Displaying 20 results from an estimated 900 matches similar to: "A question about forecasting with R"
2010 Jan 11
1
HoltWinters Forecasting
Hi R-users,
I have a question relating to the HoltWinters() function. I am trying to
forecast a series using the Holt Winters methodology but I am getting some
unusual results. I had previously been using R for Windows version 2.7.2 and
have just started using R 2.9.1. While using version 2.7.2 I was getting
reasonable results however upon changing versions I found I started to see
unusual
2009 Mar 27
4
A beginner's question
I am a new R-language user. I have set up a data frame "mydata",one of
the colume of which is "skill". Now I want to select the observations
whose "skill" value is equal to 1,by what command can I get it?
2009 Mar 31
2
Does R support double-exponential smoothing?
I want to use double-exponential smoothing to forecast time series
datas,but I couldn't find it in the document,does R support this
method?
2009 Mar 30
2
A simple problem
I am a new R user. Now I have some problem while I use R. I have set
up a data frame called "mydata". One of the colume of it was "skill".
Now I want to select the observations of the frame whose "skill" value
is 1,by what command can I get it?
2010 Oct 07
1
Forecasting with R/Need Help. Steps shown below with the imaginary data
1. This is an imaginary data on monthly outcomes of 2 years and I want to forecast the outcome for next 12 months of next year.
data Data1;
input Yr Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec;
datalines;
2008 12 13 12 14 13 12 11 15 10 12 12 12
2009 12 13 12 14 13 12 11 15 10 12 12 12
;
run;
I converted the above data into the below format to use it in R as it was giving error: asking
2012 Jan 07
1
using deltat parameter in time series in HoltWinters prediction
Hi.
I have to forecast a time series of a Internet network traffic bitrate.
The data are in file
http://www.forumaltavilla.it/joomla/datitesi/dati.datand the sampling
time is every 0.05 seconds.
Now, i want to use HoltWinters forecasting. This is my script.
dt=1.58443823e-9 #0.05 seconds in years
dati.ts=ts(scan("dati.dat"),start=0,deltat=dt)
model=HoltWinters(dati.ts)
2011 Mar 08
0
HoltWinters forecasting method
Dear All,
I was wondering why the forecast for an additive HoltWinters model is given
by Yhat[t+h] = a[t] + h * b[t] + s[t + 1 + (h - 1) mod p].
I am a student and new to time series analysis and forecasting. That said, I
considered t = 13 and h = 1: Yhat[13+1] = a[13] + b[13] + s[13 + 1]
It seems odd that to predict Yhat[14], you would need a s[14] which in turn
depends on Y[14], given that
2006 Sep 02
0
New forecasting bundle of packages
v1.0 of the forecasting bundle of packages is now on CRAN and will
propagate to mirrors shortly.
The forecasting bundle of R packages provides new forecasting methods,
and graphical tools for displaying and analysing forecasts. It comprises
the following packages:
* forecast: Functions and methods for forecasting.
* fma: All data sets from Makridakis, Wheelwright and Hyndman
2006 Sep 02
0
New forecasting bundle of packages
v1.0 of the forecasting bundle of packages is now on CRAN and will
propagate to mirrors shortly.
The forecasting bundle of R packages provides new forecasting methods,
and graphical tools for displaying and analysing forecasts. It comprises
the following packages:
* forecast: Functions and methods for forecasting.
* fma: All data sets from Makridakis, Wheelwright and Hyndman
2003 Sep 03
2
problem with HoltWinters
Dear helpers
I'm having a problem with function HoltWinters from package ts. I have a time series that I want to fit an Holt-Winters model and make predictions for the next values. I've already built an object of class ts to serve as input to HoltWinters. But then I get an error; I've used HoltWinters a lot of times and this never hapened
> data.HW<-HoltWinters(data.ts)
Error
2012 Apr 26
2
HoltWinters() fitted values
Hi everyone,
I'm using the HoltWinters() function to do a time series analysis. The
function only returns the back fitted values ($fitted) after the first year
of data, which is my case, is a little more than half. However, when I use
the plot() function, it plots the back fit for almost the entire data set.
Any ideas on how to extract the fitted values going all the way back to the
start
2012 Dec 04
4
partial analisys of a time series
Dear list members
I want to analyze separately the months of a time series. In other words, I
want to plot and fit models for each month separately.
Taking the example of
http://a-little-book-of-r-for-time-series.readthedocs.org/en/latest/src/timeseries.html
births <- scan("http://robjhyndman.com/tsdldata/data/nybirths.dat")
birthstimeseries <- ts(births, frequency=12,
2008 May 16
1
HoltWinters fitted level parameter not bounded between 0 and 1 (PR#11469)
Full_Name: John Bodley
Version: 2.5.1 (2007-06-27)
OS: Windows XP
Submission from: (NULL) (12.144.182.66)
I was fitting a number of time series in R using the stats::HoltWinters method
to define a single exponential smoothing model, i.e., beta = gamma = 0.
I came across an example where the fitted value of alpha was not defined in the
[0, 1] interval which seems to violate the lower and upper
2011 Nov 04
1
HoltWinters in R 2.14.0
Hey All,
First time on these forums. Thanks in advance.
Soooo... I have a process that was functioning well before the 2.14 update.
Now the HoltWinters function is throwing an error whereby I get the
following:
Error in HoltWinters(sales.ts) : optimization failure
I've been looking around to determine why this happens (see if I can test
the data beforehand) but I haven't come
2012 Nov 28
1
How to change smoothing constant selection procedure for Winters Exponential Smoothing models?
Hello all,
I am looking for some help in understanding how to change the way R
optimizes the smoothing constant selection process for the HoltWinters
function.
I'm a SAS veteran but very new to R and still learning my way around.
Here is some sample data and the current HoltWinters code I'm using:
rawdata <- c(294, 316, 427, 487, 441, 395, 473, 423, 389, 422, 458, 411,
433, 454,
2008 Sep 14
1
need help please (HoltWinters function)
every time i try to run HoltWinters i get this error message:
> HoltWinters(z, seasonal="additive")
Error in decompose(ts(x[1:wind], start = start(x), frequency = f), seasonal)
:
time series has no or less than 3 periods
what's going on? somebody please help me.
--
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2007 Feb 27
2
.C HoltWinters
Hello,
I would like to look at the compiled C code behind HoltWinters from the
stats package. Is that possible? If so where do I find it?
thanks,
Spencer
[[alternative HTML version deleted]]
2012 Mar 13
4
how to find best model of time series?
i have data in one file below like & (i have such type of file =200,each
file have below type of data)
>t
-0.15264004
0.056076439
-0.07276116
-0.00917326
-0.02069089
-0.00416232
-0.07225855
-0.02654577
-0.06131410
-0.09380202
0.057414014
-0.05239976
0.014397612
0.016145161
-0.00670587
0.018696335
0.036943654
-0.02450233
0.031161705
0.006513503
-0.02892329
-0.00831519
-0.00877744
2005 Mar 05
1
Object containing different classes
Hi,
i want to create an object which contains different classes: for example i
have some time series and test if ARIMA models are best than HoltWinters
models: for each of my time serie i want to collect in an unique object
which model was the best: for some it will be an HoltWinters class and for
some other an Arima class.
is there any solution?? thanks in advance, with my best, erik sauleau
2007 Nov 16
1
Exponential Smoothing for ggplot2's stat_smooth()
Hello everyone,
I was wondering if anyone was aware of a way in which I could use ggplot's
stat_smooth() function for add an exponential moving average.
I was thinking that I could maybe use something like:
>myggplot + stat_smooth (method = 'HoltWinters( data , .9 , 0, 0)')
but my efforts were futile.
Perhaps there is a way to write my own custom method to throw into