clear,clc;
SamNum = 100;                       % 訓練樣本數
%TargetSamNum = length(TargetIn);                 % 測試樣本數
InDim = 1;                          % 樣本輸入維數
UnitNum = 10;                       % 隱節點數
MaxEpoch = 2500;                    % 最大訓練次數
E0 = 0.9;                           %目標誤差

% 根據目標函數獲得樣本輸入輸出
rand('state',sum(100*clock))
NoiseVar = 0.1;
Noise = NoiseVar*randn(1,SamNum);
SamIn = 8*rand(1,SamNum)-4;
SamOutNoNoise = 1.1*(1-SamIn+2*SamIn.^2).*exp(-SamIn.^2/2);
SamOut = SamOutNoNoise + Noise;

TargetIn = -4:0.08:4;
TargetOut = 1.1*(1-TargetIn+2*TargetIn.^2).*exp(-TargetIn.^2/2);

TargetSamNum = length(TargetIn);                 % 測試樣本數

figure
hold on
grid
plot(SamIn,SamOut,'b+')
plot(TargetIn,TargetOut,'r--')
xlabel('Input x');
ylabel('Output y');

Center = 8*rand(InDim,UnitNum)-4;      %Data Center
SP = 0.2*rand(1,UnitNum)+0.1;          %Spread Constant
W = 0.2*rand(1,UnitNum)-0.1;           %Weigh Matrix

lrCent = 0.001;						        % 隱節點數據中心學習系數
lrSP = 0.001;						        % 隱節點擴展常數學習系數
lrW = 0.001;						        % 隱節點輸出權值學習系數
ErrHistory = [];                            % 用于記錄每次參數調整后的訓練誤差
for epoch = 1:MaxEpoch
    AllDist = dist(Center',SamIn);
    SPMat = repmat(SP',1,SamNum);
    UnitOut = radbas(AllDist./SPMat);
    NetOut = W*UnitOut;
    Error = SamOut-NetOut;
    
    %停止學習判斷
    SSE = sumsqr(Error);

    % 記錄每次權值調整后的訓練誤差
    ErrHistory = [ErrHistory SSE];

    if SSE<E0, break, end
    
    for i = 1:UnitNum
        CentGrad = (SamIn-repmat(Center(:,i),1,SamNum))...
                  *(Error.*UnitOut(i,:)*W(i)/(SP(i)^2))';
        SPGrad = AllDist(i,:).^2*(Error.*UnitOut(i,:)*W(i)/(SP(i)^3))';
        WGrad = Error*UnitOut(i,:)';

        Center(:,i) = Center(:,i) + lrCent*CentGrad;
        SP(i) = SP(i) + lrSP*SPGrad;
        W(i) = W(i) + lrW*WGrad;
    end
end 

% 測試
TestDistance = dist(Center',TargetIn);
TestSpreadsMat = repmat(SP',1,TargetSamNum);
TestHiddenUnitOut = radbas(TestDistance./TestSpreadsMat);
TestNNOut = W*TestHiddenUnitOut;
plot(TargetIn,TestNNOut,'k-');legend('Sample Data','Desired Curve','RBF NN Curve');

% 繪制學習誤差曲線
figure
hold on
grid
[xx,Num] = size(ErrHistory); 
plot(1:Num,ErrHistory,'k-');