function f=unc_n1_03(x)
%reference:
%note that you can get the formulation of unc_n1_03 from some
%aritcles,such as
%
%
%algorithm:
%below code is  edited according to 
%
%
% solution:
% where the bounds are -10<=x<=25,
% The global minimum is at x*=21,and f(x*)= -1.3679;



%Copyright:
% programmers:oiltowater.
% It comply with the GPL2.0
% Copyright 2006  oiltowater 


if x<=20
    f= -exp(-(x/20)^2);
else
    f= -exp(-1)+(x-20)*(x-22);
end