Displaying 20 results from an estimated 3000 matches similar to: "Newbie: Acf function"
2010 Apr 08
2
Meaning of "lag 0.2, 0.4,..." ?
Please see that correlogram for a arbitrary time series :
acf(zooreg(rnorm(39), start=as.yearmon("2008-01-01"), frequency=12))
What is the meaning of lag 0.2, 0.4, ........ in the plot? Those should not
be integers? Or I am missing something?
Thanks
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2002 Apr 11
3
new acf package
I'm a PhD student and I'm working with covariance function. I'm interested
to know if exist some packages in R to calculate and plot the
bidimensional Autocovariance Function. the input matrix is a matrix that
describe a spatial location over a 2-D space and I want to use it in the
same way I can use a time serie in the 1-D acf.
Thanks,
Nicola.
2002 Apr 11
3
new acf package
I'm a PhD student and I'm working with covariance function. I'm interested
to know if exist some packages in R to calculate and plot the
bidimensional Autocovariance Function. the input matrix is a matrix that
describe a spatial location over a 2-D space and I want to use it in the
same way I can use a time serie in the 1-D acf.
Thanks,
Nicola.
2010 Sep 26
1
acf function
Hi,
Im new to R so this question is quite fundamental.
Im trying to compare some autocorrelations generated by the acf function to some theoretical correlations. How can I have acces to just the autocorrelations, for computation?
This is some of my code:
> acf.data<-c(acf(x))
> acf.data
This is the R output:
$acf
, , 1
[,1]
[1,] 1.000000000
[2,]
2009 Aug 05
2
acf Significance
Hi List,
I'm trying to calculate the autocorrelation coefficients for a time
series using acf at various lags. This is working well, and I can get
the coefficients without any trouble. However, I don't seem to be able
to obtain the significance of these coefficients from the returned acf
object, largely because I don't know where I might find them.
It's clear that the acf
2003 Jun 06
2
R help: Correlograms
Hello,
I have time series and need to draw simple and partial correlograms with associated Q-statistics (the same as in EViews). Can I do it in R? Thanks
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2005 May 12
1
correlogram in spatial producing values outside [-1,1]
Dear all,
I'm using the correlogram function in the spatial library to calculate
spatial correlograms of radar data. However, I'm finding that the
resulting values are often outside the range [-1,1], usually only at
larger distances of separation.
I'm not sure whether to be overly concerned about this, or dismiss it as
some artefact of the data. Has anyone had similar experiences?
2010 Nov 07
1
When using ACF, receive error: no applicable method for 'ACF' applied to an object of class "c('double', 'numeric')"
I am guessing this is a very simple question, but this is only my second day
with R so it is all still a bit imposing.
I am trying to run an autocorrelation.
I imported a CSV file, which has one column labeled "logistic".
I ran the command:
ACF(data$logistic,maxLag=10)
However, I received the error:
Error in UseMethod("ACF") :
no applicable method for 'ACF'
2006 Aug 18
3
Query: how to modify the plot of acf
I need to modify the graph of the autocorrelation. I tried to do it through plot.acf but with no success.
1. I would like to get rid of the lag zero
2. I would like to have numbers on the x-axis only at lags 12, 24, 36, 48, 60, ...
Could anybody help me in this?
Any help will be appreciated
Thank you for your attention
Stefano
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2005 May 12
3
acf problem ?
Hi
I'm getting the following error that do not make sense to me, what am
Idoing wrong ?
> acf(Recsim[1,], lag.max=1)
Error in acf(Recsim[1, ], lag.max = 1) : 'lag.max' must be at least 1
Regards
EJ
2012 Mar 02
1
acf() plot of matrix cuts y-axis labels
Hello all,
I found a funny problem with y-axis labels when plotting acf(matrix) -
the labels are too close to one of the margins and cut in half.
Here's the problem:
test<-matrix(rnorm(200),ncol=4)
acf(test)
This doesn't fix the problem:
test<-matrix(rnorm(200),ncol=4)
par(mar=c(3,3,2,0.2),oma=c(0,0,0,0))
acf(test)
This does fix the margin. I understand why, but not sure why ONLY
2007 Mar 07
2
Calculating confidence limits on acf graphs
Hello,
I was wondering if anybody could help me with this?
I have plotted an acf function for a time series and am very happy with it.
Now I am interested in calculating for myself the two values for the confidence
intervals that are plotted on the graph of the acf.
The confidence intervals do not appear to be returned from the acf function (is this true?).
So far I haven't managed to
2010 Dec 08
1
Newbie trying to understand $ so I can understand acf function in stats
I am trying to understand the function acf
stats:::acf shows me the function
I am having trouble understanding the usage "$acf" in the following
acf <- array(.C(R_acf, as.double(x), as.integer(sampleT),
as.integer(nser), as.integer(lag.max), as.integer(type ==
"correlation"), acf = double((lag.max + 1L) * nser *
nser), NAOK =
2006 Nov 13
1
bug in acf (PR#9360)
Full_Name: Ian McLeod
Version: 2.3.1
OS: Windows
Submission from: (NULL) (129.100.76.136)
> There is a simple bug in acf as shown below:
>
> z <- 1
> acf(z,lag.max=1,plot=FALSE)
> Error in acf(z, lag.max = 1, plot = FALSE) :
> 'lag.max' must be at least 1
>
This is certainly a bug.
There are two problems:
(i) the error message is wrong since lag.max is
2009 Dec 22
2
ACF normalization.
Hi,
Can anyone please provide the formula used to compute ACF(nlme). I believe the one that is used in R is of the type mentioned on the website. Please correct me if I am wrong. The normalization of the numerator (Ch) has been done by 'N' where as I would like to do it by 'N-k'. Is there anyway in the present implementation of ACF to normalize it by 'N-k', where
2007 Nov 12
2
graphical parameters and acf
Hi,
I'm plotting 5 autocorrelation plots on one page. Using
par(mfrow=c(3,2)) everything comes out fine. However, for
each plot, it prints a title on top of each plot that says
Series followed by the variable name used in the plot. I
want to suppress those titles, but I also want a general
figure title on the bottom of the page. I've looked at the
Murrell book as well as the acf
2002 May 08
1
ts acf accessing to values
Hi,
I don't quite understant how can I access to the acf values from the
list produced by the acf function
Example:
library(ts)
t <- acf(ts.union(ts(1:10), ts(11:20)))
t$acf
> tmp$acf
, , 1
[,1] [,2]
[1,] 1.00000000 1.00000000
[2,] 0.70000000 0.70000000
[3,] 0.41212121 0.41212121
[4,] 0.14848485 0.14848485
[5,] -0.07878788 -0.07878788
[6,] -0.25757576
2012 Jan 10
1
Correlograms
I would like to make a correlogram in which I also have a correlation matrix
instead of one of the panels.
Is that possible?
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2016 Mar 23
3
ACF retardos múltiplos del periodo
Hola,
Estoy visualizando una serie temporal para determinar sus órdenes ARIMA y
no consigo lo siguiente: ¿Cómo puedo sacar la ACF de los retardos múltiplos
del periodo? Es decir, sólo ver en el gráfico ACF los retardos 12, 24, 36...
Gracias!!
David
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2008 May 25
2
A small modification of plot.acf (patch)
In one of my scripts I used plot.acf function, but I had to modify it
a little to suit my needs. Although my modifications are minor, I
believe some people might benefit from it.
The problem: currently, in cross-correlation plots main title captions
are constructed of 2 names separated by '&' symbol. Such captions
occupy too much horizontal space and usually don't fit in plot. A