Displaying 20 results from an estimated 200 matches similar to: "forecasting error?"
2009 Jan 21
1
forecasting issue
Hello everybody!
I have a problem when I try to perform a forecast of an ARIMA model
produced by an auto.arima function. Here is what I'm doing:
c<-auto.arima(fil[[1]],start.p=0,start.q=0,start.P=0,start.Q=0,stepwise=TRUE,stationary=FALSE,trace=TRUE)
# fil[[1]] is time series of monthly data
ARIMA(0,0,0)(0,1,0)[12] with drift : 1725.272
ARIMA(0,0,0)(0,1,0)[12] with drift
2010 May 04
1
How to make predictions with the predict() method on an arimax object using arimax() from TSA library
Hi R Users,
I'm fairly new to R (about 3 months use thus far.)
I wanting to use the arimax function from the TSA library to incorporate some exogenous inputs into the basic underllying arima model.Then with that newly model of type arimax, I would like to make a prediction.
To avoid being bogged down with issues specific to my own work, I would like to refer to readers to the example
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:
2023 Jan 05
1
R 'arima' discrepancies
Rob J Hyndman gives great explanation here
(https://robjhyndman.com/hyndsight/estimation/) for reasons why results
from R's arima may differ from other softwares.
@iacobus, to cite one, 'Major discrepancies between R and Stata for
ARIMA'
(https://stackoverflow.com/questions/22443395/major-discrepancies-between-r-and-stata-for-arima),
assign the, sometimes, big diferences from R
2017 Jun 20
1
How to write an estimated seasonal ARIMA model from R output?
I'm trying to use the following command.
arima (x, order = c(p,d,q), seasonal =list(order=c(P,D,Q), period=s)
How can I write an estimated seasonal ARIMA model from the outputs. To be specifically, which sign to use? I know R uses a different signs from S plus.
Is it correct that the model is:
(1-ar1*B-ar2*B^2-...)(1-sar1*B^s-sar2*B^2s-....)(1-B)^d(1-B^s)^D
2003 Dec 18
1
Help with predict.Arima with external regressor values [Repalced]
Hi all there
I am enjoying R since 2 weeks and I come to my first deadlock, il am trying
to use predict.Arima in the ts package.
I get a "Error in cbind(...) : cannot create a matrix from these types"
-- Start R session -----------------------------------------------------
> fitdiv <- arima(data, c(2, 0, 3), xreg = y ) ; print(fitdiv)
Call:
arima(x = data, order = c(2, 0, 3),
2011 Dec 17
0
auto.arima from the Forecast package
Hi,
I've got a little problem using auto.arima.
I run the following command
auto.arima(drivers,ic="aic",d=1,D=1,max.order=10,max.p=5,max.q=5,max.P=5,max.Q=5,stepwise=FALSE,allowdrift=FALSE)
and I get the following output :
Series: drivers
ARIMA(0,1,1)(5,1,1)[12]
Coefficients:
ma1 sar1 sar2 sar3 sar4 sar5 sma1
-0.6421
2009 Feb 08
0
Initial values of the parameters of a garch-Model
Dear all,
I'm using R 2.8.1 under Windows Vista on a dual core 2,4 GhZ with 4 GB
of RAM.
I'm trying to reproduce a result out of "Analysis of Financial Time
Series" by Ruey Tsay.
In R I'm using the fGarch library.
After fitting a ar(3)-garch(1,1)-model
> model<-garchFit(~arma(3,0)+garch(1,1), analyse)
I'm saving the results via
> result<-model
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
2007 Mar 02
0
R: ARIMA forecasting
Dear all,
I just have a short question regarding the forecasting of ARIMA models with
external regressors.
I tried to program a ARX(1) model
arx.mod <- arima(reihe.lern, order = c(1, 0, 0), seasonal =
list(order = c(0, 0, 0), period = 52), xreg = lern.design, include.mean =
TRUE)
for which I need to estimate the next (105th) value. Xreg=lern.design is -
at this time - 104 rows long. I
2003 Apr 17
2
Testing for Stationarity of time series
Hi there,
Does anyone know if R has a function for testing whether a time series is
stationary??
Thanks in advance,
Wayne
Dr Wayne R. Jones
Statistician / Research Analyst
KSS Group plc
St James's Buildings
79 Oxford Street
Manchester M1 6SS
Tel: +44(0)161 609 4084
Mob: +44(0)7810 523 713
KSS Ltd
A division of Knowledge Support Systems Group plc
Seventh Floor St James's
2004 Apr 02
1
R on Tru64 OSF 5.1
Has anyone achieved a current successful build of R
1.8 or 1.9 or earlier for HPUX Tru 64 OSF 5.1?
There is no binary version of R for HPUX Tru 64 OSF
5.1. The R admin manual mentions that the native make
fails on "Alpha/OSF (aka Tru 64)" and gnu make must be
used instead. There are problems reported with
building R versions around 1.4 from 2002 on R-devel,
some of which were fixed with
2009 Jan 18
1
auto.arima forecasting issue
Hello everybody!
I'm having this problem with the auto.arima function that i've not been
able to solve. I use this function on time series that contains NA values,
but every time that the resulting model contains drift I can't perform a
forecasting (using forecast.Arima function). The printed error (when I try
to forecast the resulting model) claims a dimension mismatch
2013 Mar 22
0
predict.Arima error "'xreg' and 'newxreg' have different numbers of columns"
Hello all,
I use arima to fit the model with
fit <- arima(y, order = c(1,0,1), xreg = list.indep, include.mean = TRUE)
and would like to use predict() to forecast:
chn.forecast <- rep(0,times=num.record)
chn.forecast[1] <- y[1]
for (j in 2:num.record){
indep <- c(aa=chn.forecast[j-1], list.indep[j,2:num.indep]) # this is the newxreg in the
2009 Feb 17
0
What's the predict procedure of ARIMA in R?
Hello,guys:
Recently, I am working on a seasonal ARIMA model. And I met some problem in the forecasting.
Now I just want to know that How does R perform the predict procedure(the predict formula, the initial setting of errors,etc.)?
I run the following commands and get the original code of the "predict" command, but I can't read it.
Can anybody explain it to me?
Thanks!
saji from
2010 Mar 31
1
predict.Arima: warnings from xreg magic
When I run predict.Arima in my code, I get warnings like:
Warning message:
In cbind(intercept = rep(1, n), xreg) :
number of rows of result is not a multiple of vector length (arg 1)
I think this is because I'm not running predict.Arima in the same
environment that I did the fit, so the data object used in the fit is no
longer present. Looking at the predict.Arima source,
2008 Jul 08
0
forecast & xreg
Dear all,
I am fitting an arimax (arima with some extra explanatory variables)
model to a time series. Say, I have a Y (dependent variable) and an X
(explanatory).
Y is 100 observations (time series) and X is 100 + 20 (20 to use for the
forecast horizon).
I can not make xreg work with the forecast function for an arima fit.
The "predict" function seems to be working but the
2001 Nov 26
1
Sorting Posix Data
I have a fairly large set of data with the following attributes:
>str(raw.data)
`data.frame': 1429 obs. of 16 variables:
$ TStamp :`POSIXlt', format: chr "2001-11-25 02:00:00" "2001-11-25
01:55:00" "2001-11-25 01:50:00" "2001-11-25 01:45:00" ...
$ iPDT.AHU14.14: num 0.0122 0.0125 0.0120 0.0120 0.0122 ...
$ iPDT.AHU14.15: num 0.0121
2009 Jul 15
2
storing lm() results and other objects in a list
to clean up some code I would like to make a list of arbitrary length
to store?various objects for use in a loop
sample code:
############ BEGIN SAMPLE ##############
# You can see the need for a loop already
linearModel1=lm(modelSource ~ .,mcReg)
linearModel2=step(linearModel1)
linearModel3=lm(modelSource ~ .-1,mcReg)
linearModel4=step(linearModel3)
#custom
linearModel5=lm(modelSource ~ .
2003 Nov 24
0
link between arima and arma fit
Hi dear sirs,
I am wondering why the fit of the time serie x with an arima and the fit of
diff(x) with an arma (same coeff p & d) differ one from another
here are the output of R:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> modelarma<-arma(diff(x),c(7,5))
> modelarma
Call:
arma(x = diff(x), order = c(7, 5))
Coefficient(s):
ar1 ar2 ar3 ar4 ar5 ar6 ar7 ma1 ma2
0.06078