各位大侠，看看下面的似然函数表示究竞哪里有问题啊。EVIEWS总是提醒“missing values in @logl series at current coefficents at observation 2”@LOGL LOGL
RES=SQR(DUR)
RES2=LOG(DUR)
SIG2=OMEGA(1)+ALPHA(1)*RES2(-1)+BETA(1)*SIG2(-1)
LOGL=LOG(GAMA(1)/RES)+GAMA(1)*LOG(@GAMMA(1+1/GAMA(1))*RES/EXP(SIG2))-(@GAMMA(1+1/GAMA(1))*RES/EXP(SIG2))^GAMA(1)

是哪一步程序出了问题