function epsn = ReduceBoundary(eF, k, MaxK, cp)
% The shrink of the dynamic constraint boundary

%------------------------------- Copyright --------------------------------
% Copyright (c) 2023 BIMK Group. You are free to use the PlatEMO for
% research purposes. All publications which use this platform or any code
% in the platform should acknowledge the use of "PlatEMO" and reference "Ye
% Tian, Ran Cheng, Xingyi Zhang, and Yaochu Jin, PlatEMO: A MATLAB platform
% for evolutionary multi-objective optimization [educational forum], IEEE
% Computational Intelligence Magazine, 2017, 12(4): 73-87".
%--------------------------------------------------------------------------

% This function is written by Ruwang Jiao
    
    z        = 1e-8;
    Nearzero = 1e-15;
    B        = MaxK./power(log((eF + z)./z), 1.0./cp);
    B(B==0)  = B(B==0) + Nearzero;
    f        = eF.* exp( -(k./B).^cp );
    tmp      = find(abs(f-z) < Nearzero);
    f(tmp)   = f(tmp).*0 + z;
    epsn     = f - z;
    epsn(epsn<=0) = 0;
end