%======================================================================
        % Copyright (C) 2005
        % All rights reserved.

        % File name: myself.m 
        % Notes:     應用1-M-1網絡對 2D Mexican Hat 進行函數逼近
        %            檢驗反向傳播的逼近效果
        %            最簡單的簡單的梯度下降算法

        % Version: 1.0
        % Author:  bug zhang
        % Date:    2005.1
        %======================================================================
        
        close all	%關閉所有的窗口
        clear all	%清除所有的變量
        k=input('取樣點數=k,k=[5000]   ');
        if isempty(k),
           k=5000;
        end;
        L=input('最大隱層神經元個數=L,L=[40]   ');
        if isempty(k),
           L=40;
        end;
        S=input('歸一化參數=S,S=[0.5]   ');
        if isempty(k),
           S=0.5;
        end;
     

        X=4*pi*rand(1,k)-2*pi;
        Y=sin(abs(X))./(abs(X));
       
        
        net=newrb(X,Y,0,S,L,5);
        
        
        X2=linspace(0,4*pi,1000)-2*pi;
        Y2=sin(abs(X2))./(abs(X2));
        
        X1=4*pi*rand(1,100)-2*pi;
        Y1=sin(abs(X1))./(abs(X1));
        R=sim(net,X1);
        
        figure(2)
        plot(X2,Y2,'-k',X1,R,'.b',X1,Y1,'+r')
        grid on
        xlabel('x in [0,10]')
        ylabel('y=sin(x).*exp(-x)')
        title('簡單bp網絡應用于函數逼近')