function y = stepfun(t,to)
%STEPFUN  Unit step function.
%
%   STEPFUN(T,T0), where T is a monotonically increasing vector,
%   returns a vector the same length as T with zeros where T < T0
%   and ones where T >= T0.

%   J.N. Little 6-3-87
%   Copyright 1986-2002 The MathWorks, Inc. 
%   $Revision: 1.10 $  $Date: 2002/04/04 15:15:45 $

[m,n] = size(t);
y = zeros(m,n);
i = find(t>=to);
if isempty(i)
    return
end
i = i(1);
if m == 1
    y(i:n) = ones(1,n-i+1);
else
    y(i:m) = ones(m-i+1,1);
end