 
	[A,D,F]=svd_mw(X-repmat(mean(X,2),1,k));

% how many images? 
nr=1; nc=1; nf=length(nfac);
if (nf==2), nc=2; end; if (nf>2), nr=2; nc=2; end;
clf
for j=1:nf
        subplot(nr,nc,j);
 	[b,i]=sort(A(:,nfac(j))); i=flipud(i);  
        imagesc(X(i,:)); eval(['cmap ',col])
        ylabel(['Genes listed by factor ',int2str(nfac(j))]); 
	xlabel('Samples'); 
end