Displaying 20 results from an estimated 10000 matches similar to: "Implementing an ARMA filter"
2003 Aug 14
1
filter ARMA process
Hi
given an ARMA process and the AR and MA coefficients I need the residuals.
arima() calculates the residuals together with the best AR and MA
coefficients, but I need the coefficients to take known values.
In S-PLUS there is a function arima.filt(). Is there something similar in
R?
Thanks for any help,
Matthias Budinger
2004 Jul 04
1
Re: Seasonal ARMA model
> It might clarify your thinking to note that a seasonal ARIMA model
> is just an ``ordinary'' ARIMA model with some coefficients
> constrained to be 0 in an efficient way. E.g. a seasonal AR(1) s =
> 4 model is the same as an ordinary (nonseasonal) AR(4) model with
> coefficients theta_1, theta_2, and theta_3 constrained to be 0. You
> can get the same answer as from
2011 Jan 03
1
ARIMA simulation including a constant
Hi,
I have been looking at arima.sim to simulate the output from an ARMA model
fed with a normal and uncorrelated input series but I cannot find a way to
pass an intercept / constant into the model. In other words, the model input
in the function allows only for the AR and MA components but I need to pass
a constant.
Can anyone help?
Thanks
Paolo
[[alternative HTML version deleted]]
2008 Mar 21
1
tseries(arma) vs. stats(arima)
Hello,
The "arma" function in the "tseries" package allows estimation of models
with specific "ar" and "ma" lags with its "lag" argument.
For example: y[t] = a[0] + a[1]y[t-3] +b[1]e[t-2] + e[t] can be estimated
with the following specification : arma(y, lag=list(ar=3,ma=2)).
Is this possible with the "arima" function in the
2007 Oct 22
1
Newbie help: Data in an arma fit
I'd like to fit an ARMA(1,1) model to some data (Federal Reserve Bank
interest rates) that looks like:
...
30JUN2006, 5.05
03JUL2006, 5.25
04JUL2006, N <---- here!
05JUL2006, 5.25
...
One problem is that holidays have that "N" for their data. As a test, I
tried fitting ARMA(1,1) with and without the holidays deleted. In other
words, I fit the above data
2005 Mar 31
2
how to simulate a time series
Dear useRs,
I want to simulate a time series (stationary; the distribution of
values is skewed to the right; quite a few ARMA absolute standardized
residuals above 2 - about 8% of them). Is this the right way to do it?
#--------------------------------
load("rdtb") #the time series
> summary(rdtb)
Min. 1st Qu. Median Mean 3rd Qu. Max.
-1.11800 -0.65010 -0.09091
2004 Oct 25
1
output processing / ARMA order identification
Dear R users,
I need to fit an ARMA model. As far as I've seen, EACF (extended ACF)
is not available in R.
1. Let's say I fit a series of ARMA models in a loop. Given the
code/output included below, how do I pull 'Model' and 'Fit' (AIC)
from each summary() so that I can combine them into an array/data
frame to be sorted by AIC?
2. Apart from EACF, are you aware perhaps
2003 May 16
3
ARMA.predict?
Hi there,
Does anyone know how to predict ARMA? It doesn?t have either predict or forecast methods. I found couple of packages called fbasic and fseries at http://www.itp.phys.ethz.ch/econophysics/R/, which has ?arma.predict? in it, but it doesn?t seem to be working. Any help in this regard would be appreciated. Thanks in advance.
Regards
Skanda Kallur
"Prediction is very difficult,
2009 May 26
1
R for arma mdel with constraints on parameters
Hi,
i am learning R recently and find it very helpful in time series model.
In ARMA model, given (p,q) it can get the estimation of a[i] and b[j] easily with arima() function.
X[t] = a[1]X[t-1] + ... + a[p]X[t-p] + e[t] + b[1]e[t-1] + ... + b[q]e[t-q]
but in my recent data model, i met a problem. In the ARMA model, p and q are fixed, but there are some constraints in the parameters
2009 Oct 13
1
How to specify an ARMA(1, [1,4]) model?
Hi,
I'm trying to model an ARMA(1,[1,4]),
i.e. I want only lags 1 and 4 of the Moving Average part.
It's the '[1,4]' part that is giving me a problem.
I've tried different arma's and arima's in different packages, namely:
packages tseries, fArma, FinTS, timeSeries, TSA, Zelig, ds1, forecast
For example, with package FinTS:
> ( ARIMA(y, order=c(1,0,c(1,4))) )
2000 Nov 17
2
Simulation of Timeseries
Hello,
I try to simulate an ARMA-model using R, but I didn't find any function
to generate such timeseries.
In Splus there is the function arima.sim which generates AR-, MA- and
ARIMA-series. Is there any similar in R?
Best regards,
Frank Beimfohr
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read
2013 Feb 28
1
ARMA and AR in R
Hello,
I would like to compute ARMA and AR using arima-function in R.
My question is: If I have Null=zero values in my data, what should I do?
Remove ? or doesn't matter for ARIMA-models and I can estimate my
coefficients including zero values in data in arima-function in R ? What
is the better way? How to manage the data for ARIMA estimation?
Thank you.
[[alternative HTML version
2009 Jun 19
1
using garchFit() to fit ARMA+GARCH model with exogeneous variables
Hello -
Here's what I'm trying to do. I want to fit a time series y with
ARMA(1,1) + GARCH(1,1), there are also an exogeneous variable x which I
wish to include, so the whole equation looks like:
y_t - \phi y_{t-1} = \sigma_t \epsilon_t + \theta \sigma_{t-1}
\epsilon_{t-1} + c x_t where \epsilon_t are i.i.d. random
variables
\sigma_t^2 = omega + \alpha \sigma_{t-1}^2 + \beta
2012 Mar 01
2
Robust ARMA Fitting in R?
Hello, BODY { font-family:Arial, Helvetica,
sans-serif;font-size:12px; }
Does any one know if there are any functions/packages available in R
for robust fitting of ARMA time series models (e.g., similar to the
function arima.rob() in S-PLUS)?
Many thanks and kind regards,
Isabella
Isabella R. Ghement, Ph.D.
Ghement Statistical Consulting Company
301-7031 Blundell Road,
2011 Aug 30
2
ARMA show different result between eview and R
When I do ARMA(2,2) using one lag of LCPIH data
This is eview result
>
> *Dependent Variable: DLCPIH
> **Method: Least Squares
> **Date: 08/12/11 Time: 12:44
> **Sample (adjusted): 1970Q2 2010Q2
> **Included observations: 161 after adjustments
> **Convergence achieved after 14 iterations
> **MA Backcast: 1969Q4 1970Q1
> **
> **Variable Coefficient Std.
2011 Jul 01
1
How to fit ARMA model
Hello,
I am having some problems with fitting an ARMA model to my time series data
(randomly generated numbers). The thing is I have tried many packages
[tseries, fseries, FitARMA etc.] and all of them giving very different
results. I would appreciate if someone could post here what the best package
is for my purpose.
Also, after having done the fitting, I would like to check for the model's
2007 Mar 07
1
good procedure to estimate ARMA(p, q)?
Hi all,
I have some residuals from regression, and i suspect they have correlations
in them...
I am willing to cast the correlation into a ARMA(p, q) framework,
what's the best way to identify the most suitable p, and q, and fit ARMA(p,
q) model and then correct for the correlations in regression?
I know there are functions in R, I have used them before, but I just want to
see if I can do
1999 Nov 14
1
bug in arma.sim (PR#322)
Dear Sir,
I think I found a bug in the function arma.sim, which is defined in
the help page of the function filter:
arma.sim <- function(n, ar = NULL, ma = NULL, sigma = 1.0)
{
x <- ts(rnorm(n+100, 0, sigma^2), start = -99)
if(length(ma)) x <- filter(x, ma, sides=1)
if(length(ar)) x <- filter(x, ar, method="recursive")
as.ts(x[-(1:100)])
}
I am using R
2004 Jul 25
1
Multivariate ARMA Model
Hi R-Community,
so far I dealt with univariate processes and used the function "arima" to
estimate an ARMA(1,1)-model. For multivariate processes there are the
functions "estVARXar" and "estVARXls" from package "DSE". But how can I
estimate an VARMA(1,1)-model, or even better determine the orders and
estimate the parameters?
Much thanks in advance,
Hagen
2009 Apr 26
1
simulate arima model
I am new in R.
I can simulate Arma, using Arima.sim
However, I want to simulate an Arima Model. Say (1-B)Zt=5+(1-B)at. I do not
know how to deal with 5 in this model.
Can any one could help me?
Thank you very much!
Regards,
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