Initial value for mvgarch model

Discussions of ARCH, GARCH, and related models

Initial value for mvgarch model

Postby yli725 » Tue Mar 19, 2013 10:30 pm

Dear Tom,
I have some Convergence problem when I estimate a multivariate GARCH model, so I want to specify the initial value. I saw there is a method option "evaluate", but I do not know how to use that with initial.

First, I estimate a model use the code
Code: Select all
garch(p=1,q=1,model=var4,asymmetirc,distrib=t,mv=bekk,method=bhhh,iters=500,pmethod=simplex,piters=50,hmatrices=hh,rvectors=rd) / y1 y2 y3

Then ???
Code: Select all
garch(p=1,q=1,model=var4,asymmetirc,distrib=t,mv=bekk,method=evaluate,initial=??? iters=500,pmethod=simplex,piters=50,hmatrices=hh,rvectors=rd) / y1 y2 y3


I am a new user of Rats, thank you for your kindly help!
yli725
 
Posts: 5
Joined: Mon Mar 11, 2013 4:39 pm

Re: Initial value for mvgarch model

Postby TomDoan » Wed Mar 20, 2013 12:15 pm

yli725 wrote:Dear Tom,
I have some Convergence problem when I estimate a multivariate GARCH model, so I want to specify the initial value. I saw there is a method option "evaluate", but I do not know how to use that with initial.

First, I estimate a model use the code
Code: Select all
garch(p=1,q=1,model=var4,asymmetirc,distrib=t,mv=bekk,method=bhhh,iters=500,pmethod=simplex,piters=50,hmatrices=hh,rvectors=rd) / y1 y2 y3

Then ???
Code: Select all
garch(p=1,q=1,model=var4,asymmetirc,distrib=t,mv=bekk,method=evaluate,initial=??? iters=500,pmethod=simplex,piters=50,hmatrices=hh,rvectors=rd) / y1 y2 y3


I am a new user of Rats, thank you for your kindly help!


Changing the guess values is rarely a help. I would suggest reducing the number of simplex iterations (10-15 is usually enough) and switching from BHHH to BFGS.
TomDoan
 
Posts: 2720
Joined: Wed Nov 01, 2006 5:36 pm


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