Displaying 20 results from an estimated 2000 matches similar to: "Difference in mixture normals and one density"
2003 Apr 10
6
How to plot several graphs in a single 2-D figure?
Hi, R-listers
I tried to plot several graphs in a sigle x-y coordinate settings, like the
following:
|(y) s
| ****** s
| ***** s
| sssssssssssssssssss
|_______________________________(x)
where "*" and "s" denote two diffrent plots.
However, when I used
plot(data1); % data1 is the data points of "*"
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
[[alternative HTML version deleted]]
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
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
2009 Jun 22
1
The gradient of a multivariate normal density with respect to its parameters
Does anybody know of a function that implements the derivative (gradient) of
the multivariate normal density with respect to the *parameters*?
It?s easy enough to implement myself, but I?d like to avoid reinventing the
wheel (with some bugs) if possible. Here?s a simple example of the result
I?d like, using numerical differentiation:
library(mvtnorm)
library(numDeriv)
f=function(pars, xx, yy)
2003 Jan 27
1
rmultinom() -- how \\ via own C code?
I've had a need for multinomial "random number generation"
occasionally. And other people too.
The following code is currently in the
(very small ``not very high importance'') CRAN package normix
--- which I will rename to "nor1mix" very seen because of a
``name registration'' problem
I want to add "this" (well the functionality) to a
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
2007 Aug 04
2
Mixture of Normals with Large Data
All:
I am trying to fit a mixture of 2 normals with > 110 million observations. I
am running R 2.5.1 on a box with 1gb RAM running 32-bit windows and I
continue to run out of memory. Does anyone have any suggestions.
Thanks so much,
Tim
[[alternative HTML version deleted]]
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
2003 Jul 17
3
univariate normal mixtures
Hello,
I have a concrete statistical question:
I have a sample of an univariate mixture of an unknown number (k) of
normal distributions, each time with an unknown mean `m_i' and a
standard deviation `k * m_i', where k is known factor constant for all
the normal distributions. (The `i' is a subscript.)
Is there a function in R that can estimate the number of normal
distributions k
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
2011 Mar 20
3
Part of a density plot
Suupose I have
y <- rbeta(10000, 2, 5)
and I only want to see only the density plot from x = 0 to x = 1
How do I do this?
--
Thanks,
Jim.
[[alternative HTML version deleted]]
2011 Mar 21
2
Part of density plot not showing up
I am doing a histogram with 2 superimposed densities. However, the density
of one of the graphs is not coming out..its being erased.. Any ideas on how
to fix this problem?
--
Thanks,
Jim.
[[alternative HTML version deleted]]
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
[[alternative HTML version deleted]]
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 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
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
2006 Jun 15
2
Standard Deviation Distribution
I'm having trouble with the standard deviation distribution
as shown on http://mathworld.wolfram.com/StandardDeviationDistribution.html .
(Eric Weisstein references Kenney and Keeping 1951, which I can't check.)
I believe the graphs they show, but when I code the function in R, according to the listed formula,
I get very different graphs.
Would someone please point out my error or tell