You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: TREE4.m
    path of file: ./repos/PlatEMO/PlatEMO/Problems/Multi-objective optimization/TREE
    
    the code of the file until where you have to start completion: classdef TREE4 < PROBLEM
% <multi> <real> <large/none> <constrained> <expensive/none>
% The time-varying ratio er
    
function PopObj = CalObj(obj,PopDec)
            N      = size(PopDec,1);
            KP     = size(obj.Data,2);
            [T,K]  = size(obj.Mean);
            PopDec = reshape(PopDec,N,T,K) + repmat(reshape(obj.Mean,1,T,K),N,1,1);
            PopObj = zeros(N,obj.M);
            % First objective
            eA1 = abs(repmat(reshape(obj.Data(:,1:end