Displaying 20 results from an estimated 2000 matches similar to: "arima function"
2009 Mar 06
0
modifying a built in function from the stats package (fixing arima) (CONCLUSIONS)
Thanks a lot to everybody that helped me out with this.
Conclusions:
(1)
In order to edit arima in R:
>fix(arima)
or alternatively:
>arima<-edit(arima)
(2)
This is not contained in the "Introduction to R" manual.
(3)
A "productive" fix of arima is attached (arma coefficients printed out and
error catched so that it doesn't halt parent loops to search for
2007 Apr 17
2
background color
hi,
I want to add different colors on the background of a classical plot. Each color is associated to an interval of the x axis.
example: the background is red on the interval [1,10], blue on [11,20].
I try the rect function but it isn't appropriate for the background.
Can any one can help me please?
best regards.
---------------------------------
[[alternative
2009 Mar 01
0
Variable scope.
I have a question on scope/reference/value type of variables with 'R'.
The issue cam up first when I look at the arima code.
I see code like:
myupARIMA <- function(mod, phi, theta) {
. . . .
mod
}
Then
armafn <- function(p, trans) {
. . . .
Z <- upARIMA(mod, trarma[[1]], trarma[[2]])
. . . .
res <- .Call(R_ARIMA_Like, x,
2007 Jan 16
1
SARIMA problem
Hi,
I have a problem with the ARIMA function, occuring when I set the parameter per (the period of SARIMA model) to a high value (see the exemple bellow). It seems that when per is high it takes a too large amount of memory to calculate the model and I have a memory storage error. But I don't really understand why it takes more memory when per is high, as there is the same number of
2017 Mar 20
0
outer not applying a constant function
>>>>> Gebhardt, Albrecht <Albrecht.Gebhardt at aau.at>
>>>>> on Sun, 19 Mar 2017 09:14:56 +0000 writes:
> Hi,
> the function outer can not apply a constant function as in the last line of the following example:
>> xg <- 1:4
>> yg <- 1:4
>> fxyg <- outer(xg, yg, function(x,y) x*y)
>> fconstg
2009 Sep 29
0
Incoherence between arima.sim and auto.arima
Hello,
I have a question about function arima.sim
I tried to somulate a AR(1) process, with no innovation, no error term.
I used this code:
library(forecast)
e=rnorm(100,mean=0,sd=0)
series=arima.sim(model=list(ar=0.75),n=100,innov=e)+20
Then I tried to applicate ti this series auto.arima function:
mod1<-auto.arima(series,stepwise=FALSE,trace=TRUE,ic='aicc')
The best model returned
2017 Mar 19
2
outer not applying a constant function
Hi,
the function outer can not apply a constant function as in the last line of the following example:
> xg <- 1:4
> yg <- 1:4
> fxyg <- outer(xg, yg, function(x,y) x*y)
> fconstg <- outer(xg, yg, function(x,y) 1.0)
Error in outer(xg, yg, function(x, y) 1) :
dims [product 16] do not match the length of object [1]
Of course there are simpler ways to construct a constant
2017 Mar 20
1
outer not applying a constant function
> Or is this a bad idea?
I don't like the proposal. I have seen code like the following (in
fact, I have written such code, where I had forgotten a function was
not vectorized) where the error would have been discovered much later
if outer() didn't catch it.
> outer(1:3, 11:13, sum)
Error in outer(1:3, 11:13, sum) :
dims [product 9] do not match the length of object [1]
2009 Mar 08
0
ARIMA second order differencing problem
Hi,
I have been using this site (
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm) to help me with some
ARIMA modelling in R.
Unfortunately the methods mentioned do not appear to work with second order
differencing; arima(*, 2, *).
I have used some dummy data to illustrate my point.
When I use the xreg=... method, the estimate of intercept is *way* off. This
can be seen by the high s.e but I
2008 Sep 16
0
Warning messages after auto.arima
Dear R-helpers.
Would appreciate if someone can explain the warning messages below, after
auto.arima. I couldn't find any clue in the archived help.
Also, how do I retrieve the AICs of each tried model in auto.arima? The
purposes are (1) to output to a text file, and (2) to find the 2nd best
model by finding 2nd lowest AIC instead of eyeballing thru the value at the
console
2018 May 22
3
Cannot delete folder
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Mon, 21 May 2018, Yves Goergen wrote:
>> May 21 10:36:14 mond2 dovecot: imap(yg@****.de): Debug: Namespace :
>> /var/mail/virtual/****.de/yg/.Test doesn't exist yet, using default
>> permissions
>> May 21 10:36:14 mond2 dovecot: imap(yg@****.de): Debug: Namespace : Using
>> permissions from
2009 Oct 22
1
arima crashes too
Another pathological test.
arima does not crash for that series that crashes arma:
arima(c(2.01, 2.22, 2.09, 2.17, 2.42), order=c(1,0,0))
However, arima crashes for this:
arima(c(1.71, 1.78, 1.95, 1.59, 2.13), order=c(1,0,0))
arima seems pretty consistent in its crashing behaviour, since crashing for
one series means crashing for all affine series:
lets.crash.arima <- c(71, 78, 95, 59,
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
2013 Jul 18
0
Difference between arima(1, 1, 1) for y and arima(1, 0, 1) for diff(y)
Dear all,
When I run an arima(1,1,1) on an I(1) variable, e.g. y, I get different
estimates to when I first difference the variable myself, e.g y2<-diff(y),
and then run arima(1,0,1) on y2. Shouldn't these two approaches give the
same output?
Any help will be much appreciated.
george
--
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2010 Aug 19
1
How to include trend (drift term) in arima.sim
I have been trying to simulate from a time series with trend but I don't see
how to include the trend in the arima.sim() call. The following code
illustrates the problem:
# Begin demonstration program
x <- c(0.168766559, 0.186874000, 0.156710548, 0.151809531, 0.144638812,
0.142106888, 0.140961714, 0.134054659, 0.138722419, 0.134037018,
0.122829846, 0.120188714,
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
2003 Apr 07
1
filtering ts with arima
Hi,
I have the following code from Splus that I'd like to migrate to R. So far,
the only problem is the arima.filt function. This function allows me to
filter an existing time-series through a previously estimated arima model,
and obtain the residuals for further use. Here's the Splus code:
# x is the estimation time series, new.infl is a timeseries that contains
new information
# a.mle
2012 May 18
0
Forecast package, auto.arima() convergence problem, and AIC/BIC extraction
Hi all,
First:
I have a small line of code I'm applying to a variable which will be
placed in a matrix table for latex output of accuracy measures:
acc.aarima <- signif(accuracy(forecast(auto.arima(tix_ts,
stepwise=FALSE), h=365)), digits=3).
The time series referred to is univariate (daily counts from 12-10-2010
until 5-8-2010 (so not 2 full periods of data)), and I'm working on
2012 Mar 05
0
auto.arima and intervention analysis
Hello,
I'm currently using auto.arima to verify the order of my arima model. I
would like to use the model to conduct an intervention analysis. The problem
is that, when I include a step function in auto.arima, by including a binary
variable in "xreg", the arima order that auto.arima gives is different from
when I don't include it. From my understanding, the
2009 Jul 21
0
Specifying initial values for arima.sim
Hi Everyone,
I'm having a problem with arima.sim. Namely specifying inital values
for the series.
If I generate a random walk
> vs = rnorm(100,0,1)
> xs = cumsum(vs)
and fit an ARIMA(1,0,0) to it
> xarima = arima(xs,order=c(1,0,0))
> xarima
Call:
arima(x = xs, order = c(1, 0, 0))
Coefficients:
ar1 intercept
0.9895 8.6341
s.e. 0.0106 6.1869
I should