[R] mle from stats4

2009-10-06 Thread Stephen Collins
I am using mle as a wrapper from optim( ).  How would I extract the 
convergence code, to know that optim( ) converged properly?

Thanks,
 
 
Stephen Collins, MPP | Analyst
Global Strategy | Aon Benfield

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Using linear formula inside MLE

2009-09-28 Thread Stephen Collins
Say I have a formula Y ~ 1 + X, where X is a categorical variable.  A 
previous thread showed how to evaluate this model using the mle package 
from stats4 (see below).  But, the user had to create the data matrix, 
X, including the column of one's for the regression constant.  Is there a 
way to nest the linear formula in the code below, so the data matrix 
doesn't explicitly have to be created by the user?

Y - c(0,0,1,0,0,1,1,0,0,0,0,1,1,0,1,1,0,1,1,0,1) 
X - 
cbind(matrix(1,21,1),matrix(c(-48.5,24.4,82.8,-24.6,-31.6,91.0,52.1,-87.7,-17.0,-51.5,
-90.7,65.5,-44.0,-7.0,51.6,32.4,-61.8,34.0,27.9,-72.9,49.9), 21,1)) 

log.lo.like - function(beta,Y,X) { 
Fbetax - 1/(1+exp(-beta%*%t(X))) 
loglbeta - -log(prod(Fbetax^Y*(1-Fbetax)^(1-Y))) 
} 

#Using MLE#
ll - eval(function(beta0=0,beta1=0) 
 log.lo.like (c(beta0,beta1),Y,X),
   list(X=X,Y=Y))


summary(mle(ll)) 
Comparison using glm#
glm(Y~X-1,family=binomial) 


Thanks, 
 
 
Stephen Collins, MPP | Analyst
Global Strategy | Aon Benfield
 
[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] optim() question

2009-05-26 Thread Stephen Collins
I've seen with other software the capability for the optimizer to switch 
algorithms if it is not making progress between iterations.  Is this 
capability available in optim()?

Thanks,
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] mle() question

2009-05-22 Thread Stephen Collins
Is there a way to code the mle() function in library stats4 such that it 
switches optimizing methods midstream (i.e. BFGS to Newton and back to 
BFGS, etc.)?

Thanks,
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] loglik and arima()

2009-02-10 Thread Stephen Collins
All - 

I am evaluating an arima(2,1,3) and arima(3,1,3) and notice the 
log-likelihood of the restricted model is higher than the log-likelihood 
of the unrestricted. 

Since these are nested models, I thought the unrestricted model would have 
a log-likelihood at least as large as that of the restricted model.  Am I 
interpreting the loglik output incorrectly?

Regards,

   
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting
200 East Randolph, Suite 900, Chicago, IL
Tel: 312-381-2578 | Fax: 312-381-0136
Email: stephen_coll...@aon.com
 
Aon Consulting selected by the readers of Business Insurance as the “Best 
Employee Benefit Consulting Firm” in 2006, 2007, and 2008
 
NOTE: The information contained in this transmission, including any 
attachment(s) is only for the use of the intended individual(s) or entity, 
and may contain information that is privileged and confidential. If the 
reader of this message is not an intended recipient, you are hereby 
notified that any dissemination, distribution, disclosure, or copying of 
this information is unauthorized and strictly prohibited. If you have 
received this communication in error, please contact the sender 
immediately by reply email and destroy all copies of the original message.
 

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Categorical Variables and glm()

2009-01-23 Thread Stephen Collins
When including categorical variables in a regression, the default in R is 
to set the first level as the base.  Is there an option to specify a 
different level as the base? 

Regards, 
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Viewing code

2008-12-24 Thread Stephen Collins
How do you view the code for a built-in R command (i.e.,  if I want to see 
what R is doing when I run a glm() statement)?

Regards,

Stephen

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] How fast of a desktop can I buy?

2008-11-12 Thread Stephen Collins
I currently run simulations on an IBM x31 Thinkpad (laptop), with an Intel 
Pentium M, 1.3GHz processor.  I am planning to buy a desktop to help speed 
up my work, but I am wondering if R is compatible with some of the newer 
technology that has come to market (i.e., Intel Core 2 Duo, Quad Core 
processors, 64-bit operating systems). 

Does anyone know the threshold or limit on R's capabilities, where buying 
more computer ceases to impact the speed at which R executes its task at 
hand?   I need to know what type of processor, how much memory, cache, 
etc., I should be looking for in a desktop.

Regards, 
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting
200 East Randolph, Suite 900, Chicago, IL
Tel: 312-381-2578 | Fax: 312-381-0136
Email: [EMAIL PROTECTED]
 
Aon Consulting selected by the readers of Business Insurance as the “Best 
Employee Benefit Consulting Firm” in 2006, 2007, and 2008
 
NOTE: The information contained in this transmission, including any 
attachment(s) is only for the use of the intended individual(s) or entity, 
and may contain information that is privileged and confidential. If the 
reader of this message is not an intended recipient, you are hereby 
notified that any dissemination, distribution, disclosure, or copying of 
this information is unauthorized and strictly prohibited. If you have 
received this communication in error, please contact the sender 
immediately by reply email and destroy all copies of the original message.
 

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Vectorizing sample()

2008-11-07 Thread Stephen Collins
I am simulating sickness among a group of families.  Part of the task is 
to randomly draw who in the family will be sick, randomly drawing from 
family ID's where Dad =1, Mom = 2, Kid1 = 3, Kid2 = 4., etc.  My census of 
Dads is of the form shown below. 

Dad_ID  Spouse (Y=1;N=0)#Kids #People_Becoming_Sick
1   1   0   1
2   0   2   2
3   1   0   2
4   1   3   3
...

The end output needed is if 3 people in a family are to be sick, was it 
the dad and two kids, with random family ID's =  {1,3,4}, or the mom, dad, 
and one kid,  with random family ID's =  {2,1,4}, etc..  The complication 
is that length of the family ID's to choose from and the associated 
sampling probabilities -- changes with each family.   I could loop through 
the Dads, from i in 1:nrow(census), but is there a way I could vectorize 
sample() to get at the same objective? 

My attempts to use the apply-based functions have dead ended.  Other ideas 
to vectorize this problem are warmly welcomed.



Regards,
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting
200 East Randolph, Suite 900, Chicago, IL
Tel: 312-381-2578 | Fax: 312-381-0136
Email: [EMAIL PROTECTED]
 
Aon Consulting selected by the readers of Business Insurance as the “Best 
Employee Benefit Consulting Firm” in 2006, 2007, and 2008
 
NOTE: The information contained in this transmission, including any 
attachment(s) is only for the use of the intended individual(s) or entity, 
and may contain information that is privileged and confidential. If the 
reader of this message is not an intended recipient, you are hereby 
notified that any dissemination, distribution, disclosure, or copying of 
this information is unauthorized and strictly prohibited. If you have 
received this communication in error, please contact the sender 
immediately by reply email and destroy all copies of the original message.
 

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.


[R] Two overlaid density plots - Does order matter?

2008-09-25 Thread Stephen Collins
In the following code, the only difference between the two plots is the 
order the variables are plotted.  In this case, the plot of cdata.den in 
plot #1 is different from its plot in #2. Specifically, cdata.den spans 
the x-axis from -5 to 30 in plot #1 and from 0 to 20 in plot #2. Does 
anyone understand why these two plots do not yield the same result? 

#Make density objects
pre.den- density(
preclaims[preclaims[,7]cc1  preclaims[,7]cc2,7],
from = cc1,
to = cc2)
cdata.den-density(cdata,from=cc1,to=cc2)

#Plot No. 1
x11()
plot(cdata.den,col=1)
lines(pre.den,col=2)

#Plot No. 2
plot(pre.den,col=2)
lines(cdata.den,col = 1)

 Regards,
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting
200 East Randolph, Suite 900, Chicago, IL
Tel: 312-381-2578 | Fax: 312-381-0136
Email: [EMAIL PROTECTED]
 

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.