datalog_ret(keep=date);

setstoindiv.a1a0001;

where1995<=year(date)<=2000;

%macro a(x);

data a(keep=dater_1);

setstoindiv.a&x;

where1995<=year(date)<=2000;

r_1=log(clpr)-log(lag(clpr));

clpr_1=clpr*(1+divrat+rigrat+reisvol/lag(shrout))-rigrat-reispr*reisvol/lag(shrout)+divamt;

if clpr_1=. thenclpr_1=clpr;

r_2=log(clpr_1)-log(lag(clpr_1));

if exdt^=. thenr_1=0;

r_1=r_1+r_2;

if r_1=. then r_1=0;

else r_1=r_1;

datalog_ret(rename=(r_1=r&x));

merge log_ret a;

by date;

rr&x=r&x**2;

%mend a;

%a(1a0001);

%a(600652);

run;

这个语句产生了变量R1A0001和r600652提示未初始化，但是程序运行有观测值，这是什么原因呢？？