Displaying 20 results from an estimated 1000 matches similar to: "optim error in arima"
2008 Jul 29
1
optim fails when using arima
Hi all,
I?m using the arima() function to study a time series but it gives me
the following error:
Error en optim(init[mask], armafn, method = "BFGS", hessian = TRUE,
control = optim.control, :
non-finite finite-difference value [3]
I know that I can change the method of the arima() to "CSS" instead of
"ML" but I'm specially interested in using
2008 Jun 26
1
stationary "terminology" time series question
This is not exactly an R question but the R code below may make my
question more understandable.
If one plots sin(x) where x runs from -pi to pi , then the curve hovers
around zero obviously. so , in a"stationary in the mean" sense,
the series is stationary. But, clearly if one plots the acf, the
autocorrelations at lower lags are quite high and, in the "box jenkins"
2006 Nov 30
1
bug in arima? (PR#9404)
I don't think arima works exactly the way one would expect when there is differencing. What I think should happen is that by
default the mean of the differenced series is estimated and if include.mean=F, then it is not. This is not what happens. Instead
when there is differencing the include.mean argument is ignored.
Now I guess, someone could argue that the mean of the original series
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
2015 Apr 20
2
Fix for bug in arima function
There is currently a bug in the arima function. Namely, for arima models with differencing or seasonal differencing, the innovation variance estimator uses the wrong denominator whenever xreg is non-null. This is the case, for example, when fitting an ARIMA(p,1,q) model with a drift term (common in financial applications). I reported the bug (and a fix) at
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
2011 Oct 21
2
Arima Models - Error and jump error
Hi people,
I´m trying to development a simple routine to run many Arima models result
from some parâmeters combination.
My data test have one year and daily level.
A part of routine is:
for ( d in 0:1 )
{ for ( p in 0:3 )
{ for ( q in 0:3 )
{ for ( sd in 0:1 )
{ for ( sp in 0:3 )
{ for ( sq in 0:3 )
{
2015 May 21
3
Fix for bug in arima function
On 21 May 2015, at 12:49 , Martin Maechler <maechler at lynne.stat.math.ethz.ch> wrote:
>>>>>> peter dalgaard <pdalgd at gmail.com>
>>>>>> on Thu, 21 May 2015 11:03:05 +0200 writes:
>
>> On 21 May 2015, at 10:35 , Martin Maechler <maechler at lynne.stat.math.ethz.ch> wrote:
>
>>>>
>>>> I noticed that
2006 Jul 06
2
KPSS test
Hi,
Am I interpreting the results properly? Are my conclusions correct?
> KPSS.test(df)
---- ----
KPSS test
---- ----
Null hypotheses: Level stationarity and stationarity around a linear trend.
Alternative hypothesis: Unit root.
----
Statistic for the null hypothesis of
level stationarity: 1.089
Critical values:
0.10 0.05 0.025 0.01
0.347 0.463
2009 Mar 03
2
modifying a built in function from the stats package (fixing arima)
Dear members of the list,
I'm a beginner in R and I'm having some trouble with: "Error in
optim(init[mask], armafn, method = "BFGS", hessian = TRUE, control =
optim.control, :
non-finite finite-difference value [8]"
when running "arima".
I've seen that some people have come accross the same problem:
2009 Jan 27
2
optim() and ARIMA
dhabby wrote:
Last week I run in to a lot a problems triyng to fit an ARIMA model to a
time series. The problem is that the internal process of the arima
function
call function "optim" to estimate the model parameters, so far so good...
but my data presents a problem with the default method "BFGS" of the
optim
function, the output error looks like this:
2006 Jul 06
1
Access values in kpssstat-class
Hi,
How can I access the Values stored in kpssstat-class given by KPSS.test function and store it in a variable.
For example:
>x <- rnorm(1000)
>test <- KPSS.test(ts(x))
>test
---- ----
KPSS test
---- ----
Null hypotheses: Level stationarity and stationarity around a linear trend.
Alternative hypothesis: Unit root.
----
Statistic for the null
2015 May 21
2
Fix for bug in arima function
On 21 May 2015, at 10:35 , Martin Maechler <maechler at lynne.stat.math.ethz.ch> wrote:
>>
>> I noticed that the 3.2.1 release cycle is about to start. Is there any
>> chance that this fix will make it into the next version of R?
>>
>> This bug is fairly serious: getting the wrong variance estimate leads to
>> the wrong log-likelihood and the wrong
2007 Dec 08
2
time series tests
Hi all,
Can anyone clear my doubts about what conclusions to take with the following what puts of some time series tests:
> adf.test(melbmax)
Augmented Dickey-Fuller Test
data: melbmax
Dickey-Fuller = -5.4075, Lag order = 15, p-value = 0.01
alternative hypothesis: stationary
Warning message:
p-value smaller than printed p-value in: adf.test(melbmax)
2005 Mar 09
1
about kpss.test()
Hi All,
First of all, could you tell me what the "KPSS Level"
in the output of the test means?
I have a series, x, of periodic data and tried
kpss.test() on it to verify its stationarity. The
tests
gave me the p-value above 0.1. Since the null
hypothesis N0 is that the series _is_ stationary, this
means that I cannot reject N0. But the series does
look
periodic!
So does all this
2003 Jul 16
1
arima.sim problems (PR#3495)
Full_Name: Gang Liang
Version: 1.7.1
OS: Debian/Woody
Submission from: (NULL) (192.6.19.190)
> print(arima.sim(list(ar=.3,order=c(1,1,1)), 30))
[1] 0.00000000 0.10734243 0.02907301 -1.23441659 -0.98819317 -2.82731975
[7] -2.69052512 -4.22884756 -5.02820635 -5.41514613 -6.20486350 -7.01040649
[13] -6.78121289 -5.41111810 -4.96338053 -5.42395408 -6.22741444 -5.75228153
[19] -6.07346580
2005 Mar 08
2
The null hypothesis in kpss test (kpss.test())
is that 'x' is level or trend stationary. I did this
> s<-rnorm(1000)
> kpss.test(s)
KPSS Test for Level Stationarity
data: s
KPSS Level = 0.0429, Truncation lag parameter = 7,
p-value = 0.1
Warning message:
p-value greater than printed p-value in:
kpss.test(s)
My question is whether p=0.1 is a good number to
reject
N0? On the other hand, I have a
2007 Nov 26
3
Time Series Issues, Stationarity ..
Hello,
I am very new to R and Time Series. I need some help including R codes
about the following issues. I' ll really appreciate any number of
answers...
# I have a time series data composed of 24 values:
myinput = c(n1,n2...,n24);
# In order to make a forecasting a, I use the following codes
result1 = arima(ts(myinput),order = c(p,d,q),seasonal = list(order=c(P,D,Q)))
result2 =
2015 May 20
2
Fix for bug in arima function
I noticed that the 3.2.1 release cycle is about to start. Is there any
chance that this fix will make it into the next version of R?
This bug is fairly serious: getting the wrong variance estimate leads to
the wrong log-likelihood and the wrong AIC, BIC etc, which can and does
lead to suboptimal model selection. If it's not fixed, this issue will
affect every student taking our time series