|
|
EDA365欢迎您登录!
您需要 登录 才可以下载或查看,没有帐号?注册
x
本帖最后由 thinkfunny 于 2020-10-22 15:41 编辑
8 s. M% z; J$ P: J r+ n- F( U: J7 A5 I8 g% L* b: \
这一篇是Xue Bing在一区cybernetics发的论文,里面提出了两个多目标PSO特征选择算法,一个是NSPSO另一个是CMDPSO。其中NSPSO是参考了NSGA2的框架和思想。
! F! |- P* h; [+ |/ k J% b" X
4 W0 ^+ ^! V. n7 R3 Z* X& j伪代码
$ Y& }0 K- y* z# r* ?. @/ d
$ A1 _; q, d- L% J具体流程: s/ T/ N6 ?) s6 ~9 n
- ①划分数据集为测试集和训练集
- ②初始化PSO算法
- ③迭代开始
- ④计算两个目标值(论文中是特征数和错误率)
- ⑤非支配排序
- ⑥拥挤距离度量并排序
- ⑥对每个粒子从第一前沿面选择一个粒子作为gbest,更新当前粒子
- ⑦调整粒子群
- ⑧迭代结束返回' f% S( ~$ a2 m* \. i1 O
$ g/ r. }" I6 v; ]( c6 ]
MATLAB实现:
* c8 R8 d( Z V! eNSPSO:+ [/ c. {0 V% x) V
, z1 b) c4 u) J- n- Q- `注意其中FSKNN是我的问题的评价函数,包含两个目标值,都存入到pfitness中) B" l' h2 r, |" M1 f
; Z9 g, s+ \/ s0 a- function [solution,time,pop,pfitness,site,LeaderAVE] = NSPSO(train_F,train_L)
- tic
- global maxFES
- dim = size(train_F,2);
- FES = 1;
- sizep = 30;
- pop = rand(sizep,dim);
- popv = rand(sizep,dim);
- pfitness = zeros(sizep,2);
- LeaderAVE = zeros(1,2);
- while FES <maxFES
- Off_P = zeros(sizep,dim);
- Off_V = zeros(sizep,dim);
- ofitness = zeros(sizep,2);
- for i=1:sizep
- [pfitness(i,1),pfitness(i,2)] = FSKNN(pop(i,: ),i,train_F,train_L);
- end
- Front = NDSort(pfitness(:,1:2),sizep);
- [~,rank] = sortrows([Front',-CrowdingDistance(pfitness,Front)']);
- LeaderSet = rank(1:10);
- solution = pfitness(LeaderSet,: );
- LeaderAVE(1) = mean(solution(:,1));
- LeaderAVE(2) = mean(solution(:,2));
- for i = 1:sizep
- good = LeaderSet(randperm(length(LeaderSet),1));
- r1 = rand(1,dim);
- r2 = rand(1,dim);
- Off_V(i,: ) = r1.*popv(i,: ) + r2.*(pop(good,: )-pop(i,: ));
- Off_P(i,: ) = pop(i,: ) + Off_V(i,: );
- end
- for i=1:sizep
- [ofitness(i,1),ofitness(i,2)] = FSKNN(Off_P(i,: ),i,train_F,train_L);
- end
- temppop = [pop;Off_P];
- tempv = [popv;Off_V];
- tempfiness = [pfitness;ofitness];
- [FrontNO,MaxFNO] = NDSort(tempfiness(:,1:2),sizep);
- Next = false(1,length(FrontNO));
- Next(FrontNO<MaxFNO) = true;
- PopObj = tempfiness;
- fmax = max(PopObj(FrontNO==1,: ),[],1);
- fmin = min(PopObj(FrontNO==1,: ),[],1);
- PopObj = (PopObj-repmat(fmin,size(PopObj,1),1))./repmat(fmax-fmin,size(PopObj,1),1);
- % Select the solutions in the last front
- Last = find(FrontNO==MaxFNO);
- del = Truncation(PopObj(Last,: ),length(Last)-sizep+sum(Next));
- Next(Last(~del)) = true;
- % Population for next generation
- pop = temppop(Next,: );
- popv = tempv(Next,: );
- pfitness = tempfiness(Next,: );
- fprintf('GEN: %2d Error: %.4f F:%.2f\n',FES,LeaderAVE(1),LeaderAVE(2));
- FES = FES + 1;
- end
- [FrontNO,~] = NDSort(pfitness(:,1:2),sizep);
- site = find(FrontNO==1);
- solution = pfitness(site,: );
- LeaderAVE(1) = mean(solution(:,1));
- LeaderAVE(2) = mean(solution(:,2));
- toc
- time = toc;
- end S" Q. H' a2 n
" T1 y8 \0 r& ?" I ~- a; _/ a8 D
- T0 b4 C8 j6 [拥挤距离代码:( H% d+ f! V' d. ]* ] F& G
7 e3 B* z- _1 Z2 c# D; t) H) u5 L- function CrowdDis = CrowdingDistance(PopObj,FrontNO)
- % Calculate the crowding distance of each solution front by front
- % Copyright 2015-2016 Ye Tian
- [N,M] = size(PopObj);
- CrowdDis = zeros(1,N);
- Fronts = setdiff(unique(FrontNO),inf);
- for f = 1 : length(Fronts)
- Front = find(FrontNO==Fronts(f));
- Fmax = max(PopObj(Front,: ),[],1);
- Fmin = min(PopObj(Front,: ),[],1);
- for i = 1 : M
- [~,Rank] = sortrows(PopObj(Front,i));
- CrowdDis(Front(Rank(1))) = inf;
- CrowdDis(Front(Rank(end))) = inf;
- for j = 2 : length(Front)-1
- CrowdDis(Front(Rank(j))) = CrowdDis(Front(Rank(j)))+(PopObj(Front(Rank(j+1)),i)-PopObj(Front(Rank(j-1)),i))/(Fmax(i)-Fmin(i));
- end
- end
- end
- end
S2 g0 y e' Q3 f 6 s: e# ]% O( h a1 b$ A6 Z. J
' W: v, v/ @! G2 c6 w
Truncation.m代码:
7 q5 |, g( c$ v' x1 M) P' J( d, \8 J1 h4 O
- function Del = Truncation(PopObj,K)
- % Select part of the solutions by truncation
- N = size(PopObj,1);
- %% Truncation
- Distance = pdist2(PopObj,PopObj);
- Distance(logical(eye(length(Distance)))) = inf;
- Del = false(1,N);
- while sum(Del) < K
- Remain = find(~Del);
- Temp = sort(Distance(Remain,Remain),2);
- [~,Rank] = sortrows(Temp);
- Del(Remain(Rank(1))) = true;
- end
- end: e0 B5 }. R& l
) F6 C/ P& C* ^8 l! N/ J" F
% F+ h6 w0 e# i* c% H3 G 9 v. u8 [& p/ y$ H/ d% h" g
|
|