机器学习实验报告.docx

机器学习实验报告实验一、ID3算法1.实验目的：了解并掌握ID3算法。2.实验内容：编程实现ID3算法。3.实验结果。实验程序：function tree=ID3(T,N_V)m,n=size(T);C=zeros(1,n);for i=1:n C(i)=max(T(:,i);endPe=zeros(1,C(n);Ee=0;for i=1:C(n) Pe(i)=length(find(T(:,n)=i)/m; if Pe(i)=0 Ee=Ee-(Pe(i)*log2(Pe(i); endend P=zeros(n-1,max(C(1:n-1),C(n);E=zeros(1,n-1);G=zeros(1,n-1);nj=0;for i=1:n-1 for j=1:C(i) nj=length(find(T(:,i)=j); for k=1:C(n) counter=0; for ii=1:m if(T(ii,i)=j&T(ii,n)=k) counter=counter+1; end end P(i,j,k)=counter/nj; if P(i,j,k)=0 E(i)=E(i)-(nj/m)*P(i,j,k)*log2(P(i,j,k); end end end G(i)=Ee-E(i);end best=0;BestTag=0;for i=1:n-1 if G(i)best best=G(i); BestTag=i; endendtree.rname=N_V(1,BestTag);for ii=1:C(BestTag) temp=0; tree.branchii=; tree.bnameii=; for i=1:m if (T(i,BestTag)=ii) if (temp=0) temp=T(i,n); elseif (temp=T(i,n) tree.branchii=ID3(T(T(:,BestTag)=ii,:),N_V); tree.bnameii=N_V(ii+1,BestTag); break; end end end if isempty(tree.bnameii) tree.branchii=N_V(temp+1,n); tree.bnameii=N_V(ii+1,BestTag); endend 对于下表：DayOutlookTemperatureHumidityWindyPlayTennisD1SunnyHotHighWeakNoD2SunnyHotHighStrongNoD3OvercastHotHighWeakYesD4RainMildHighWeakYesD5RainCoolNormalWeakYesD6RainCoolNormalStrongNoD7OvercastCoolNormalStrongYesD8SunnyMildHighWeakNoD9SunnyCoolNormalWeakYesD10RainMildNormalWeakYesD11SunnyMildNormalStrongYesD12OvercastMildHighStrongYesD13OvercastHotNormalWeakYesD14RainMildHighStrongNo转化为程序输入：N_V=outlook temperature humidity windy class; sunny hot high weak no; overcast mild normal strong yes; rain cool NAS NAS NAST= 1 1 1 1 1; 1 1 1 2 1; 2 1 1 1 2; 3 2 1 1 2; 3 3 2 1 2; 3 3 2 2 1; 2 3 2 2 2; 1 2 1 1 1; 1 3 2 1 2; 3 2 2 1 2; 1 2 2 2 2; 2 2 1 2 2; 2 1 2 1 2;3 2 1 2 1;O=ID3(T,N_V);其中：第一列1、2、3分别对应sunny、overcast、rain；第二列1、2、3分别对应hot、mild、cool；第三列1、2分别对应high、normal、cool；第四列1、2分别对应weak、strong；第五列1、2分别对应no、yes。程序输出：实验二、BP神经网络1.实验目的：了解并掌握BP神经网络。2.实验内容：编程实现BP神经网络。3.实验结果。实验程序：Wac=0.1;Wbc=0.1;Wc0=0.1;Wcd=0.1;Wd0=0.1;L=0.3;I=0.9;X=1 0;0 1;T=1 0;DWcd=0;DWd0=0;DWac=0;DWbc=0;DWc0=0;N=1000;OUT=zeros(2,N);for i=1:N Sc(1)=Wac*X(1,1)+Wbc*X(1,2)+Wc0; Oc(1)=1/(1+exp(-Sc(1); Sd(1)=Wcd*Oc(1)+Wd0; Od(1)=1/(1+exp(-Sd(1); Ed(1)=Od(1)*(1-Od(1)*(T(1)-Od(1); Ec(1)=Oc(1)*(1-Oc(1)*Ed(1); DWcd=L*Ed(1)*Oc(1)+I*DWcd; DWd0=L*Ed(1)+I*DWd0; DWac=L*Ec(1)*X(1,1)+I*DWac; DWbc=L*Ec(1)*X(1,2)+I*DWbc; DWc0=L*Ec(1)+I*DWc0; Wcd=Wcd+DWcd; Wd0=Wd0+DWd0; Wac=Wac+DWac; Wbc=Wbc+DWbc; Wc0=Wc0+DWc0; OUT(1,i)=Od(1); Sc(2)=Wac*X(2,1)+Wbc*X(2,2)+Wc0; Oc(2)=1/(1+exp(-Sc(2); Sd(2)=Wcd*Oc(2)+Wd0; Od(2)=1/(1+exp(-Sd(2); Ed(2)=Od(2)*(1-Od(2)*(T(2)-Od(2); Ec(2)=Oc(2)*(1-Oc(2)*Ed(2); DWcd=L*Ed(2)*Oc(2)+I*DWcd; DWd0=L*Ed(2)+I*DWd0; DWac=L*Ec(2)*X(2,1)+I*DWac; DWbc=L*Ec(2)*X(2,2)+I*DWbc; DWc0=L*Ec(2)+