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! W, a+ |3 e; Z% [. J% }( HRBF_cluster:
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% 1.基于聚类的RBF 网设计算法 5 l% z p9 U( Z1 X0 C
% 一维输入,一维输出,逼近效果很好!
4 k. k5 Q, n3 g& W1 n; PSamNum = 100; % 总样本数 # e6 L* U, a/ i1 y& w5 Y3 u
TestSamNum = 101; % 测试样本数
/ c5 d9 R5 H3 g. }InDim = 1; % 样本输入维数
- ^& X: C& ?. a( XClusterNum = 10; % 隐节点数,即聚类样本数 3 O( ?) Y. ?/ H$ G3 W
Overlap = 1.0; % 隐节点重叠系数 & B q& U* o' S) f& f$ G$ _
. g2 X3 l3 p( o! j _8 f% 根据目标函数获得样本输入输出 , z4 y$ S; _% W* p1 d
rand('state',sum(100*clock))
3 x- g9 O0 a4 F' b( n! h* s* {' _, l" GNoiseVar = 0.1;
8 x( \" j2 y3 a- @7 j2 w+ x$ `, VNoise = NoiseVar*randn(1,SamNum); ( e" w/ b# H$ M& O7 k! T
SamIn = 8*rand(1,SamNum)-4; 0 h" Q& k9 B- p+ F
SamOutNoNoise = 1.1*(1-SamIn+2*SamIn.^2).*exp(-SamIn.^2/2); 4 X4 E' K9 {3 B" h& ~! p4 d; j
SamOut = SamOutNoNoise + Noise; " v8 ~8 x* U3 K7 w
% M4 [1 Q4 |$ M% Q# X/ hTestSamIn = -4:0.08:4; w1 M8 V8 h4 b9 b* W2 p1 s
TestSamOut = 1.1*(1-TestSamIn+2*TestSamIn.^2).*exp(-TestSamIn.^2/2); ( J! I( q# A9 u' ~+ {, C; R
1 x/ b2 Z$ e0 `figure
7 H+ e6 L7 z. D: J# H. V- }7 fhold on & H. T1 {( B* T6 C0 c2 F' B
grid 1 X) W) T% w" w r: F4 |/ y
plot(SamIn,SamOut,'k+')
2 J; I5 u6 s& ?1 X$ Eplot(TestSamIn,TestSamOut,'r--') . J1 [* S' V% Q5 \
xlabel('Input x'); : O- U9 [3 G, Q& v
ylabel('Output y'); 5 h6 H8 c' Y1 O$ f1 ~1 Z& o. c
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Centers = SamIn(:,1:ClusterNum); 4 @' {' F5 W3 X# ]
3 G3 a" N# \- \- i7 f1 L1 vNumberInClusters = zeros(ClusterNum,1); % 各类中的样本数,初始化为零 ; y1 e9 h' Z( o; G" m: k+ x8 o g
IndexInClusters = zeros(ClusterNum,SamNum); % 各类所含样本的索引号 & i$ C6 W. A' l
while 1,
( ~7 O$ E6 ^4 E% y% Z# |NumberInClusters = zeros(ClusterNum,1); % 各类中的样本数,初始化为零 w2 h& @- B+ U- v# [/ |" `
IndexInClusters = zeros(ClusterNum,SamNum); % 各类所含样本的索引号 ! {2 _# ~' f5 M$ [+ k
7 L; k9 o1 e( O5 e/ s* F# R% 按最小距离原则对所有样本进行分类
9 j! L$ z, T1 [for i = 1:SamNum
! h% ~% h" Y% Y, b8 V, v) _AllDistance = dist(Centers',SamIn(:,i)); . N7 o' _4 j" o9 [, X. k: K/ I
[MinDist,Pos] = min(AllDistance);
2 V. |/ U" q% U( T4 v( M( ]NumberInClusters(Pos) = NumberInClusters(Pos) + 1; 5 F/ T7 _; p1 y. d1 o# y7 V
IndexInClusters(Pos,NumberInClusters(Pos)) = i; 8 i1 K0 |! r8 `' k7 T6 Y% B* |% n# e8 T
end 0 y6 ]9 @8 _( _+ N3 N
% 保存旧的聚类中心
) E3 L/ A& S8 A# ^OldCenters = Centers; " z: G; W$ A5 L+ X0 W$ j6 Y
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for i = 1:ClusterNum ' m9 V/ X% X. R+ R; u+ X) u
Index = IndexInClusters(i,1:NumberInClusters(i));
2 j% S L, K' Y" ^" C4 MCenters(:,i) = mean(SamIn(:,Index)')';
; E: {4 l% F3 V6 Send
* N( ?, P, k( }/ e. q% R, _/ [" b% 判断新旧聚类中心是否一致,是则结束聚类
$ o, f8 f$ N1 |# u8 x0 }EqualNum = sum(sum(Centers==OldCenters)); ) q. W! W/ L+ ]; i! e) I! \% o
if EqualNum == InDim*ClusterNum, ( o. f6 Z) l. B1 l% q$ l" O, q0 p" L
break, 2 {7 Z5 @4 Y3 \( d
end
& H# x" j: [% f! A& P. [5 H& ^end
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% 计算各隐节点的扩展常数(宽度) " S8 E+ b$ L! d) j
AllDistances = dist(Centers',Centers); % 计算隐节点数据中心间的距离(矩阵)
7 U# w1 `- z) @ x5 pMaximum = max(max(AllDistances)); % 找出其中最大的一个距离
2 T# t0 F, u- U3 j n% g ?for i = 1:ClusterNum % 将对角线上的0 替换为较大的值 % b% {( q2 w; O5 e' H
AllDistances(i,i) = Maximum+1;
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Spreads = Overlap*min(AllDistances)'; % 以隐节点间的最小距离作为扩展常数 9 u* K8 ^; y) e4 k: P3 {3 Z
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% 计算各隐节点的输出权值 " M! f) T" o I* {
Distance = dist(Centers',SamIn); % 计算各样本输入离各数据中心的距离
7 y" u4 V1 k; Q ]4 K& HSpreadsMat = repmat(Spreads,1,SamNum);
3 D8 Y1 S% o+ n3 R, {HiddenUnitOut = radbas(Distance./SpreadsMat); % 计算隐节点输出阵 - x4 Z. }7 R$ ]8 e
HiddenUnitOutEx = [HiddenUnitOut' ones(SamNum,1)]'; % 考虑偏移
: F4 L( X5 s1 }8 b) E UW2Ex = SamOut*pinv(HiddenUnitOutEx); % 求广义输出权值
4 F# s: E- _6 ~6 ~1 M6 B9 HW2 = W2Ex(:,1:ClusterNum); % 输出权值
2 A: S4 e0 L& T9 j8 ]0 K- u, u5 GB2 = W2Ex(:,ClusterNum+1); % 偏移
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3 h* x# c- y5 w( `% 测试 5 ^& m- d' n6 g, f. l/ T5 J
TestDistance = dist(Centers',TestSamIn); , }# d5 s0 j# c7 J6 h) p. c
TestSpreadsMat = repmat(Spreads,1,TestSamNum);
9 L0 A, x6 X; x' s% ZTestHiddenUnitOut = radbas(TestDistance./TestSpreadsMat);
9 k6 z# Y0 k. kTestNNOut = W2*TestHiddenUnitOut+B2;
2 D& w9 x9 w2 \' d4 Y/ o& v: l1 qplot(TestSamIn,TestNNOut,'b-')
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