% heaviside
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%
% DESCRIPTION: Heaviside function. In zero it returns NaN.
%
% VERSION:     $Id: heaviside.m,v 1.1 2011/06/01 13:09:14 congedo Exp $
%
% HISTORY:     31-05-2011 G. Congedo
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function y = heaviside(x)
  y = +(x>=0);
  y(x==0) = NaN;
end