Displaying 20 results from an estimated 600 matches similar to: "unexpected results involving the skellam distribution"
2006 Oct 03
1
do.call with Vectorial Argument
Dear All,
I am trying to use the do.call command to avoid tedious loops in R
when I need to call repetitively a function.
I am experiencing a problem when the arguments of a function are given
with a vector (I need to express then this way to be able later on to
integrate them numerically with the adapt package).
Consider the small script:
remove(list=ls())
#library(adapt)
# first a list of the
2006 Sep 22
4
Creating Movies with R
Dear All,
I'd like to know if it is possible to create animations with R.
To be specific, I attach a code I am using for my research to plot
some analytical results in 3D using the lattice package. It is not
necessary to go through the code.
Simply, it plots some 3D density profiles at two different times
selected by the user.
I wonder if it is possible to use the data generated for different
2013 Mar 18
1
"save scores" from sem
I'm not aware of any routine that those the job, although I think that
it could be relatively easily done by multiplication the manifest
variable vector with the estimates for the specific effect.
To make an example:
v1; v2; v3; v4 are manifest variables that loads on one y latent
variablein a data frame called "A"
the code for the model should be like:
model <-specifymodel(
y
2012 Sep 27
0
problems with mle2 convergence and with writing gradient function
Dear R help,
I am trying solve an MLE convergence problem: I would like to estimate
four parameters, p1, p2, mu1, mu2, which relate to the probabilities,
P1, P2, P3, of a multinomial (trinomial) distribution. I am using the
mle2() function and feeding it a time series dataset composed of four
columns: time point, number of successes in category 1, number of
successes in category 2, and
2012 Oct 11
2
model selection with spg and AIC (or, convert list to fitted model object)
Dear R Help,
I have two nested negative log-likelihood functions that I am optimizing
with the spg function [BB package]. I would like to perform model
selection on these two objective functions using AIC (and possibly
anova() too). However, the spg() function returns a list and I need a
fitted model object for AIC(), ICtab() [bbmle package], or anova().
How can I perform AIC-based model
2012 Oct 05
2
problem with convergence in mle2/optim function
Hello R Help,
I am trying solve an MLE convergence problem: I would like to estimate
four parameters, p1, p2, mu1, mu2, which relate to the probabilities,
P1, P2, P3, of a multinomial (trinomial) distribution. I am using the
mle2() function and feeding it a time series dataset composed of four
columns: time point, number of successes in category 1, number of
successes in category 2, and
2007 Oct 23
1
How to avoid the NaN errors in dnbinom?
Hi, The code below is giving me this error message:
Error in while (err > eps) { : missing value where TRUE/FALSE needed
In addition: Warning messages:
1: In dnbinom(x, size, prob, log) : NaNs produced
2: In dnbinom(x, size, prob, log) : NaNs produced
I know from the help files that for dnbinom "Invalid size or prob will
result in return value NaN, with a warning", but I am not able
2013 Apr 09
0
[R-SIG-Finance] EM algorithm with R manually implemented?
Moved to R-help because there's no obvious financial content.
Michael
On Sat, Apr 6, 2013 at 10:56 AM, Stat Tistician
<statisticiangermany at gmail.com> wrote:
> Hi,
> I want to implement the EM algorithm manually, with my own loops and so.
> Afterwards, I want to compare it to the normalmixEM output of mixtools
> package.
>
> Since the notation is very advanced, I
2009 Mar 30
0
Problem in S4 object displaying from within a Java application using JRI
I am using JRI (Java R Interface) library in order to call R from within my
Java application. But since the "rmu1" and "rmu2" ,see the following code,
are objects of type S4 once i run the application the value of Null will be
returned for both of them. On this regard, i would appreciate it if anyone
can tell me how i am going to display and/ or convert these objects to Java
2009 May 22
0
EM algorithm mixture of multivariate
Hi, i would to know, if someone have ever write the code to estimate the
parameter (mixing proportion, mean, a var/cov matrix) of a mixture of two
multivariate normal distribution. I wrote it and it works (it could find
mean and mixing proportion, if I fix the var/cov matrix), while if I fix
anything, it doesn't work. My suspect is that when the algorithm iterates
the var/cov matrix, something
2009 May 22
0
EM algorithm mixture of multivariate gaussian
Hi, i would to know, if someone have ever write the code to estimate the
parameter (mixing proportion, mean, a var/cov matrix) of a mixture of two
multivariate normal distribution. I wrote it and it works (it could find
mean and mixing proportion, if I fix the var/cov matrix), while if I fix
anything, it doesn't work. My suspect is that when the algorithm iterates
the var/cov matrix, something
2006 May 21
2
nls & fitting
Dear All,
I may look ridiculous, but I am puzzled at the behavior of the nls with
a fitting I am currently dealing with.
My data are:
x N
1 346.4102 145.428256
2 447.2136 169.530634
3 570.0877 144.081627
4 721.1103 106.363316
5 894.4272 130.390552
6 1264.9111 36.727069
7 1788.8544 52.848587
8 2449.4897 25.128742
9 3464.1016 7.531766
10 4472.1360 8.827367
11
2011 May 16
0
SEM Model Not Converging
I'm trying to build a SEM using the sem package. I'll attach my model
specification below.
When I turn debug=TRUE, it seems as if I'm getting to convergence
because I get this message:
Successive iterates within tolerance.
Current iterate is probably solution.
However, at the end of the process I get this message:
Warning message:
In sem.default(ram = ram, S = S, N = N,
2013 Mar 31
0
Skewness of fitted mixture not correct?
I fitted a gaussian mixture to my financial data. The data can be found
here: http://uploadeasy.net/upload/32xzq.rar
I look at the density with
plot(density(dat),col="red",lwd=2)
this has a skew of
library(e1071)
skewness(dat)
-0.1284311
Now, I fit a gaussian mixture according to:
f(l)=πϕ(l;μ1,σ21)+(1−π)ϕ(l;μ2,σ22)
with:
2007 Mar 13
0
multiplying matrix by vector of times
On 8/3/07 22:12, "Gad Abraham" <g.abraham at ms.unimelb.edu.au> wrote:
> Laura Hill wrote:
>>
>>
>> On 7/3/07 00:15, "Gad Abraham" <g.abraham at ms.unimelb.edu.au> wrote:
>>
>>>> On 6 Mar 2007, at 08:54, Laura Hill wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> My name is
2008 Feb 24
0
problem with ML estimation
dear list,
as a part my problem. I have to estimate some parameters using ML
estimation. The form of the likelihood function
is not straight forward and I had to use a for loop to define the function.
I used "optim" to maximise the result but
was not sure of the programme.
To validate my results, I tried to write a function to obtain the MLE of a
bivariate normal in the same manner.
On
2007 Apr 27
1
error returned by "make check" in R-2.5.0
Today I tried to install the R-2.5.0 (currently running R-2.4.1) on
Mandriva Linux. The ./configure and make commands seem to run fine,
but "make check" gives the following messages:
running regression tests
make[3]: Entering directory `/home/ethomp04/R-2.5.0/tests'
running code in 'reg-tests-1.R' ...make[3]: *** [reg-tests-1.Rout] Error 1
make[3]: Leaving directory
2008 Dec 04
0
integration within maximum likelihood
Hi:
I'm trying to estimate a latent variable model in mnl discrete choice
framework using R. I need to do first a uni dimensional integral
within each observation (row) in the database and then sum over
observations. I'm stacked in the point shown below. Apparently I have
a dimensionality problem in the definition of the integral. Maybe it
does not identify that what I need is only one
2010 Jun 13
1
using latticeExtra plotting confidence intervals
I am wanting to plot a 95% confidence band using segplot, yet I am wanting
to have groups. For example if I have males and females, and then I have
them in different races, I want the racial groups in different panels. I
have this minor code, completely made up but gets at what I am wanting, 4
random samples and 4 samples of confidence, I know how to get A & B into one
panel and C&D in to
2003 Feb 19
1
getting/storing the name of an object passed to a function
Hi
I have a couple of functions that work on the object created by another R
command and then print out or summarise the results of this work.
The main function is defined as:
hotelling.t <- function(obj)
{
#internal commands
}
I then have print.hotelling.t() that takes the list returned by hotelling.t
and prints it with some extra significance calculations, formatting, etc.
I want to