Displaying 20 results from an estimated 8000 matches similar to: "Multivariate mixture distributions"
2010 Nov 22
0
hierarchical mixture modelling
Hi folks,
I have circular data that I'd like to model as a mixture of a uniform
and a Von Mises centered on zero. The data are from 2 groups of human
participants, where each participant is measured repeatedly within
each of several conditions. So, the data frame would look something
like:
########
design = expand.grid(
person = 1:20
, variable1 = 1:2
, variable2
2009 Aug 06
0
Fitting Mixture of Non-Central Student's t Distributions
Dear Ingmar & Dave,
Thanks a lot for your help and sorry for the late reply.
Finally, I've found a way to separate the mixture of distributions
(empirically). But the gamlss package looks great, I'm sure it will help
me during my further studies.
Kind regards,
Susanne
On 15 Jun 2009, at 20:09, Ingmar Visser wrote:
> Dear Susanne & Dave,
>
> The gamlss package family
2002 Dec 04
1
Mixture of Multivariate Gaussian Sample Data
Hey, I am confused about how to generate the sample data from a mixture of
Multivariate Gaussian ditribution.
For example, there are 2 component Gaussian with prior
probability of 0.4 and 0.6,
the means and variances are
u1=[1 1]', Cov1=[1 0;0 1]
and
u2=[-1 -1]', Cov2=[1 0;0 1]
repectively.
So how can I generate a sample of 500 data from the above mixture
distribution?
Thanks.
Fred
2012 Mar 05
1
Fitting & evaluating mixture of two Weibull distributions
Hello,
I would like to fit a mixture of two Weibull distributions to my data, estimate the model parameters, and compare the fit of the model to that of a single Weibull distribution.
I have used the mix() function in the 'mixdist' package to fit the mixed distribution, and have got the parameter estimates, however, I have not been able to get the log-likelihood for the fit of this model
2008 Apr 03
1
How to ask for *fixed* number of distributions under parameterized Gaussian mixture model.
Dear R users:
I am wondering how to ask for *fixed* number of distributions under
parameterized Gaussian mixture model.
I know that em() and some related functions can predict the
parameterized Gaussian mixture model. However, there seems no
parameter to decide number of distributions to be mixed (if we known
the value in advance).
That is, assume I know the (mixed)data is from 3 different
2006 Nov 27
0
EM algorithm for truncated multivariate mixture of normals
I couldn't find a direct answer in CRAN to this question, so I'm asking
with some trepidation. I have a multivariate dataset (data.frame) with
columns that can be expressed as a set of mixed normals (at least I think)
and need to impute values that have constraints (truncated mixture of
normals where the values cannot be below zero). If there isn't a package
that can do this, is there
2009 May 21
1
em algorithm mixture of multivariate normals
Hi,
I would like to know if it is possible to have a "R code" to estimate the
parameters of a mixture of bivariate (or multivariate) normals via EM
Algorithm. I tried to write it, but in the estimation of the matrix of
variance and covariance, i have some problems. I generate two bidimensional
vectors both from different distribution with their own vector means and
variance and
2008 Aug 12
0
KS Test for Mixture of Distributions
Hi all,
How can we use ks.test() to evaluate
goodness of fit of mixtures of distributions?
For example I have the following dataset:
> x
[1] 176.1 176.8 259.6 171.6 90.0 234.3 145.7 113.7 105.9 176.2 168.9 136.1
[13] 109.2 110.3 164.3 117.7 131.3 163.7 200.4 196.4 196.2 168.6 190.4 127.5
[25] 136.0 114.2 112.0 91.9 333.4 295.5 172.0 293.3 91.7 289.7 118.8 55.1
[37] 161.9 233.9 197.7
2007 Sep 07
1
How to obtain parameters of a mixture model of two lognormal distributions
Dear List,
I have read that a lognormal mixture model having a pdf of the form
f(x)=w1*f1(x)+(1-w1)*f2(x) fits most data sets quite well, where f1
and f2 are lognormal distributions.
Any pointers on how to create a function that would produce the 5
parameters of f(x) would be greatly appreciated.
> version
_
platform i386-pc-mingw32
arch i386
os
2009 Jun 13
1
Fitting Mixture of Non-Central Student's t Distributions
Dear all,
I am attempting to model some one-dimensional data using a mixture model
of non-central Student's t distributions. However, I haven't been able
to find any R package that provides this functionality.
Could there be a way to "manipulate" the EM algorithms from the mixdist
or mixtools package to fit the model, or do you have any other
suggestions?
If anyone could help
2009 Jun 09
0
quantile of a mixture of bivriate normal distributions
Hi,
Does anyone know how to compute the quantile of a mixture of four
bivariate normal distriutions?
Many thanks!
Hannah
[[alternative HTML version deleted]]
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
2013 Mar 18
2
Fit a mixture of lognormal and normal distributions
Hello
I am trying to find an automated way of fitting a mixture of normal and log-normal distributions to data which is clearly bimodal.
Here's a simulated example:
x.1<-rnorm(6000, 2.4, 0.6)x.2<-rlnorm(10000, 1.3,0.1)X<-c(x.1, x.2)
hist(X,100,freq=FALSE, ylim=c(0,1.5))lines(density(x.1), lty=2, lwd=2)lines(density(x.2), lty=2, lwd=2)lines(density(X), lty=4)
Currently i am using
2001 Aug 28
2
fitting a mixture of distributions with optim and max log likelihood ?
hi
Suppose I have a mixture of 2 distributions generated by
rtwonormals <- function(npnt,m1,s1,m2,s2,p2){
rv<-vector(npnt,mode="numeric")
for( i in seq(1:npnt)){
if(runif(1,0,1)<=p2){
rv[i]<-rnorm(1,m2,s2)
}
else{
rv[i]<-rnorm(1,m1,s1)
}
}
return(rv)
}
x <- rtwonormals(50000,0,100,500,500,0.05)
#and I try to fit these with (based on thread: [R]
2009 Nov 09
1
Quickly generate all possible combinations of 2 groups
Hi all,
I suspect the answer to this query will be the tongue-in-cheek "use a
quantum computer", but I thought my understanding might be
sufficiently limited that I'm missing a simpler option.
I'm looking for a way to cycle through all possible combinations of 2
groups of data. For 10 data points, that's 2^10 combinations, for 20
data points it's 2^20, etc. combn() from
2001 Sep 03
8
mixture distributions
Dear List,
I am looking for a possibility to fit a mixture model under R using
maximum likelihood estimation.
Venables and Ripley describe a solution working under S+ (in MASS, 3. ed.,
p. 263) which requires the D system function and deriv3. This solution does not
seem to be portable to R or at least I do not realise how.
Is there anyone who
a) knows how one could make the MASS-method run under
2003 Nov 19
0
'nor1mix' for 1-dimensional normal mixture distributions
I have been authoring a very small R package on CRAN, named
"normix" which implements an S3 class "norMix" has plot and
print methods; further, E[X] and Var[X] methods, random number
generation ("r") and density evaluation.
It also provides the 16 "Marron-Wand densities" (known in the (1d)
density estimation business).
Erik J?rgensen has provided
2003 Nov 19
0
'nor1mix' for 1-dimensional normal mixture distributions
I have been authoring a very small R package on CRAN, named
"normix" which implements an S3 class "norMix" has plot and
print methods; further, E[X] and Var[X] methods, random number
generation ("r") and density evaluation.
It also provides the 16 "Marron-Wand densities" (known in the (1d)
density estimation business).
Erik J?rgensen has provided
2017 Jul 02
0
package to fit mixtures of student-t distributions
Thanks Ranjan,
that provides exactly what I need.
I also got a more elaborate answer on stackoverflow (after the same question got rejected form cross validated?) with a running example for this package:
https://stackoverflow.com/questions/44825529/package-to-fit-mixtures-of-student-t-distributions/44827220#44827220