Displaying 20 results from an estimated 4000 matches similar to: "estimating an ARIMA model with constraints"
2003 Jan 09
2
using arima() function
HI, there,
When i use R, i tried to use function arima(), it complains:
Error: couldn't find function "arima"
But when I type "help.search("arima") ",
I got arima() poped up..
arima(ts) ARIMA Modelling of Time Series
arima.sim(ts) Simulate from an ARIMA Model
arima0(ts) ARIMA Modelling of Time Series -- Preliminary
2000 Dec 30
3
ARIMA
Thanks,
Can't find an ARIMA in base, dse1/2 or tseries, only references to. What
package is it in?
Thanks again!
Best regards,
/fb
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2004 Aug 29
1
predict(arima)
Dear All,
R 1.9.1, Windows
When copying and pasting a few lines from the 'predict.Arima' help, I
get an error message:
> data(lh)
> predict(arima(lh, order = c(3,0,0)), n.ahead = 12)
Error in eval(expr, envir, enclos) : Object "xreg" not found
On the other hand, the following is OK:
> data(lh)
> predict(arima0(lh, order = c(3,0,0)), n.ahead = 12)
$pred
Time
2005 Jul 08
1
help with ARIMA and predict
I'm trying to do the following out of sample
regression with autoregressive terms and additional x
variables:
y(t+1)=const+B(L)*y(t)+C(1)*x_1(t)...+C(K)*x_K(t)
where:
B(L) = lag polynom. for AR terms
C(1..K) = are the coeffs. on K exogenous variables
that have only 1 lag
Question 1:
-----------
Suppose I use arima to fit the model:
2001 Apr 24
1
ARIMA and GARCH
Hello,
I would like to study time series with ARIMA and GARCH models.
I installed R-Plus and its libraries but when I try to execute the function
arima0, It answers that the function does not exist.
Could you help me or give me references of papers dealing with arima and garch
in R-Plus?
Thanks
Beno?t,
___________________________________
Mr. Beno?t LACHERON
Rue de l'industrie, 44,
1040
2009 Apr 22
1
arima
Hi,
I have a suggestion for the fonction arima and arima0. I think you
should not call the constant an intercept because it creates confusion.
It is not really an intercept but a mean. For an AR(1) the intercept mu
should be defined as:
X(t)=mu + phi X(t-1) + e(t)
What you call intercept mu is rather defined as
(X(t)-mu) = phi (X(t-1)-mu)) + e(t)
which is not a common way to define an
2003 Apr 30
2
Bug in arima?
I'm using the fixed argument in arima. Shouldn't ar4, ar5, and ar6
display as zero in the output?
Call:
arima(x = window(log(hhprice), start = c(1990, 1), end = c(2003, 3)),
order = c(7,
1, 0), xreg = window(ts.union(exa1 = lag(exa, -1), exa12 = lag(exa,
-12), exb1 = lag(exb, -1), exc1 = lag(exc, -1), exc12 = lag(exc,
-12)), start = c(1990, 1), end = c(2003, 3)),
2004 Jun 17
1
Error with arima()
Could someone please give a brief explanation, or pointer to an explanation,
of the following error:
> arima(ts.growth, order = c(1,0,0),include.mean=T)
Error in arima(ts.growth, order = c(1, 0, 0), include.mean = T) :
non-stationary AR part from CSS
and why it does not arise with
> arima0(ts.growth, order = c(1,0,0))
Many thanks
____________________________
Dr. Daniel P. Bebber
2006 Oct 19
1
predict.Arima question
Hi,
I am trying to forecast a model using predict.Arima
I found arima model for a data set: x={x1,x2,x3,...,x(t)}
arima_model = arima(x,order=c(1,0,1))
I am forecasting the next N lags using predict:
arima_pred = predict(arima_model,n.ahead = N, se.fit=T)
If I have one more point in my series, let's say x(t+1). I do not want to
recalibrate themodel, I just want to forecast the next N-1
2001 Dec 16
3
Arima
I did a regression with ARMA errors using arima0 with
ari<-arima0(y,order=c(2,0,2),xreg=reg1,delta=-1)
or
ari<-arima0(y,order=c(2,0,2),xreg=reg1)
where reg1 is the matrix of the regressors and when I see diag(ari$var.coef)
I get negative terms. Do you know what this mean ?
I try to change transform.pars to 0 or 1 but this crash R on Windows.
Is it possible to test the significativity
2008 May 08
1
ARIMA, AR, STEP
Here is my problem:
Autoregressive models are very interesting in forecasting consumptions (eg water, gas etc).
Generally time series of this type have a long history with relatively simple patterns and can be useful to add external regressors for calendar events (holydays, vacations etc).
arima() is a very powerful function but kalman filter is very slow (and I foun difficulties of estimation)
2004 Mar 22
1
problem with seasonal arima
hallo to all
I've to calculate an arima model and I need only the
first and 365 th parameter and also the sar1 and the
intercept, so I'm traing with:
arima(X,order=c(365,0,0),seasonal=list(order=c(1,0,0),..),fixed=c(NA,rep(0,363),NA,NA,NA),transform.pars=F)
but the error answer is:
Error in polyroot(z) : polynomial degree too high (49
max)
also there are problems in allocating memory
2003 Jul 10
2
please help on frag polynoms
hi there,
can anyone help me on the topic of frag polynoms?
i just heard of a friend of mine, that i could build in a functioon called
fragpoly (he was talking of such a function in the 'stata' language) in order
to improve my process of finding an optimal linear model.
instead of trying a vast amount of transformed inputdata to find the best
fit and then step backwards down to e.g.
2006 Nov 25
2
predict and arima
Hi all,
Forecasting from an arima model is easy with predict.
But I can't manage to backcast : invent data from the model before the
begining of the sample.
The theory is easy : take your parameters, reverse your data, forecast, and
then reverse the forecast
I've tried to adapt the predict function to do that (i'm not sure that the
statistical procedure is fine (with the residuals),
2000 Aug 05
1
new arima source code
Greetings:
I was looking for the source code for the new arima procedure. I checked
the floppies directory and downloaded R-devel-2.tar.gz but this
only included the old starma.f. Is the new code available yet?
Thanks,
George
gwtim at 2xtreme.net
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2000 Apr 09
2
(1) arima.mle implementation; (2) r-newbie forum
Has arima.mle (MASS, Ch.15, p.464) been implemented in R?
[A search through contributed packages and R-FAQ suggests not,
and I don't think function 'lme' from package 'nlme' would
accomplish the same sort of thing, although it permits
correlated errors. A search of the CRAN site shows this
question has been asked some time ago, and it was suggested
that Paul Gilbert's
2002 Mar 08
4
ARMA and ARIMA modeling
I'd like to play with ARIMA models of stock prices, but I am a complete novice.
Could some kind soul explain the relationship among packages "ts", "tseries",
"dse", "dse2", and "fracdiff"? Are they 'competing' products or does one
depend on another? Where would be the best place for a novice to begin?
Thanks for any advice.
PS. I
2008 Mar 07
5
Puzzling coefficients for linear fitting to polynom
Hi,
I can not comprehend the linear fitting results of polynoms. For
example, given the following data (representing y = x^2):
> x <- 1:3
> y <- c(1, 4, 9)
performing a linear fit
> f <- lm(y ~ poly(x, 2))
gives weird coefficients:
> coefficients(f)
(Intercept) poly(x, 2)1 poly(x, 2)2
4.6666667 5.6568542 0.8164966
However the fitted() result makes sense:
>
2003 Mar 04
3
linear model with arma errors
Dear all,
I'm looking for how can I estimate a linear model with ar(ma) errors :
y(t)=a*X(t)+e(t) with
P(B)e(t)=Q(B)u(t)
where u is a white noise and P, Q are some polynomes.
Could you help me ?
Gr?gory Benmenzer