Displaying 20 results from an estimated 7000 matches similar to: "Mixture of Normals with Large Data"
2004 Nov 18
1
gibbs sampling for mixture of normals
hi
i'm looking for a gibbs sampling algorithm for R for the case of mixture of K
normals, and in particular for the case of bivariate normals.
i'd be grateful if anyone could send its own R-routine, at least for the
univariate case.
thank you in advance
matteo
2011 Apr 04
1
Difference in mixture normals and one density
Hello,
I am trying to find out if R can do the following:
I have a mixture of normals say f = 0.2*Normal(2, 5) + 0.8*Normal(3,2)
How do I find the difference in the densities at any particular point of f
and at Normal(2,5)?
-- 
Thanks,
Jim.
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2009 Nov 25
1
fitting mixture of normals distribution to asset return data
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2002 Oct 22
5
Mixture of Univariate Normals
Dear list,
Can anyone provide a package or code for estimating the parameters of a
mixture of c (c >=2) univariate normal distributions?
I've tried the algorithm provided by Venables & Ripley (1999) p 263, for
the mixture of two normal, but I don't find the "ms" function in R. I've
used nls instead, but I'm not sure if it works the same.
The data I have is very
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
2007 Feb 23
3
mixture of 2 normals - starting values
Hi,
I have a problem of estimating a mixture of two normal distributions.  I
need to find the starting points automatically, since this is a part of a
larger piece of image processing code.
I found the mix2normal1 function in VGAM package that mentions a method of
finding starting values for mu1 and mu2 but refers the reader to a book by
Everitt and Hand.  Unfortunately, I do not have an easy
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 12
1
Mixture of normals
Can anyone send me the R code for fitting a mixture of normal distributions.
Or in fact any'combination' of mixtures of distributions. I looke dta mix
but it is still not clear to me.
Jim
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2006 Feb 08
1
Mixture normal distribution
Dear R helper,
I hope that u can help me to sort out my problem
because I sent an E-mail last night to R-list but I
have not receive any help and at the same time I think
this problem is not so hard.
I have used the following functions before 
> K<-10
> prime<-c(2,3,5,7,11,13,17)
> UN<-seq(1:K)%*%t(sqrt(prime))
> U1<-UN-as.integer(UN)
> U<-matrix(qnorm(U1),K,7)
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
2005 Oct 11
0
random effects are mixture of normals
Dear All,
I wonder if there is an R package to estimate the generalized linear mixed models but with a random effects having  a mixture of normals as a prior distributinon ..
Thank you,
Abderrahim
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2007 May 25
0
Scale mixture of normals
Dear Friends,
Is there an R package which implements regression
models with error distributions following a scale
mixture of normals? 
Thanks
Anup
2009 Apr 30
1
finite mixture model (2-component Weibull): plotting Weibull components?
Dear Knowledgeable R Community Members,
 
 Please excuse my ignorance, I apologize in advance if this is an easy question, but I am a bit stumped and could use a little guidance.
 
 I have a finite mixture modeling problem -- for example, a 2-component Weibull mixture -- where the components have a large overlap, and 
 I am trying to adapt the "mclust" package which concern to normal
2006 Dec 25
1
Bayesian data mining
Hi, I need a help to know whether I can perform the following in R:
I have a set of observations (Ns) and each observation is drawn from a 
poisson distribution with an unkown mean, lambda. The set of lambdas in 
their turn are drawn from a common prior distribution which is supposed to 
be a a mixture of two gamma distributions.
Is there a way to determine the poisson means in R, given the Ns and
2005 Mar 23
4
sampling from a mixture distribution
Dear R users,
I would like to sample from a mixture distribution p1*f(x1)+p2*f(x2). I 
usually sample variates from both distributions and weight them with their 
respective probabilities, but someone told me that was wrong. What is the 
correct way?
Vumani
2006 Mar 21
1
Simulate Mixture Model data
Dear R Users??
I woould like to generate mixture model data.
I try two type method as followings two method, can anyone tell me which is right? or  better?
1. generate two vectors data y1 and y2 from f1 and f2 seperately, and calculate y=alpha1*y1+alpha2*y2,
2. generate prob=unif(1), if prob <alpha1 y=y1, else y=y2. 
Can anyone give me some idea?
Thanks so much!	
Goeland
goeland at
2011 Apr 22
1
How to generate normal mixture random variables with given covariance function
Dear All,
Suppose Z_i, i=1,...,m are marginally identically distributed as a two normal mixture p0*N(0,1) + (1-p0) *N( miu_i, 1) where miu_i are  identically distributed according to a mixture and I have  generated Z_i one by one . 
Now suppose these m random variables are jointly m-dimensional normal with correlation matrix M= (m_ij).
How to proceed next or how to start correctly ? 
Question:  
2013 Mar 30
1
normal mixture EM not working?
Hi,
I am currently working on fitting a mixture density to financial data.
I have the following data:
http://s000.tinyupload.com/?file_id=00083355432555420222
I want to fit a mixture density of two normal distributions.
I have the formula:
f(l)=πϕ(l;μ1,σ21)+(1−π)ϕ(l;μ2,σ22)
my R code is:
normalmix<-normalmixEM(dat,k=2,fast=TRUE)
pi<-normalmix$lambda[1]
    mu1<-normalmix$mu[1]
2009 Jul 26
1
normal mixture model
Hi, All,
I want to fit a normal mixture model. Which package in R is best for this? I
was using the package 'mixdist', but I need to group the data into groups
before fitting model, and different groupings seem to lead to different
results. What other package can I use which is stable? And are there
packages that can automatically determine the number of components?
Thank you,
Cindy
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