function y=mult_gamma5(x);
% multiplies a vector by gamma5
x=x(:);
ndim=max(size(x));
y=reshape(x,ndim/4,4);
y(:,1)=-y(:,1);
y(:,2)=-y(:,2);
y=reshape(y,ndim,1);
% Copyright (C) 2006-2007 Artan Borici.
% This program is a free software licensed under the terms of the GNU General Public License