look at the underlying source code

Michael
i was doing what you told me and everything seems to go alright, until i
face with one problem.
I dont know how can i get access to the function ".C("sgarchsimC")"
I dont know exactly what is the so called .Primitive() and how can i get
into.
I started with following instructions:

getMethod("ugarchsim","uGARCHfit")
getAnywhere(.sgarchsim)
getAnywhere(.sgarchsim1)

getAnywhere(.C("sgarchsimC"))

? ?A single object matching ?.C? ?sgarchsimC? was found
? ?It was found in the following places
? ?package:base
? ?namespace:base
? ?with value

? ?function (.NAME, ..., NAOK = FALSE, DUP = TRUE, PACKAGE, ENCODING)
?.Primitive(".C")
? Warning message:
? ?In find(x, numeric = TRUE) :
? elements of 'what' after the first will be ignored

i feel that i'm pretty near.
Do you have any idea??


2012/5/19 jaimie villanueva <jaimie.villanueva at gmail.com>

thank's a lot Michael.
Is exactly what i was looking for.

regards
Jamie

2012/5/19 R. Michael Weylandt <michael.weylandt at gmail.com>

Unfortunately the task is slightly harder here -- ugarchsim calls a
network of S4 code that is a little hard to trace....

You can get started by typing

getMethod("ugarchsim", "uGARCHfit")

to see the first step which calls a variety of functions with names like

.sgarchsim

You'll have to read a line of code here that uses switch so it's a
little harder to follow if you've never used that construct before
than method dispatch or if/then might be.

It looks like these are not exported so you'll have to use

getAnywhere(.sgarchsim)

to start following those. It looks like that in turn calls .sgarchsim1
or .sgarchsim2 which are the end of the line and should help you out.

Hope this helps,
Michael

On Fri, May 18, 2012 at 2:16 PM, Rui Barradas <ruipbarradas at sapo.pt>
wrote:

Hello,

There are two simple ways,

1. Type ?the function name without parenthesis at an R prompt;
2. Download the source from CRAN or R-Forge, R is open source.

Hope this helps,

Rui Barradas

jaimie villanueva wrote

hi

someone can show me how can i get the source code of a function. Is a
S4
class or Method. (I'm not an expert in R environment)
Exactly, Function "ugarchsim" from library (rugarch).
I need to know (in detailed ) how the variance and ?mean ecuation of a
arma/garch process are calculated.
With other packages like "fGarch" i used to invoked the function debug
()
and allows me to step into the functions but with ugarchsim i can't
use
it.

any suggestions are well received

thanks

Jamie

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