[~,Date]=xlsread('book','sheet1','a4:a122')<br>
Date=datenum(Date)<br>
Pa=xlsread('book ','sheet1','b4:b122');<br>
Pb=xlsread('book ','sheet1','c4:c122');<br>
Pc=xlsread('book','sheet1','d4:d122');<br>
[RetSeries1,RetIntervals1]=price2ret(Pa,Date)<br>
[RetSeries2,RetIntervals2]=price2ret(Pb,Date)<br>
[RetSeries3,RetIntervals3]=price2ret(Pc,Date)<br>
[Return]=[RetSeries1,RetSeries2,RetSeries3]<br>
ExpReturn=mean(Return)<br>
ExpCovariance=cov(Return)*250<br>
Numports=6 <br>
[PortRisk,PortReturn]=portopt(ExpReturn,ExpCovariance,Numports);<br>
plot(PortRisk,PortReturn,'ro-') <br>
title('均值-方差有效前沿以及各个资产风险与收益')<br>
xlabel('风险（标准差）')<br>
ylabel('期望收益率 ');