我在eviews上编了一个garch(1,1)的程序,但估计的参数都不显著,而用eviews界面的操作的结果却是显著的。我怀疑是付初值有问题,但试了好多总是调试不好。望牛人指点一下。程序如下:
series y=sz
sample s0 1 1762
sample s1 2 1762
smpl s0
equation eq1.ls y c
series u=(resid)^2
smpl s1
equation eq2.ls u c u(-1)
coef(1) mu
mu(1)=eq1.c(1)
coef(1) omega
omega(1)=(eq2.c(1))^.5
coef(2) alpha
alpha(1)=(eq2.c(2))^.5
alpha(2)=0.1
!mlog2pi=2*log(2*@acos(-1))
smpl s0
series var1=@var(y)
series sqres=(y-mu(1))^2
logl lll
lll.append @logl logl
lll.append sqres=(y-mu(1))^2
lll.append var1=omega(1)+alpha(1)*sqres(-1)+alpha(2)*var1(-1)
lll.append z=sqres/var1
lll.append logl=-0.5*(!mlog2pi+log(var1)+log(z))
smpl s1
lll.ml(showopts, m=100,c=1e-5)
show lll.output


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