【PNN分类】基于灰狼鹰算法优化pnn神经网络实现数据分附matlab代码

1 简介

概率神经网络(Probabilistic Neural Network,简称PNN)是利用贝叶斯定理和基于风险最小的贝叶斯决策规则对新样本进行分类的神经网络,具有训练时间短且不易收敛到局部极值的优点,但是传统PNN采用相同平滑系数容易导致识别率低和误分类的问题,其次平滑系数对分类结果影响巨大并且难以确定,模式层神经元数目由训练样本数目确定,当训练样本集规模巨大时,导致网络结构复杂。本文采用灰狼算法选择PNN网络的平滑系数向量并优化PNN的网络结构.

2 部分代码

​% Grey Wolf Optimizerfunction [Alpha_score,Alpha_pos,Convergence_curve]=GWO(SearchAgents_no,Max_iter,lb,ub,dim,fobj)​% initialize alpha, beta, and delta_posAlpha_pos=zeros(1,dim);Alpha_score=inf; %change this to -inf for maximization problems​Beta_pos=zeros(1,dim);Beta_score=inf; %change this to -inf for maximization problems​Delta_pos=zeros(1,dim);Delta_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);​l=0;% Loop counter​% Main loopwhile l<Max_iter    for i=1:size(Positions,1)                 % Return back the search agents that go beyond the boundaries of the search space        Flag4ub=Positions(i,:)>ub;        Flag4lb=Positions(i,:)<lb;        Positions(i,:)=(Positions(i,:).*(~(Flag4ub+Flag4lb)))+ub.*Flag4ub+lb.*Flag4lb;                               % Calculate objective function for each search agent        fitness=fobj(Positions(i,:));                % Update Alpha, Beta, and Delta        if fitness<Alpha_score             Alpha_score=fitness; % Update alpha            Alpha_pos=Positions(i,:);        end                if fitness>Alpha_score && fitness<Beta_score             Beta_score=fitness; % Update beta            Beta_pos=Positions(i,:);        end                if fitness>Alpha_score && fitness>Beta_score && fitness<Delta_score             Delta_score=fitness; % Update delta            Delta_pos=Positions(i,:);        end    end            a=2-l*((2)/Max_iter); % a decreases linearly fron 2 to 0        % Update the Position of search agents including omegas    for i=1:size(Positions,1)        for j=1:size(Positions,2)                                        r1=rand(); % r1 is a random number in [0,1]            r2=rand(); % r2 is a random number in [0,1]                        A1=2*a*r1-a; % Equation (3.3)            C1=2*r2; % Equation (3.4)                        D_alpha=abs(C1*Alpha_pos(j)-Positions(i,j)); % Equation (3.5)-part 1            X1=Alpha_pos(j)-A1*D_alpha; % Equation (3.6)-part 1                                   r1=rand();            r2=rand();                        A2=2*a*r1-a; % Equation (3.3)            C2=2*r2; % Equation (3.4)                        D_beta=abs(C2*Beta_pos(j)-Positions(i,j)); % Equation (3.5)-part 2            X2=Beta_pos(j)-A2*D_beta; % Equation (3.6)-part 2                               r1=rand();            r2=rand();                         A3=2*a*r1-a; % Equation (3.3)            C3=2*r2; % Equation (3.4)                        D_delta=abs(C3*Delta_pos(j)-Positions(i,j)); % Equation (3.5)-part 3            X3=Delta_pos(j)-A3*D_delta; % Equation (3.5)-part 3                                     Positions(i,j)=(X1+X2+X3)/3;% Equation (3.7)                    end    end    l=l+1;        Convergence_curve(l)=Alpha_score;end

3 仿真结果

4 参考文献

[1]李敏, 余正涛. 结合概率型神经网络(PNN)和学习矢量量化(LVQ)算法的文本分类方法[J]. 计算机系统应用, 2012.

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