examofrbf5.m

RBF神经网络应用于IRIS数据集的例子

close all;
clear;
clc;

SamNum=100;
TestSamNum=101;
InDim=1;
UnitNum=10;
Epoches=0;
E0=0.1;

%根据目标函数获得样本输入输出
rand('state',sum(100*clock));  %Resets it to a different state each time.
NoiseVar=0.1;
Noise=NoiseVar*randn(1,SamNum);
SamIn=8*rand(1,SamNum)-4;
SamOutNoNoise=1.1*(1-SamIn+2*SamIn.^2).*exp(-0.5*SamIn.^2);
SamOut=SamOutNoNoise;

TestSamIn=-4:0.08:4;
TestSamOut=1.1*(1-TestSamIn+2*TestSamIn.^2).*exp(-0.5*TestSamIn.^2);

figure(1)
grid
plot(SamIn,SamOut,'k+')
xlabel('Input x')
ylabel('Output y')

figure(2)
grid
plot(TestSamIn,TestSamOut,'k-')
xlabel('Input x')
ylabel('Output y')

figure(3)
grid
hold on
plot(SamIn,SamOut,'k+')
plot(TestSamIn,TestSamOut,'k-')
xlabel('Input x')
ylabel('Output y')
hold off


Centers=8*rand(InDim,UnitNum)-4;
SP=0.2*rand(InDim,UnitNum)+0.1;
W=0.2*rand(InDim,UnitNum)-0.1;
lrCent=0.001;
lrSP=0.001;
lrW=0.001;
ErrHistory=[];

for epoch=1:inf
    AllDist=dist(Centers',SamIn);
    SPMat=repmat(SP',1,SamNum);
    UnitOut=radbas(AllDist./SPMat);
    NetOut=W*UnitOut;
    Error=SamOut-NetOut;
    
    SSE=sumsqr(Error);
    
    ErrHistory=[ErrHistory SSE];
    
    if SSE<E0
        break
    end
    
    for i=1:UnitNum        
        Cent=sum(Error.*radbas(dist(Centers(:,i),SamIn)/SP(i)).*(SamIn-Centers(:,i)));
        SPsum=sum(Error.*radbas(dist(Centers(:,i),SamIn)/SP(i)).*dist(Centers(:,i),SamIn));
        Wsum=sum(Error.*radbas(dist(Centers(:,i),SamIn)/SP(i)));         
        CentGrad=Cent*W(i)/(SP(i)^2);
        SPGrad=SPsum*W(i)/(SP(i)^3);
        WGrad=Wsum;
        Centers(:,i)=Centers(:,i)+lrCent*CentGrad;
        SP(i)=SP(i)+lrSP*SPGrad;
        W(i)=W(i)+lrW*WGrad;
    end
    Epoches=Epoches+1;
end

%测试
TestDistance=dist(Centers',TestSamIn);
TestSpreadsMat=repmat(SP',1,TestSamNum);
TestHiddenUnitOut=radbas(TestDistance./TestSpreadsMat);
TestNNOut=W*TestHiddenUnitOut;
figure(4)
plot(TestSamIn,TestNNOut,'k-');
figure(5)
hold on 
plot(TestSamIn,TestNNOut-TestSamOut,'r-');
plot(TestSamIn,TestSamOut,'c-')
plot(TestSamIn,TestNNOut,'b-');     
hold off
%绘制误差曲线
Num=length(ErrHistory);
figure(6)
hold on
plot(1:Num,ErrHistory,'k-')
hold off
grid