# Re: [R] garch in tseries

From: Spencer Graves <spencer.graves_at_pdf.com>
Date: Thu 04 May 2006 - 02:46:41 EST

Dear Erin:

While I misread your question earlier, it looks to me like you could get what you want by first subtracting some number close to the mean or median, then using garchFit{fSeries}. If you can't get that to work, could you please notify both Diethelm Wuertz and me?

```	  Best Wishes,
spencer graves
###############
The documentation for my currently installed version of
```
garchFit{fSeries} indicates that the default include.mean = TRUE.

How do you know "it didn't work"? With the default include.mean = TRUE, the following took just under a minute on my IBM T-30 notebook:

library(fSeries)
data(sp500dge)
# Vector of Compounded Returns:
x <- diff(sp500dge[,1])
# Vector of Percentage Compounded Returns: X = 100*x
fit = garchFit(~arma(0,1), ~garch(1,1), series = X)

Moreover, print(fit) included a parameter 'mu' whose names suggests that it is a mean that might not bre estimated if 'include.mean = FALSE'.

However, when I tried it, it went into an apparent infinite loop, which I killed after ~15-20 minutes:

fit0 = garchFit(~arma(0,1), ~garch(1,1), series = X,

include.mean=FALSE)

I got a similar potentially infinite loop from the following:

fit2 = garchFit(~arma(0,1), ~garch(1,1), series = X+100)

However, the following converged and estimated mu at 0.1000, as simulated:

fit.1 = garchFit(~arma(0,1), ~garch(1,1), series = X+0.1)

Conclusion: The code seems to work as documented, sometimes. Unfortunately, it appears to have a disturbing affinity for an apparent infinite loop, and I don't have the time now to diagnose it further.

```	  hope this helps.
spencer graves

```

Erin Hodgess wrote:

> Hello again!
>
> Is there a way to include a mean in the garch function in the
>
> I tried include.mean=T in the function statement but it didn't work
>
>
> R Version 2.2.1 Windows
> Sincerely,
> Erin
> mailto: hodgess@gator.uhd.edu
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help

R-help@stat.math.ethz.ch mailing list