Displaying 20 results from an estimated 300 matches similar to: "Problem with optim()"
2010 Oct 13
5
Poisson Regression
Hello everyone,
I wanted to ask if there is an R-package to fit the following Poisson
regression model
log(\lambda_{ijk}) = \phi_{i} + \alpha_{j} + \beta_{k}
i=1,\cdots,N (subjects)
j=0,1 (two levels)
k=0,1 (two levels)
treating the \phi_{i} as nuinsance parameters.
Thank you very much
--
-Tony
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2005 Dec 01
1
Kalman Smoothing - time-variant parameters (sspir)
Dear R-brains,
I'm rather new to state-space models and would benefit from the extra
confidence in using the excellent package sspir.
In a one-factor model, If I am trying to do a simple regression where
I assume the intercept is constant and the 'Beta' is changing, how do
I do that? How do i Initialize the filter (i.e. what is appropriate to
set m0, and C0 for the example below)?
2006 Apr 29
1
SSPIR problem
I am having a problem with the package SSPIR. The code below
illustrates it. I keep getting the message: "Error in y - f :
non-conformable arrays."
I tried to tweak the code below in many different ways, for example,
substituting rbind for cbind, and sometimes I get a different error
message, but I could not find a variation of this code that would
work.
Any help will be greatly
2007 Aug 14
2
State Space Modelling
Hey all,
I am trying to work under a State Space form, but I didn't get the help
exactly.
Have anyone eles used this functions?
I was used to work with S-PLUS, but I have some codes I need to adpt.
Thanks alot,
Bernardo
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2010 Nov 14
5
kalman filter
Hello,
I would like use Kalman filter for estimating parameters of a stochastic
model. I have developed the state space model but I don’t know the correct
way use Kalman filter for parameter estimation. Has anybody experience in
work with Kalman filter in R.
I don’t know the correct function. Maybe it is
- KalmanLike; but what is the correct Input?
- tsmooth?
-
2010 Aug 24
0
Using kfilter in package sspir - dimensions do not agree
I'm currently running into a little trouble with the kfilter method,
and would love some clarification if you are able to offer it. When
trying to run kfilter, I've been running into errors that seem to
result from having mismatched dimensions. Specifically, the dimension
of my observations is 2, while the dimension of the state space is 4.
In the filterstep function (file sspir_kfs.R),
2007 Nov 15
3
kalman filter estimation
Hi,
Following convention below:
y(t) = Ax(t)+Bu(t)+eps(t) # observation eq
x(t) = Cx(t-1)+Du(t)+eta(t) # state eq
I modified the following routine (which I copied from: http://www.stat.pitt.edu/stoffer/tsa2/Rcode/Kall.R) to accommodate u(t), an exogenous input to the system.
for (i in 2:N){
xp[[i]]=C%*%xf[[i-1]]
Pp[[i]]=C%*%Pf[[i-1]]%*%t(C)+Q
siginv=A[[i]]%*%Pp[[i]]%*%t(A[[i]])+R
2011 Jan 03
1
Greetings. I have a question with mixed beta regression model in nlme.
*Dear R-help:
My name is Rodrigo and I have a question with nlme package
in R to fit a mixed beta regression model. The details of the model are:
Suppose that:*
*j in {1, ..., J}* *(level 1)*
*i in {1, ..., n_j}* *(level 2)*
*y_{ij} ~ Beta(mu_{ij} * phi_{ij}; (1 - mu_{ij}) * phi_{ij})
y_{ij} = mu_{ij} + w_{ij}
*
*with*
*logit(mu_{ij}) = Beta_{0i} + Beta_{1i} * x1_{ij} + b2 * x2_{ij}
2011 Jan 03
0
Greetings. I have a question with mixed beta regression model in nlme (corrected version).
*Dear R-help:
My name is Rodrigo and I have a question with nlme package
in R to fit a mixed beta regression model. I'm so sorry. In the last
email, I forgot to say that W is also a unknown parameter in the mixed
beta regression model. In any case, here I send you the correct formulation.
**
Suppose that:*
*j in {1, ..., J}* *(level 1)*
*i in {1, ..., n_j}* *(level 2)*
*y_{ij} ~
2009 Sep 11
3
State Space models in R
Hello everybody,
I am writing a review paper about State Space models in R, and I would
like to cover as many packages as I reasonably can.
So far I am familiar with the following tools to deal with SS models:
* StructTS, Kalman* (in stats)
* packages dse[1-2]
* package sspir
* package dlm
I would like to have some input from users who work with SS models:
are there any other packages for SS
2005 Dec 14
1
Kalman Filter Forecast using 'SSPIR'
Dear R Users,
I am new to state-space modeling. I am using SSPIR
package for Kalman Filter. I have a data set containing one dependent
variable and 7 independent variables with 250 data points. I want to use
Kalman Filter for forecast the future values of the dependent variable
using a multiple regression framework. I have used ssm function to
produce the state space (SS)
2007 Mar 22
2
dynamic linear models in R
Hi all,
I've just started working my way through Mike West and Jeff Harrison's
_Bayesian Forecasting and Dynamic Models_, and I was wondering if
there were any publically-available packages to handle dynamic linear
models, as they describe.
I found the "dynlm" package, but either I don't yet understand what's
going on or that package uses a different sense of the phrase
2006 Jun 15
1
SSPIR problem
Dear R-Users,
I'm using SSPIR package for a spatio-temporal application.
Is it possible to modify the structure of the involved matrixes (Fmat,
Gmat, Vmat,Wmat)?
I want to create a model like this
#y(t)=k*theta(t)+epsilon(t)
#theta(t)=h*theta(t-1)+eta(t)
#epsilon(t) N(0,V) V=sigma2*I
#eta(t) N(0,W) W=sigma2_eta
where the state variable theta has dimension 1(p=1) and at
2006 Nov 01
1
did my searching but still couldn't find anything for bayesian dlm
I familarized myelf with kalmanlike and structts which are approaches
for building and estimating ( and forecasting ) state space models ( or
the equivalent arima models ).
back in 2003, gavin simpson wrote an email describing the west and
harrison apprach to estimate state space models and asked if anything
was out there for
using that approach. the goals of this approach are the same as kalman
2008 Feb 26
2
Kalman Filter
Hi
My name is Vladimir Samaj. I am a student of Univerzity of Zilina. I am
trying to implement Kalman Filter into my school work. I have some problems
with understanding of R version of Kalman Filter in package stats( functions
KalmanLike, KalmanRun, KalmanSmooth,KalmanForecast).
1) Can you tell me how are you seting the initial values of state vector in
Kalman Filter? Are you using some method?
2005 Jul 16
2
topical guide to R packages
I would like to see R packages arranged by topic. CRAN
Task Views are at
http://lib.stat.cmu.edu/R/CRAN/src/contrib/Views/ ,
but I'd like something more detailed. For example, the
IMSL Fortran library, version 4 is easy to navigate
and has procedures arranged according to following
topics:
Basic Statistics
Regression
Correlation
Analysis of Variance
Categorical and Discrete
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
2005 Dec 30
1
GLARMA
Hello,
I am a new R user and I need R code for GLARMA.
I will be really thankful if you help me.
Yours sincerely,
2007 Dec 05
2
kalman filter random walk
Hi,
I'm trying to use the kalman filter to estimate the variable drift of a
random walk, given that I have a vector of time series data. Anyone have
any thoughts on how to do this in R?
Thanks,
Alex
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2008 Mar 10
1
state space model for poisson distribution
Hi Rers,
I have a poission time series model with 5 parameters. I just wanted to remove two of the lag on response in the model and put it as a system model. I am not sure about the codes to combine these two on R. If anybody has any R example (code), please post it.
My original model: log(Y(t))~constant+b1*Y(t-1)+b2*Y(t-2)+b3*(variable1)+b4*(variable2)+e
I would like to construct a