Displaying 20 results from an estimated 900 matches similar to: "Obtaining fitted model information"
2005 Jan 13
8
Installing R on Xandros 3.0
Dear List,
After obtaining a second-hand PC and because XP costs too much, I installed Xandros 3.0 (based on Debian) but pretty easy to use if migrating from WinXP.
Does anyone know how to install R on this OS?
Thank you for your time,
Tom Volscho
************************************
Thomas W. Volscho
Graduate Student
Dept. of Sociology U-2068
University of Connecticut
Storrs, CT 06269
2004 Nov 18
4
Enormous Datasets
Dear List,
I have some projects where I use enormous datasets. For instance, the 5% PUMS microdata from the Census Bureau. After deleting cases I may have a dataset with 7 million+ rows and 50+ columns. Will R handle a datafile of this size? If so, how?
Thank you in advance,
Tom Volscho
************************************
Thomas W. Volscho
Graduate Student
Dept. of Sociology U-2068
2004 Dec 12
12
switching to Linux, suggestions?
Dear List,
I have acquired a new desktop and wanted to put a free OS on it. I am trying Fedora Core 1, but not sure what the best Linux OS is for using R 2.0.1?
Thank you in advance for your input,
Tom Volscho
************************************
Thomas W. Volscho
Graduate Student
Dept. of Sociology U-2068
University of Connecticut
Storrs, CT 06269
Phone: (860) 486-3882
2005 Nov 17
3
loess: choose span to minimize AIC?
Is there an R implementation of a scheme for automatic smoothing
parameter selection with loess, e.g., by minimizing one of the AIC/GCV
statistics discussed by Hurvich, Simonoff & Tsai (1998)?
Below is a function that calculates the relevant values of AICC,
AICC1 and GCV--- I think, because I to guess from the names of the
components returned in a loess object.
I guess I could use
2012 Apr 05
4
Appropriate method for sharing data across functions
In trying to streamline various optimization functions, I would like to have a scratch pad
of working data that is shared across a number of functions. These can be called from
different levels within some wrapper functions for maximum likelihood and other such
computations. I'm sure there are other applications that could benefit from this.
Below are two approaches. One uses the <<-
2008 Aug 20
3
bug in lme4?
Dear all,
I found a problem with 'lme4'. Basically, once you load the package 'aod' (Analysis of Overdispersed Data), the functions 'lmer' and 'glmer' don't work anymore:
library(lme4)
(fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy))
(gm1 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd),
family = binomial, data
2013 Apr 15
1
Optimisation and NaN Errors using clm() and clmm()
Dear List,
I am using both the clm() and clmm() functions from the R package
'ordinal'.
I am fitting an ordinal dependent variable with 5 categories to 9
continuous predictors, all of which have been normalised (mean
subtracted then divided by standard deviation), using a probit link
function. From this global model I am generating a confidence set of 200
models using clm() and the
2010 Sep 15
1
optim with BFGS--what may lead to this, a strange thing happened
Dear R Users
on a self-written function for calculating maximum likelihood probability (plz
check function code at the bottom of this message), one value, wden, suddenly
jump to zero. detail info as following:
w[11]=2.14
lnw =2.37 2.90 3.76 ...
regw =1.96 1.77 1.82 ....
wden=0.182 0.178 0.179...
w[11]=2.14
lnw=2.37 2.90 3.76 ...
regw =1.96 1.77 1.82 ....
wden=0.182
2008 Mar 27
1
A faster way to compute finite-difference gradient of a scalar function of a large number of variables
Hi All,
I would like to compute the simple finite-difference approximation to the
gradient of a scalar function of a large number of variables (on the order
of 1000). Although a one-time computation using the following function
grad() is fast and simple enough, the overhead for repeated evaluation of
gradient in iterative schemes is quite significant. I was wondering whether
there are
2003 Nov 21
1
: BIC for gls models
Hi all,
I would like to know how the BIC criterion is calculated for models estimated using gls( ) function. I read in Pinheiro & Bates (2000) p84 that
BIC = -2logL + npar*log(N) (for the ML method), or
BIC = -2logLR + npar*log(N-p) (for the REML method)
but when I use any of these formulae I don't obtain the result given by R.
Thanks in advance for any help.
Eve CORDA
Office national
2003 Jul 18
3
question about formulating a nls optimization
Dear list,
I'm migrating a project from Matlab to R, and I'm
facing a relatively complicated problem for nls. My
objective function is below:
>> objFun <- function(yEx,xEx,tEx,gamma,theta,kappa){
yTh <- pdfDY(xEx,tEx,gamma,theta,kappa)
sum(log(yEx/yTh)^2)
}
The equation is yTh=P(xEx,tEx) + noise.
I collect my data in:
>> data <-
2010 Sep 07
5
question on "optim"
Hey, R users
I do not know how to describe my question. I am a new user for R and write the
following?code for a dynamic labor economics?model and use OPTIM to get
optimizations and parameter values. the following code does not work due to
the?equation:
?? wden[,i]<-dnorm((1-regw[,i])/w[5])/w[5]
where w[5]?is one of the parameters (together with vector a, b and other
elements in vector
2007 Apr 10
1
Using Sampling Weights in R
Dear List,
I have a dataset that provides sampling weights (National Survey of
Family Growth 2002). I want to produce a cross-tabulation and use the
provided sampling weights to obtain representative population estimates.
(I believe they are simply frequency weights but codebook is
uninformative).
I can reproduce results (using this data) that were reported in a recent
journal article, if I
2018 Apr 17
1
Minor glitch in optim()
Having worked with optim() and related programs for years, it surprised me
that I haven't noticed this before, but optim() is inconsistent in how it
deals with bounds constraints specified at infinity. Here's an example:
# optim-glitch-Ex.R
x0<-c(1,2,3,4)
fnt <- function(x, fscale=10){
yy <- length(x):1
val <- sum((yy*x)^2)*fscale
}
grt <- function(x, fscale=10){
nn
2012 Mar 18
1
Converting expression to a function
Previously, I've posted queries about this, and thanks to postings and messages in
response have recently had some success, to the extent that there is now a package called
nlmrt on the R-forge project https://r-forge.r-project.org/R/?group_id=395 for solving
nonlinear least squares problems that include small or zero residual problems via a
Marquardt method using a call that mirrors the nls()
2012 Feb 13
2
R's AIC values differ from published values
Using the Cement hardening data in Anderson (2008) Model Based Inference in
the Life Sciences. A Primer on Evidence, and working with the best model
which is
lm ( y ~ x1 + x2, data = cement )
the AIC value from R is
model <- lm ( formula = y ~ x1 + x2 , data =
cement )
AIC ( model )
64.312
which can be converted to AICc by adding the bias
2009 Apr 29
2
AICc
I am fitting logistic regression models, by defining my own link
function, and would like to get AICc values. Using the glm command
gives a value for AIC, but I haven't been able to get R to convert
that to AICc. Is there a code that has already been written for
this? Right now I am just putting the AIC values into an excel
spreadsheet and calculating AICc, likelihood, and AIC
2005 Oct 29
2
LaTex error when creating DVI version when compiling package
Dear Listers,
I got this message when compiling a package:
* creating pgirmess-manual.tex ... OK
* checking pgirmess-manual.text ... ERROR
LaTex errors when creating DVI version.
This typically indicates Rd problems.
The message is quite explicit but I struggled a lot before understanding
that the trouble comes from a single file "selMod.rd" among 44 topics.
Even though I have
2005 Nov 03
1
Help on model selection using AICc
Hi,
I'm fitting poisson regression models to counts of birds in
1x1 km squares using several environmental variables as predictors.
I do this in a stepwise way, using the stepAIC function. However the
resulting models appear to be overparametrized, since too much
variables were included.
I would like to know if there is the possibility of fitting models
by steps but using the AICc
2006 Dec 12
1
Calculating AICc using conditional logistic regression
I have a case-control study that I'm analysing using the conditional
logistic regression function clogit from the survival package.
I would like to calculate the AICc of the models I fit using clogit.
I have a variety of scripts that can calculate AICc for models with a
logLik method, but clogit does not appear to use this method.
Is there a way I can calculate AICc from clogit in R?
Many