Displaying 20 results from an estimated 500 matches similar to: "Monte carlo simulation in fGARCH"
2009 Mar 02
1
(no subject)
Greetings,
I am using fGarch package to estimate and simulate GARCH models. What I would like to do is to perform Monte Carlo simulation. Unfortunately I cannot figure how to modify the code to achieve this. I use the following code to run a single simulation:
spec=garchSpec(model=list(ar= 0.440270860, omega=0.000374365,alpha=0.475446583 , mu=0, beta=0))
sim<-garchSim(spec,
2010 Aug 15
2
fGarch: how to use garchFit() in loop?
Dear expeRts,
How can I specify the order p,q of a GARCH(p,q) model within a loop? Here's a minimal example showing that an "Formula and data units do not match"-error appears:
library(fGarch)
spec <- garchSpec(model = list(alpha = 0.1, beta = c(0.4, 0.4)))
data <- garchSim(spec, n = 100)
x <- list()
for(q in 1:3){
print(q)
x[q] <-
2011 Sep 28
1
fGarch - Fitting and APARCH-Modell with fixed delta
Hi there,
I'm trying to fit a GJR-GARCH Model using fGarch. I wanted to try that by
fitting an APARCH model with a fixed delta of 2 and a non-fixed gamma. So I
was simply trying to use:
spec <- garchFit(~aparch(1,1),data=garchSim(),delta=2)
coef(spec)
And sometimes, it's working like a charm and delta is indeed exactly 2 in
the resulting coefficient vector.
Frequently, though, the
2010 Jan 27
0
GARCH (1,1) negative volatility???
Dear all,
I am using GARCH (1,1) model to simulate volatility.
But seems that I am missing something about how it works in R.
The following code produces negative results, though vola cannot be.
What is wrong here?
library("fSeries")
library("fGarch")
spec = garchSpec(model = list(omega = 0.01, alpha = 0.13, beta = 0.86))
gat <- garchSim(spec, n = 10)
Thanks a lot!
2009 Mar 12
0
GARCH variance equation with dummy variables
I am estimating daily electricity prices using GARCH (1,1). What I would like to see is whether there is some kind of daily or seasonal effect in variance of the price series. For instance, variance of electricity prices might be different (higher) during weekdays as opposed to during weekend. Thus, I would like to include some dummy variables in variance equation -but I don't know how to
2006 May 08
3
GARCH SIMULATION
Hi All,
I,m trying to do a GARCH simulation in R 2.3.0 release
in Windows XP. I've seen garchsim function but that is
for garch (1,1) and ?garch gives an example for ARCH
simulation. Can anyone help me how can i extend the
help shown in ?garch to GARCH simulation? Please help
me in this regard.
Thanks,
Sumanta Basak.
2008 Aug 12
2
Maximum likelihood estimation
Hello,
I am struggling for some time now to estimate AR(1) process for commodity price time series. I did it in STATA but cannot get a result in R.
The equation I want to estimate is: p(t)=a+b*p(t-1)+error
Using STATA I get 0.92 for a, and 0.73 for b.
Code that I use in R is:
p<-matrix(data$p) # price at time t
lp<-cbind(1,data$lp) # price at time t-1
2008 Apr 01
1
garch prediction
Hello
I want to predict the future values of time series with Garch
When I specified my model like this:
library(fGarch)
ret <- diff(log(x))*100
fit = garchFit(~arma(1,0,0)+garch(1, 1), data =ret)
predict(fit, n.ahead = 10)
meanForecast meanError standardDeviation
1 0.01371299 0.03086350 0.03305819
2 0.01211893 0.03094519 0.03350248
2009 Feb 17
1
R crash after fGarch update
Hi folks!
After updating my packages my R seems to have completely crashed as will not
start up - even after I installed 2.8.1 from 2.8.0.
I get the following:
Fatal error: unable to restore saved data in .Rdata
Error in loadNamespeace(name): there is no package called fGarch
But I do have a package called fGarch.
After I hit ok, it crashes and exits. I cannot use any functionality at
all.
2011 Jan 31
0
Applying previously fitted fGarch model
Greetings,
Suppose I fit an fGarch model via garchFit function for a time series X.
I'm wondering is there any easy way to apply the fitted model to a different
time series Y to calculate conditional variances and standardized residuals?
Thanks.
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2009 Jun 30
1
garchFit in fGarch fitted values are all the same
Dear all-
Package /fGarch/ version 2100.78 in R version 2.8.1 (2008-12-22)
running on linux 2.6.22.9-91.fc7
In trying to fit garch models in above environment. I am getting
"reasonable" fitted coefficients, but the fitObject@fitted are all the
same. This is true even for the help page example:
library(fGarch)
R> X.timeSeries = as.timeSeries(msft.dat)
R> head(
+
2011 Nov 06
0
fGarch: garchFit and include.shape/shape parameters
Hello,
The function garchFit in the package fGarch allows for choosing a
conditional distribution, one of which is the t-distribution. The function
allows specification of the shape parameter of the distribution (equal to
the degrees of freedom for the t-distribution), for which the default is set
to 4. The function also includes an option "include.shape", which is "a
logical flag
2011 Mar 24
1
Problems with predict in fGarch
Hello. I am using fGarch to estimate the following model:
Call:
garchFit(formula = fmla, data = X[, i], trace = F)
Mean and Variance Equation:
data ~ arma(1, 1) + garch(1, 1)
Conditional Distribution:
norm
Coefficient(s):
mu ar1 ma1 omega alpha1 beta1
-0.94934 1.00000 -0.23211 54.06402 0.45709 0.61738
Std. Errors:
based on Hessian
Error Analysis:
2008 Dec 30
1
A mistake in garchFit()? {fGarch}
Hello,
I was using garchFit {fGarch} to fit some GARCH processes.
I noticed that the result contains "Log Likelihood" value (right above
"Description"), but when I use .. at fit$llh to retrieve Log Likelihood value,
the sign switched.
I am confused about which value I should choose to report...
Any help here?
Thanks a lot!
Ted
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2010 Jul 14
0
fGarch: garchFit() with fixed coefficents
hello everybody,
I would like to fit a model to a times series (testing set) for out of
sample predictions using garchFit(). I would like to keep the coefficients
of ARMA/GARCH model fixed (as found by fitting the model to my training
set). The arima fitting function has such an option for that (fixed=NULL)
but the garchFit() doesnt.
It is very important for me to keep the same coefficients
2013 Feb 17
0
forecast ARMA(1,1)/GARCH(1,1) using fGarch library
Hi, i am working in the forecast of the daily price crude .
The last prices of this data are the following:
100.60 101.47 100.20 100.06 98.68 101.28 101.05 102.13 101.70 98.27
101.00 100.50 100.03 102.23 102.68 103.32 102.67 102.23 102.14 101.25
101.11 99.90 98.53 96.76 96.12 96.54 96.30 95.92 95.92 93.45
93.71 96.42 93.99 93.76 95.24 95.63 95.95 95.83 95.65
2008 Sep 26
0
maximum likelihood
Hello,
I am trying to estimate parameters of mean reverting process with jumps given by: dp=k(mu-p)dt+sigma*dz+Jdq where dp represents change in log of price, k is reversion factor, mu is long run level of price, sigma is standard deviation, and dq equals one with probability lambda if jump occurs and 1-lambda otherwise. J is jump size with mean muj and standard deviation delta. Therefore, when
2009 Mar 24
0
Unit root
I am confused by obtaining different results when testing for unit root when using different packages. I have 2625 price entries for which I want to determine whether they exhibit unit root. First I test using adf.test from tseries package by running:
> adf.test(P, k=30)
Augmented Dickey-Fuller Test
data: P
Dickey-Fuller = -4.685, Lag order = 30, p-value = 0.01
alternative hypothesis:
2009 Apr 06
1
Problem with Extracting Fitted Values from fGarch package
Good day everyone,
I fitted a GARCH model to a time series and R estimated the model and provide me with the estimates. However, when I tried to extract the fitted values from the estimated model I got the following error message:
"Error in .local(object, ...) : object "fit" not found"
I used the following to extract the fitted values
fitted_TASI <- fitted(garchFit(~
2011 Jul 27
0
problems with predict in fGarch
Hello I am trying to use predict from an arma-Garch model (arma(2, 2) +
garch(1, 1)) and I am getting the following error:
Error en arima(x = object@data, order = c(max(u, 1), 0, max(v, 1)), init =
c(ar, :
non-stationary AR part from CSS
Does anybody know what can be the reason of this error? The model I have
estimated is the following:
Title:
GARCH Modelling
Call:
garchFit(formula =