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/ ]& P6 w/ o' @7 M5 N7 aRBF_cluster:
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% 1.基于聚类的RBF 网设计算法
& y7 i* P9 G( n1 k- d% 一维输入,一维输出,逼近效果很好! % h( @) z& K2 _' N" Q
SamNum = 100; % 总样本数 3 _9 a/ R: p( ~7 u4 w
TestSamNum = 101; % 测试样本数 9 ~# a! @* l7 E4 ?) [) }- w
InDim = 1; % 样本输入维数 & |: D6 {: y4 r' q/ J. B* S
ClusterNum = 10; % 隐节点数,即聚类样本数 2 s- E9 q* R" D- B% M, e
Overlap = 1.0; % 隐节点重叠系数
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% 根据目标函数获得样本输入输出 - l$ h. R; ^7 O1 x" D
rand('state',sum(100*clock)) % \) Y- }$ Y/ ?6 b( a
NoiseVar = 0.1;
+ v, \% Y# l7 e+ q- b( a8 RNoise = NoiseVar*randn(1,SamNum);
0 G+ N- z1 M$ r7 r$ |) M1 WSamIn = 8*rand(1,SamNum)-4; 8 { b1 G, @$ R5 Y+ w% n3 F
SamOutNoNoise = 1.1*(1-SamIn+2*SamIn.^2).*exp(-SamIn.^2/2);
+ x+ t) j9 W4 JSamOut = SamOutNoNoise + Noise; 1 ]& N9 d( _ k% u4 y# v9 ^: D
+ l8 ]% j" w. p4 ^
TestSamIn = -4:0.08:4;
% ?4 ^1 y0 v( t: ^TestSamOut = 1.1*(1-TestSamIn+2*TestSamIn.^2).*exp(-TestSamIn.^2/2); 5 ~% Q# I _+ r. \ U
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figure * O9 T+ w# L9 O
hold on
! R! A, U2 V& O4 z( g- w* Rgrid
2 T# W% Y2 Z9 F% j8 cplot(SamIn,SamOut,'k+')
+ l" V0 U# t& T$ s5 v: J3 eplot(TestSamIn,TestSamOut,'r--') * Z6 {4 U: e2 j" b
xlabel('Input x');
! D% T5 n: q" x/ T/ x5 i& `ylabel('Output y');
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% u) v+ U2 P6 n2 k' d9 ?% sCenters = SamIn(:,1:ClusterNum);
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8 Y: s4 G$ }% q# y5 L6 d( LNumberInClusters = zeros(ClusterNum,1); % 各类中的样本数,初始化为零 2 `& D7 N# B8 W0 x, c
IndexInClusters = zeros(ClusterNum,SamNum); % 各类所含样本的索引号 % [ z* l9 E: K
while 1,
8 o! {% l7 Z7 ~, f. ?* UNumberInClusters = zeros(ClusterNum,1); % 各类中的样本数,初始化为零 ( m, d. J' C) W6 i' R3 f
IndexInClusters = zeros(ClusterNum,SamNum); % 各类所含样本的索引号 6 h& ~% S6 [- M
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% 按最小距离原则对所有样本进行分类 / U% q" z! @* r" U# z% ~
for i = 1:SamNum , V( W9 e+ {8 ?: m1 j
AllDistance = dist(Centers',SamIn(:,i));
5 ? Z. j; n! P w- k, D5 O! m[MinDist,Pos] = min(AllDistance); ( ^2 R& n) A. w5 o: |
NumberInClusters(Pos) = NumberInClusters(Pos) + 1;
0 ^8 y4 a) s R) [) rIndexInClusters(Pos,NumberInClusters(Pos)) = i; / ]* ?+ C2 V! M8 s+ N
end
# p# x7 b0 c. l% 保存旧的聚类中心 $ ` [$ x% f. z5 g
OldCenters = Centers;
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- K( }! N3 L+ K' V2 y4 S" tfor i = 1:ClusterNum ! v; ]) c- E1 t# x
Index = IndexInClusters(i,1:NumberInClusters(i)); y3 _4 [( h! x( n8 z f
Centers(:,i) = mean(SamIn(:,Index)')'; ( ]7 W; I% b) _+ T* z7 N
end ( Z. P( E. [+ M" Z2 C& G
% 判断新旧聚类中心是否一致,是则结束聚类 0 U" R3 H% M7 m0 T" v _6 d
EqualNum = sum(sum(Centers==OldCenters)); $ A0 O' S& ~) J# d% L0 f6 E
if EqualNum == InDim*ClusterNum,
4 J* _! A5 Q( b& O1 u7 G) xbreak,
$ y! X- E* }( Tend ( @6 f& |6 ~, y5 f9 K! Z! x& X
end
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% b% M8 r* c5 W" I K- M6 Q% 计算各隐节点的扩展常数(宽度) ! \& d, P' n+ M) }2 ^( ~
AllDistances = dist(Centers',Centers); % 计算隐节点数据中心间的距离(矩阵) 9 n& ~, P: @3 p8 j+ u2 h
Maximum = max(max(AllDistances)); % 找出其中最大的一个距离
) L7 Z+ i2 e$ u- Vfor i = 1:ClusterNum % 将对角线上的0 替换为较大的值 & ~# n) \. ~8 N) r& ~
AllDistances(i,i) = Maximum+1;
! \1 a* x& c* P9 t# R/ o/ e* ]end ; ?/ J- }- ?3 G8 f) ?
Spreads = Overlap*min(AllDistances)'; % 以隐节点间的最小距离作为扩展常数 $ z3 w2 c! \. T$ h2 M! L" s
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% 计算各隐节点的输出权值 2 L: @) v* p4 r; K& `
Distance = dist(Centers',SamIn); % 计算各样本输入离各数据中心的距离
- S# _: O) ^( h+ x7 u" KSpreadsMat = repmat(Spreads,1,SamNum); * O2 [* ]6 l( @4 i3 E/ N( b
HiddenUnitOut = radbas(Distance./SpreadsMat); % 计算隐节点输出阵 + l+ d2 C% F5 u! X; Y! g
HiddenUnitOutEx = [HiddenUnitOut' ones(SamNum,1)]'; % 考虑偏移 & Q V: I: } }+ d4 z
W2Ex = SamOut*pinv(HiddenUnitOutEx); % 求广义输出权值 5 g9 }8 @$ I# B! N( g: s
W2 = W2Ex(:,1:ClusterNum); % 输出权值
! i: j1 e$ A! d* W' \B2 = W2Ex(:,ClusterNum+1); % 偏移 , m) M/ k6 c2 z( t! C$ Y$ M- ^
) E1 H* I& J: y! a4 k+ D# o% 测试
" V, [, W- ]! |- ~: v" N' ZTestDistance = dist(Centers',TestSamIn); 3 x" Y" ?+ B2 e& N. a- e
TestSpreadsMat = repmat(Spreads,1,TestSamNum); 1 S7 p. T5 D/ U) }4 X
TestHiddenUnitOut = radbas(TestDistance./TestSpreadsMat);
1 A0 Y3 O6 B* c$ qTestNNOut = W2*TestHiddenUnitOut+B2;
( ]3 D& }8 A: J; Xplot(TestSamIn,TestNNOut,'b-') 1 \" E4 A' D! ~# p& y# r5 K8 h
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