function w = uminus(w)
   %-  Unary minus for waveforms.
   %   -A negates the elements of A.
   %
   %   B = UMINUS(W) is called for the syntax '-W' when W is an waveform.
   
   % AUTHOR: Celso Reyes, Geophysical Institute, Univ. of Alaska Fairbanks
   % $Date$
   % $Revision$
   
   for n=1:numel(w)
      w(n).data = -w(n).data;
   end
end