MatlabCode_贝叶斯估计matlab_贝叶斯估计_

clear all; close all; L=128; % 帧长 NMax=500; %最大标签数 N=50:50:350;% 每次输入的标签数 Mento=2;%重复次数 for m=1:Mento for n=1:length(N) Tag=randint(N(n),1,L);% 将标签加入到帧中 % compute the idle, succesful and collision number NumIdle(m,n)=0; %空时隙数 NumSucc(m,n)=0; %成功时隙数 NumColl(m,n)=0; %冲突时隙数 for i=1:L Tmp=HowMany(Tag,i-1); %调用HowMangy函数统计时隙数 if Tmp==0 NumIdle(m,n)=NumIdle(m,n)+1; elseif Tmp==1 NumSucc(m,n)=NumSucc(m,n)+1; else NumColl(m,n)=NumColl(m,n)+1; end end NSet=(NumSucc(m,n)+2*NumColl(m,n)):NMax; % 最小标签数（空时隙数+二倍冲突时隙数） c=[NumIdle(m,n); NumSucc(m,n); NumColl(m,n)]; % 保存[空时隙数、成功时隙数、冲突时隙数] % estimation by maximizing the posteriori probability p=0; NSetSum=1:NMax; for i=1:length(NSetSum) fac=factorial(L)/(factorial(NumIdle(m,n))*factorial(NumSucc(m,n))*factorial(NumColl(m,n))); pIdle=(1-1/L)^(NSetSum(i)*NumIdle(m,n)); pSuc=((NSetSum(i)/L)*((1-1/L)^(NSetSum(i)-1)))^NumSucc(m,n); pColl=(1-(1-1/L)^NSetSum(i)-(NSetSum(i)/L)*((1-1/L)^(NSetSum(i)-1)))^NumColl(m,n); p(i)=fac*pIdle*pSuc*pColl; end [val,loc]=max(p); %取最大值 NPost(m,n)=NSetSum(loc); %取最大值对应的值 % estimation by MMSE yMMSE=0; for i=1:NMax yMMSE(i)=i*p(i); end NMMSE(m,n)=sum(yMMSE)/sum(p); % estimation by absolute Absolute=0; for i=1:NMax Absolute(i)=abs(sum(p(1:i))-sum(p(i:NMax))); end [Val,NAbsolute(m,n)]=min(Absolute); %取最小值 % relative error ErrorNPostNomean(m,n)=RelativeError(NPost(m,n),N(n)); ErrorNMMSENomean(m,n)=RelativeError(NMMSE(m,n),N(n)); ErrorNAbsoluteNomean(m,n)=RelativeError(NAbsolute(m,n),N(n)); end end % MeanNLBound=mean(NLBound); % MeanNSchoute=mean(NSchoute); % MeanNIdle=mean(NIdle); % MeanNPost=mean(NPost); % MeanNPostLess=mean(NPostLess); % MeanNVogt=mean(NVogt); % MeanNVogtLess=mean(NVogtLess); ErrorNMMSE=mean(ErrorNMMSENomean)*100; ErrorNAbsolute=mean(ErrorNAbsoluteNomean)*100; ErrorNPost=mean(ErrorNPostNomean)*100; figure(1); plot(N, ErrorNMMSE,'-ko','LineWidth',1,'MarkerEdgeColor','k','MarkerFaceColor','w','MarkerSize',5); hold on; plot(N, ErrorNAbsolute,'-k.','LineWidth',1,'MarkerEdgeColor','k','MarkerFaceColor','w','MarkerSize',5); hold on; plot(N, ErrorNPost,':k','LineWidth',1,'MarkerEdgeColor','k','MarkerFaceColor','w','MarkerSize',7); hold off; legend('贝叶斯均方估计','贝叶斯绝对估计','最大后验概率估计',2); % plot the legend % grid; % plot the grid xlabel('标签数,n'),ylabel('相对误差,ε(%)'); figure(2); plot(p,'-k','LineWidth',1,'MarkerEdgeColor','k','MarkerFaceColor','w','MarkerSize',5); hold on; xlabel('标签数'),ylabel('概率');