Displaying 20 results from an estimated 10000 matches similar to: "Prediction errors from forecast()?"
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
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
2009 Jan 23
1
forecasting error?
Hello everybody!
I have an ARIMA model for a time series. This model was obtained through an
auto.arima function. The resulting model is a ARIMA(2,1,4)(2,0,1)[12] with
drift (my time series has monthly data). Then I perform a 12-step ahead
forecast to the cited model... so far so good... but when I look the plot of
my forecast I see that the result is really far from the behavior of my time
2008 Oct 15
1
Forecasting using ARIMAX
Dear R-helpers,
I would appreicate if someone can help me on the transfer parameter in ARIMAX and also see what I am doing is correct.
I am using ARIMAX with 2 Exogeneous Variables and 10 years data are as follows:
DepVar Period, depVar, IndepVar1 Period, indepVar1, IndepVar2 Period, indepVar2
Jan 1998,708,Jan 1998,495,Jan 1998,245.490
Feb 1998,670,Feb 1998,421.25,Feb 1998,288.170
Mar
2008 Aug 12
1
arima forecast function
hi:
I am trying to fit prediction intervals for an arima object. My search led
me to the link:
http://finzi.psych.upenn.edu/R/library/forecast/html/forecast.Arima.html
which has the function "forecast", as I wanted. However, when I try to run
it in R, I get the message:
Error in plot(forecast(fit)) : could not find function "forecast"
Even the example provided on the page
2010 Dec 08
1
Question on ARIMA Prediction
Dear all,
I'm new to R and time series analysis. I'd appreciate if you could shed
light on my problem.
Here is what I have been trying to do:
1. I fit the model ARIMA(1,0,0) with the training dataset xdata[1:100]
fitit = arima(xdata, order=c(1,0,0)
2. I have some current observations in the buffer. Say that
buf = xdata_new[1:20]
3. I'm trying to forecast the xdata_new[21] based on
2009 Dec 04
1
Saving predict
Hi all,,Im using function arima()
I.e
series is my data
model<-arima(series,c(1,0,0))
forecast<-predict(model,80)
I want to create a variable:
b1<-forecast$pred - 1.96*forecast$se
and save in a txt file
but using this:
save(b1, file= "b1.txt")
creates afile butwith this inside:
]{HQ ~|LJIiW*-l)% )m#),
RIiSfdbGur9p94; H"L#Rez
1y3pN8{,I6W!6=
{6l?OMw_5KZ+
=
2012 May 04
1
Problems Exporting R Output to an xls file need help
Hello R users,
I want to export to an xls or .csv some predictions I produced with the
auto.arima and forecast functions.
A detail of all my work is presented below. I loaded a package called
dataframes2xls and tried to use the function write.xls without any success.
Can anybody help me figure this out? How could I get R to export the output
to an xls file?
Any help will be greatly
2012 Sep 10
2
predict arima
Hello, I have a question regarding the predict command for ARIMA models. Why do I not have to give any input except the number of steps for the forecast? Which input value is used (in my case for “y(t)”)? Will the last parameter of the estimate vector be used (in my example “6”)? x <- c(1,2,3,4,5,6)model <- arima(x, order=c(1,0,0), method="ML")predict(model, n.ahead = 1) ->
2011 Jul 04
1
forecast: bias in sampling from seasonal Arima model?
Dear all,
I stumbled upon what appears to be a troublesome issue when sampling from an
ARIMA model (from Rob Hyndman's excellent 'forecast' package) that contains
a seasonal AR component.
Here's how to reproduce the issue. (I'm using R 2.9.2 with forecast 2.19;
see sessionInfo() below).
First some data:
> x <- c(
0.132475, 0.143119, 0.108104, 0.247291, 0.029510,
2007 Oct 24
0
Package forecast
Hello All,
I trying to use the function auto.arima(....) from package forecast but I
have a problem.
My steps after I used the function auto.arima(...)
I create the time series like this:
>bbrass = scan("C:/Program Files/R/data PTIN/my_file.dat")
>regts.start = ISOdatetime(2006, 7, 1, hour=0, min=0, sec=0, tz="GMT") #2006
07 01 00
>regts.end = ISOdatetime(2006, 7,
2009 Mar 05
3
Time Series - ARIMA differencing problem
Hi,
I have been using this website (
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm
http://www.stat.pitt.edu/stoffer/tsa2/Rissues.htm ) to help me to fit ARIMA
models to my data. At the moment I have two possible methods to use.
Method 1
If I use
arima(ts.data, order=c(1,2,0), xreg=1:length(ts.data))
then the wrong value for the intercept/mean is given (checked on SPSS and
Minitab) and
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,
2009 Jun 23
1
Forecast GARCH model
Hi,
I've fitted a GARCH(1,1) for the residuals of my time serie (X).
X is an ARMA(1,1) process.
Now I want to do a n-step forecast for X, knowing these processes. How can I
do this?
I know that there's a command:
predict() for ARIMA processes and so on, but what about GARCH?
I've got:
arma=arima(x, order=c(1,0,1))
(...)
garch11<-garch(residuals(x),order = c(1, 1))
2007 Dec 04
1
Best forecasting methods with Time Series ?
Hello,
In order to do a future forecast based on my past Time Series data sets
(salespricesproduct1, salespricesproduct2, etc..), I used arima() functions
with different parameter combinations which give the smallest AIC. I also
used auto.arima() which finds the parameters with the smallest AICs. But
unfortuanetly I could not get satisfactory forecast() results, even
sometimes catastrophic
2010 Mar 19
1
Arima forecasting
Hello everyone,
I'm doing some benchmark comparing Arima [1] and SVR on time series data.
I'm using an out-of-sample one-step-ahead prediction from Arima using
the "fitted" method [2].
Do someone know how to have a two-steps-ahead forecast timeseries from Arima?
Thanks,
Matteo Bertini
[1] http://robjhyndman.com/software/forecast
[2] AirPassengers example on page 5
2010 Apr 29
1
forecast in arima
Hello,
I have a question about forecast under model arima(1,1,1).
I construct this model on 1000 observations and find the forecast for
following, for example, 100 observations.
But it' s necessary for me to get the predicted values of the previous 100
observations and compare it with actual values.
Please, tell me what should be done.
Thank you very much
[[alternative HTML version
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
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
2017 Oct 06
1
Formatting the dates generated by the forecast function
Dear friend, hope you are doing great,
I have the following code:
> myTseriesData <- ts(data[,2], start=c(2000,01), end=c(2017,9),
frequency=12)
> myTseriesModel <- auto.arima(myTseriesData, d=1, D=1)
> myTseriesForecast <- forecast(myTseriesModel, h=12)
> # I want to be able to format the dates generated by the forecast function
is there a way to change the format of the