Displaying 20 results from an estimated 700 matches similar to: "ARMAX Models in R"
2010 May 21
1
i have question about ARMAX
Pro,
I am PhD student , i am usuing Rational Expectations Model, I want to model different timeseries with ARMAX models in R because I think that ARMAX models will map best to these data. I want know the steps to use R for ARMAX models
I coudn't find any solutions in the R help and therefore I want to ask all of you.
Does anyone know how to solve this problem???
That would be
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
2011 Sep 09
2
Different results with arima in R 2.12.2 and R 2.11.1
Hello , I have estimated the following model, a sarima:
p=9
d=1
q=2
P=0
D=1
Q=1
S=12
In R 2.12.2
Call:
arima(x = xdata, order = c(p, d, q), seasonal = list(order = c(P, D, Q),
period = S),
optim.control = list(reltol = tol))
Coefficients:
ar1 ar2 ar3 ar4 ar5 ar6 ar7 ar8
ar9
0.3152 0.8762 -0.4413 0.0152 0.1500 0.0001 -0.0413 -0.1811
2008 Nov 20
2
Reformatting a table
Hi !
I am new to R. Can somebody help me in reformatting huge output files ,i.e, rearranging sets of columns in specific order.
For example: I have data for three compunds 1, 2 and 3
file1:
ID CA1 CA3 CA2 MA2 MA1 MA3
1 14 15 13 7 12 3
2 19 7 12 10 14 5
3 21 12 19 6 8 9
to
File 2:
ID CA1 CA2 CA3 MA1 MA2 MA3
1 14 13 15 12 7 3
2 19 12 7 14 10 5
3 21 19 12 8 6 9
or File3:
ID
2006 Dec 08
5
Remove " from a string
Hi all!
I have lots of functions called in the following pattern
'NameOfFunctionNumber' where the name always stays the same and the number
varies from 1 to 98.
Another function which I run in advance returns the number of the function
which has to be called next.
Now I want to combine 'NameOfFunction' with the 'Number' returned so that i
can call the desired function.
I
2009 Mar 26
1
arima, xreg, and the armax model
Hello all,
I''m having fun again with the arima function. This time I read in:
http://www.stat.pitt.edu/stoffer/tsa2/R_time_series_quick_fix.htm
<<It has recently been suggested (by a reliable source) that using xreg in
arima() does NOT fit an ARMAX model [insert slap head icon here]. This will
be investigated as soon as time permits.>>
(by R.H. Shumway & D.S. Stoffer)
2011 Feb 16
0
Arima contents
Hello,
I'm running a number of arima models using the "arima" function. Often,
when lag length gets too high, these model don't converge and an error
message appears as this:
> reg <- arima(y,order=c(7,0,7),xreg=isr)
Warning message:
In arima(y, order = c(7, 0, 7), xreg = isr) :
possible convergence problem: optim gave code=1
In this case, when you print the results
2009 Nov 16
1
ARMAX model fitting with arima
I am trying to understand how to fit an ARMAX model with the arima
function from the stats package. I tried the simple data below, where
the time series (vector x) is generated by filtering a step function
(vector u, the exogenous signal) through a lowpass filter with AR
coefficient equal to 0.8. The input gain is 0.3 and there is a 0.01
normal white noise added to the output:
x <- u
2009 Feb 20
0
residuals from a fractional arima model and other questions
Dear list and Martin,
I'm testing different approaches to fit an electricity demand time series and come upon the fracdiff package (v 1.3-1) for fitting fractional ARIMA models. The following questions are motivated by this package.
1. Despite having a help page, the residuals and fitted functions don't seem to have implementation, or did i miss something obvious? Alternatively, having a
2011 Nov 14
1
string to list()
I can get an array of strings for the data that I want using 'paste()' as
follows:
paste('ma', 1:am$arma[2], '=', coef(am)[1:am$arma[2] + am$arma[1]], sep='')
This results in a vector of strings like:
[1] "ma1=1.17760133668255" "ma2=0.649795570407939" "ma3=0.329456750858276"
What I would like is
fixed.pars <-
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
2003 Apr 30
2
Bug in arima?
I'm using the fixed argument in arima. Shouldn't ar4, ar5, and ar6
display as zero in the output?
Call:
arima(x = window(log(hhprice), start = c(1990, 1), end = c(2003, 3)),
order = c(7,
1, 0), xreg = window(ts.union(exa1 = lag(exa, -1), exa12 = lag(exa,
-12), exb1 = lag(exb, -1), exc1 = lag(exc, -1), exc12 = lag(exc,
-12)), start = c(1990, 1), end = c(2003, 3)),
2011 Sep 12
1
Difference in function arima estimation between 2.11.1 and R 2.12.2
Hello , I have estimated the following model, a sarima:
p=9
d=1
q=2
P=0
D=1
Q=1
S=12
In R 2.12.2
Call:
arima(x = xdata, order = c(p, d, q), seasonal = list(order = c(P, D, Q),
period = S),
optim.control = list(reltol = tol))
Coefficients:
ar1 ar2 ar3 ar4 ar5 ar6 ar7 ar8
ar9
0.3152 0.8762 -0.4413 0.0152 0.1500 0.0001 -0.0413 -0.1811
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),
2008 Jul 23
1
Time series reliability questions
Hello all,
I have been using R's time series capabilities to perform analysis for quite
some time now and I am having some questions regarding its reliability. In
several cases I have had substantial disagreement between R and other packages
(such as gretl and the commercial EViews package).
I have just encountered another problem and thought I'd post it to the list. In
this case,
2005 Oct 13
1
arima: warning when fixing MA parameters.
I am puzzled by the warning message in the output below. It appears
whether or not I fit the seasonal term (but the precise point of doing
this was to fit what is effectively a second seasonal term). Is there
some deep reason why AR parameters
("Warning message: some AR parameters were fixed: ...")
should somehow intrude into the fitting of a model that has only MA
terms?
>
2003 Dec 18
0
Help with predict.Arima with external regressor values
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),
2008 Sep 10
2
arima and xreg
Dear R-help-archive..
I am trying to figure out how to make arima prediction when I have a
process involving multivariate time series input, and one output time
series (output is to be predicted) .. (thus strictly speaking its an
ARMAX process). I know that the arima function of R was not designed
to handle multivariate analysis (there is dse but it doesnt handle
arma multivariate analysis, only
2004 Jun 22
3
[LLVMdev] Linearscan allocator bug?
Folks,
I'm running into something which looks like a bug in linearscan allocator. Of
course I can't be 100% sure it's not some unobvious mistake on my part, so
I'd like to hear your opinion.
First, I attach two files -- LLVM asm and the asm for my target. The problem
with assembler is: on line 171 it uses register gr2, which is copied from gr6
above, on line 161. The only
2010 Dec 06
10
R crashes when making graphs
hi,
i am running R with JGR and Deducer under Ubuntu Mint Lucid. since i updated to R 2.12 i can no longer make graphs - R just crashes.
the full error report was posted to launchpad (https://bugs.launchpad.net/ubuntu/+source/openjdk-6/+bug/675905) without any success so far.
anyone with a similar problem or helpful suggestions?
thanks!
kat