Displaying 20 results from an estimated 7000 matches similar to: "Fitting an ARIMA model to a time series"
2012 Mar 03
1
Sliding Window in R (solved)
Dear all,
you can find below my solution for sliding a window. Please find below the code for the two alternatives and the benchmarks.
install.packages('caTools')
require(caTools)
do_sliding_for_a_window_duty_cycle <- function(DataToAnalyse, windowSize) {
data<-DataToAnalyse
out <- numeric()
elements<- numeric()
if (length(data[,1]) >= windowSize){
for
2012 Apr 26
1
Using the R predict function to forecast a model fit with auto.arima function
Hello R users,
Hope everyone is doing great.
I have a dataset that is in .csv format and consists of two columns: one
named Period (which contains dates in the format yyyy_mm) and goes from
1995_10 to 2007_09 and the second column named pcumsdry which is a
volumetric measure and has been formatted as numeric without any commas or
decimals.
I imported the dataset as pauldataset and made use of
2004 May 24
0
Seasonal ARIMA question - stat package (formerly ts)
To whom it may concern:
I am trying to better understand the functionality of 'R' when making
arima predictions to avoid any "Black Box" disadvantages.
I'm fitting a seasonal arima model using the following command (having
already loaded 'stat' package).
arimaSeason <-
arima(Data,order=c(1,0,1),seasonal=list(order=c(1,0,1),period=12))
I can then generate
2002 Nov 18
1
Prediction from arima() object (library ts) (PR#2305)
Full_Name: Allan McRae
Version: 1.6.0
OS: Win 2000 P
Submission from: (NULL) (129.215.190.229)
When using predict.Arima in library ts(), it appears differencing is only
accounted for in the first step of prediction and so any trend is not apparent
in the predictions. The example shows the difference between the predictions of
an arima(1,1,1) model and the backtransformed predictions of an
2007 Jul 02
0
ARIMA prediction
Hi
This is my first post to this group, so apologies in advance if I get it wrong.
I would like to know how the prediction for arima models works in R. I
have a time series to which I fit an arima model, of varying AR and MA
orders. I then use the predict function to project it forward. I have
also written my own function to perform the prediction, but it gives
different answers to Arima.predict
2013 Sep 09
1
Fitting Arima Models and Forecasting Using Daily Historical Data
Hello everyone,
I was trying to fit an arima model to a daily historical data, but, for
some reason, havent been able to.
I basically have 212 observations (from 12/1/2012 to 06/30/2013) containing
the number of transits for a particular vessel.
The following messages are produced by R:
dailytrans.fit<-arima(dailytrans$transits, order=c(0,1,2),
seasonal=list(order=c(0,1,2), period=365),
2009 Nov 16
1
ARMAX model fitting with arima
I am trying to understand how to fit an ARMAX model with the arima
function from the stats package. I tried the simple data below, where
the time series (vector x) is generated by filtering a step function
(vector u, the exogenous signal) through a lowpass filter with AR
coefficient equal to 0.8. The input gain is 0.3 and there is a 0.01
normal white noise added to the output:
x <- u
2010 Sep 11
0
outputting arima models
sseq <- c(1, seq(5, 120, by = 5))
for(i in 1:length(sseq)){
assign(paste("arima", i, sep=""), arima0(data.ts[sseq[i]:(sseq[i]+115)],
order=c(1,1,1)))
}
pred1 = predict(arima1, n.ahead = 5, se.fit = TRUE)$pred
how do I traverse the arima models so I repeat the above prediction
procedure(bold) on all arima models. Also, how do i automatically create
one huge vector of the
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
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
2011 Dec 12
1
Question about fitting seasonal ARIMA in R?
Hi all,
I just couldn't find a R function which can fit multiple seasonal
patters... i.e. in the following code:
*arima(x = data, order = c(p, d, q), seasonal = list(order = c(P, D, Q),
period = S), ...
***
*
there can be only one "period", am I right?
What if the data seem to have three different seasonality cycles, 5, 12, 21?
Thanks a lot!
*
[[alternative HTML version
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
2012 Sep 28
0
Questions about the functions ar.ols and auto.arima when fitting an AR model
Hi,
I am trying to fit an AR model, maximum order =4, order selection
criterion is aic. I wonder why these two give different results:
m1<-ar.ols(x, aic=TRUE, method="ols", order.max=4)
m1<-auto.arima(x,d=0, D=0, max.p=4, max.P=0, max.q=0, max.Q=0, ic="aic")
Could they both use the function predict to do forecasting? Is there any
function that works better?
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,
2005 Oct 04
2
Need help on ARIMA (time series analysis)
Hi,
I am so novice in using R. I have some problems in my R script below
which fits time series data and predict it one-step ahead. Here is a
brief explanation on what I try to achieve
Th16k is time series data (500 data points). The size of window for
fitting and predicting is 50 (data points). As you can easily discover
from my code, (fixed) window is moving/sliding to get next one-step
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,
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
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
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