function d=dnullwf(code,w,p,z)
%DNULLWF Null weight derivative function.
%
%	Syntax
%	
%	  dZ_dP = dnullwf('p',W,P,Z)
%	  dZ_dW = dnullwf('w',W,P,Z)
%
%	Warning!!
%
%	  This function may be altered or removed in future
%	  releases of the Neural Network Toolbox. We recommend
%	  you do not write code which calls this function.

% Mark Beale, 11-31-97
% Copyright (c) 1992-1998 by The MathWorks, Inc.
% $Revision: 1.4 $

switch code
  case 'p', d = zeros(size(w));
  case 'w', d = zeros(size(p));
  otherwise, error(['Unrecognized code.'])
end
