1 简介
针对ELM预测性能受其初始权值和阈值的影响,运用WOA算法对ELM的初始权值和阈值进行优化选择,优化数据分类效果。



2 部分代码
%_________________________________________________________________________%% 鲸鱼优化算法 %%_________________________________________________________________________%% The Whale Optimization Algorithmfunction [Leader_score,Leader_pos,Convergence_curve]=WOA(SearchAgents_no,Max_iter,lb,ub,dim,fobj)% initialize position vector and score for the leaderLeader_pos=zeros(1,dim);Leader_score=inf; %change this to -inf for maximization problems%Initialize the positions of search agentsPositions=initialization(SearchAgents_no,dim,ub,lb);Convergence_curve=zeros(1,Max_iter);t=0;% Loop counter% Main loopwhile t<Max_iterfor i=1:size(Positions,1)% Return back the search agents that go beyond the boundaries of the search spaceFlag4ub=Positions(i,:)>ub;Flag4lb=Positions(i,:)<lb;Positions(i,:)=(Positions(i,:).*(~(Flag4ub+Flag4lb)))+ub.*Flag4ub+lb.*Flag4lb;% Calculate objective function for each search agentfitness=fobj(Positions(i,:));% Update the leaderif fitness<Leader_score % Change this to > for maximization problemLeader_score=fitness; % Update alphaLeader_pos=Positions(i,:);endenda=2-t*((2)/Max_iter); % a decreases linearly fron 2 to 0 in Eq. (2.3)% a2 linearly dicreases from -1 to -2 to calculate t in Eq. (3.12)a2=-1+t*((-1)/Max_iter);% Update the Position of search agentsfor i=1:size(Positions,1)r1=rand(); % r1 is a random number in [0,1]r2=rand(); % r2 is a random number in [0,1]A=2*a*r1-a; % Eq. (2.3) in the paperC=2*r2; % Eq. (2.4) in the paperb=1; % parameters in Eq. (2.5)l=(a2-1)*rand+1; % parameters in Eq. (2.5)p = rand(); % p in Eq. (2.6)for j=1:size(Positions,2)if p<0.5if abs(A)>=1rand_leader_index = floor(SearchAgents_no*rand()+1);X_rand = Positions(rand_leader_index, :);D_X_rand=abs(C*X_rand(j)-Positions(i,j)); % Eq. (2.7)Positions(i,j)=X_rand(j)-A*D_X_rand; % Eq. (2.8)elseif abs(A)<1D_Leader=abs(C*Leader_pos(j)-Positions(i,j)); % Eq. (2.1)Positions(i,j)=Leader_pos(j)-A*D_Leader; % Eq. (2.2)endelseif p>=0.5distance2Leader=abs(Leader_pos(j)-Positions(i,j));% Eq. (2.5)Positions(i,j)=distance2Leader*exp(b.*l).*cos(l.*2*pi)+Leader_pos(j);endendendt=t+1;Convergence_curve(t)=Leader_score;end
3 仿真结果


4 参考文献
[1]林绪骞. 基于鲸鱼算法优化ELM的新疆铁路网规模预测[J]. 现代科学仪器, 2019(2):5.
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