Peskarik
06-20-2008, 05:39 PM
Hello everyone,
I am learning about copulas and also do some MATLAB coding to get better understanding of how copulas work.
Recently I have started coding simple copula-GARCH models, that is I fit say AR(1)-GARCH(1,1)-normal models to univariate time series, and then I want to fit the copula (two-stage procedure).
What I have problem with is connecting these two estimation stages. After I have estimated AR-GARCH univariate models, what do I take from these models and put into log-likelihood estimation of the copula? Do I take residuals from AR-GARCH models, or do I use estimated parameters of these models to produce samples that I then use in copula estimation stage? :confused:
I read a few papers that use copula-GARCH models, but it is not clear from them how to estimate copula model. :( One paper stated that after AR-GARCH univariate model is estimated, I get parameters THETA(x), where x is the time series used in estimation. And then I should estimate F(x, THETA(x)), that is cdf. :confused:
I still do not get it. :o
Probably very simple and obvious thing, but I just do not get it.
Could you please help me understand? How do I do it in MATLAB or R?
THanks in advance!
/Sergey
I am learning about copulas and also do some MATLAB coding to get better understanding of how copulas work.
Recently I have started coding simple copula-GARCH models, that is I fit say AR(1)-GARCH(1,1)-normal models to univariate time series, and then I want to fit the copula (two-stage procedure).
What I have problem with is connecting these two estimation stages. After I have estimated AR-GARCH univariate models, what do I take from these models and put into log-likelihood estimation of the copula? Do I take residuals from AR-GARCH models, or do I use estimated parameters of these models to produce samples that I then use in copula estimation stage? :confused:
I read a few papers that use copula-GARCH models, but it is not clear from them how to estimate copula model. :( One paper stated that after AR-GARCH univariate model is estimated, I get parameters THETA(x), where x is the time series used in estimation. And then I should estimate F(x, THETA(x)), that is cdf. :confused:
I still do not get it. :o
Probably very simple and obvious thing, but I just do not get it.
Could you please help me understand? How do I do it in MATLAB or R?
THanks in advance!
/Sergey