Displaying 20 results from an estimated 1000 matches similar to: "HoltWinters() - p-values for alpha, beta and gamma"
2008 May 16
0
HoltWinters fitted level parameter not bounded between 0 (PR#11473)
I get John's value (48.8789) in 2.7.0 and R-devel (both on Ubuntu).
Really seems to be a numeric issue:
> HoltWinters(x, beta = 0, gamma = 0)$alpha
alpha
48.87989
> HoltWinters(x * 1.0000000001, beta = 0, gamma = 0)$alpha
alpha
0.6881547
> HoltWinters(x * 1.00000000001, beta = 0, gamma = 0)$alpha
alpha
48.87989
Providing starting values seems to help, but not
2012 Apr 26
2
HoltWinters() fitted values
Hi everyone,
I'm using the HoltWinters() function to do a time series analysis. The
function only returns the back fitted values ($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
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
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
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
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)
2008 May 17
0
HoltWinters fitted level parameter not bounded between 0 (PR#11478)
An update on this:
I just patched HoltWinters() to use optimize() in the univariate case,
and it now computes the correct value.
David
John Bodley wrote:
> Hi,
>
> Thanks for the quick response. I upgraded by version of R on Windows to the
> latest (2.7.0) and re-ran the analysis and get the same result of 48.87989.
>
> The original time series was a non-regular zoo()
2012 Jan 23
1
HoltWinters problem
I am running R version 2.14.1 with up-to-date packages.
When running the HoltWinters function as in
HoltWinters(logjj,gamma=FALSE,beta = TRUE) i get back
Smoothing parameters:
alpha: 0.1692882
beta : TRUE
gamma: FALSE
In the old days (several weeks ago) i used to get back the actual beta value
used as the documentation states. Is this a reporting change? How can I get
the value of
2008 May 16
0
HoltWinters fitted level parameter not bounded between 0 (PR#11472)
It doesn't do it on my system (I get a value of about 0.688 in R 2.7.0
patched on Linux), and 2.5.1 is not current. Does a better starting value
help?
However, HoltWinters is using optim() in a case it is not designed for
(one-dimensional optimization): see the note on its help page. I think
this could easily be changed, but as HoltWinters is contributed code
I am Cc:ing the author for
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]]
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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2012 Oct 10
0
HoltWinters
Hi,
I am trying to fit the HoltWinters exponential smoothing on a monthly time
series data in R. My questions are:
1. I know that the level, trend and seasonality are updated over time. So
are the output coefficients a, b and s1-s12 for a specific time t (a,b and
s12 for last observataion for example) ?
2. I am trying to work out the fitted values but I could not figure out
the h value used in
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
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
2002 Sep 11
1
one question about title
Dear,
Thanks for your help. My question is the title can not completely show in the drawing area when the title is too long.
So, I need to change the value of cex.main each time. Could you help me to control the title display area?
Regrad,
ken
-----Original Message-----
From: Patrick Connolly [mailto:p.connolly at hortresearch.co.nz]
Sent: Wednesday, September 11, 2002 4:41 AM
To: Ken
2013 Apr 04
1
Freenas domU network performance issue
Hi guys,
I''m running a freenas domU (FreeBSD 8.3 based, ZFS v28, 2 vcpus mapped to
the same HT capable core) to serve storage for all purpose including other
domUs running on the same host. I did some study to understand how well it
works and the result is kind of confusing.
In summary, the network performance between domains on the same host is
worse than expected. And NFS service to
2007 Dec 08
1
FW: R memory management
Hi,
I'm using R to collect data for a number of exchanges through a socket
connection and constantly running into memory problems even though task I
believe is not that memory consuming. I guess there is a miscommunication
between R and WinXP about freeing up memory.
So this is the code:
for (x in 1:length(exchanges.to.get)) {
tickers<-sqlQuery(channel,paste("SELECT Symbol
2009 Oct 03
1
Passing lists and R memory usage growth
Hello,
I can't think of an explanation for this memory allocation behaviour
and was hoping someone on the list could help out.
Setup:
------
R version 2.8.1, 32-bit Ubuntu 9.04 Linux, Core 2 Duo with 3GB ram
Description:
------------
Inside a for loop, I am passing a list to a function. The function
accesses various members of the list.
I understand that in this situation, the entire
2004 Jan 26
3
Samba and Window XP write performance
I did some testing using samba-3.0.0 as a server and two identical clients
one Running W2K and other running Win XP pro.
If I write a big file using the W2K client, I'm getting about 25 Mbytes/sec
but if I run the same testing using the Win XP Pro, this
client only is able to get 12.5 Mbytes/sec.
There is a problem between XP and samba?
2013 Sep 06
1
Gluster native client very slow
Hello,
I'm testing a two nodes glusterfs distributed cluster (version 3.3.1-1)
on Debian 7. The two nodes write on the same iscsi volume on a SAN.
When I try to write an 1G file with dd, I have the following results :
NFS : 107 Mbytes/s
Gluster client : 8 Mbytes/sec
My /etc/fstab on the client :
/etc/glusterfs/cms.vol /data/cms glusterfs defaults 0 0
I'd like to use the gluster