Displaying 20 results from an estimated 2000 matches similar to: "Probit regression with limited parameter space"
2010 Oct 01
1
Place constrictions on parameters when using Optim and MaxLik
Hi R users,
I am trying to restrct the range of two of the parameters in a maximization
problem. Both parameters should be between -1 and 1. As far as I know, if
I choose the estimation method ="L-BFGS-B" under Optim, I can restrict the
parameter space. However, the "L-BFGS-B" always require finite values of
the loglik function and cannot get around of the problem if an
2007 Nov 15
3
not R question : alternative to logistic regression
I was just curious if anyone knew of an alternative model to logistic regression where the probabilities seems pretty linear to the predictor rather than having that S shape that probit and logit assume.
Maybe there is there some kind of other GLM that could accomplish that. Any textbook references or suggestions
are appreciated. I have most of the texts but if someone knows of a text that talks
2010 Oct 15
1
Problem using BRugs
Hi R users,
I am trying to call openbugs from R. And I got the following error message:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
model is syntactically correct
expected the collection operator c error pos 8 (error on line 1)
variable ww is not defined in model or in data set
[1] "C:\\DOCUME~1\\maomao\\LOCALS~1\\Temp\\RtmpqJk9R3/inits1.txt"
2012 Oct 11
2
model selection with spg and AIC (or, convert list to fitted model object)
Dear R Help,
I have two nested negative log-likelihood functions that I am optimizing
with the spg function [BB package]. I would like to perform model
selection on these two objective functions using AIC (and possibly
anova() too). However, the spg() function returns a list and I need a
fitted model object for AIC(), ICtab() [bbmle package], or anova().
How can I perform AIC-based model
2010 Sep 14
2
Can I monitor the iterative/convergence process while using Optim or MaxLik?
Hi R-helpers,
Is it possible that I have the estimates from each step/iteration shown on
the computer screen in order to monitor the process while I am using Optim
or MaxLik?
Thanks for your help.
Maomao
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2005 Jul 25
5
passing formula arguments cv.glm
I am trying to write a wrapper for the last example in help(cv.glm) that
deals with leave-one-out-cross-validation (LOOCV) for a logistic model.
This wrapper will be used as part of a bigger program.
Here is my wrapper funtion :
logistic.LOOCV.err <- function( formu=NULL, data=NULL ){
cost.fn <- function(cl, pred) mean( abs(cl-pred) > 0.5 )
glmfit <- glm(
2011 Mar 20
3
How to draw a map of Europe?
Hi R users,
I need to draw a map of select European countries with country names shown
on the map. Does anyone know how to do this in R?
Also, is it possible to draw a historical map of European countries using R?
Thanks a lot for your help.
Maomao
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2012 Jun 19
1
Error when trying to update cpglm model
Dear all,
I've been having problems running update() to re-fit a cpglm model inside a function (as in the code below). The solution is probably simple, but I'm stuck. If anyone could help, I'd greatly appreciate it.
Regards,
Rubem
## R code
library(cplm)
## Data simulation
period<-factor(1:4)
herd<-factor(1:50)
2010 Jan 10
1
scatterplot matrix with ggplot2
#I would like to use the below data to make a scatter plot matrix with
#code similar to that below the data
#conceptually this is the right approach I think
#thanks in advance
melt.gg <- structure(list(stream = c("Bonham Lower", "Bonham Lower",
"Bonham Lower",
"Bonham Lower", "Bonham Lower", "Bonham Lower", "Bonham Lower",
2003 Apr 02
19
Combining the components of a character vector
Dear Help,
Suppose I have a character vector.
x <- c("Bob", "loves", "Sally")
I want to combine it into a single string: "Bob loves Sally" .
paste(x) yields:
paste(x)
[1] "Bob" "loves" "Sally"
The following function combines the character vector into a string in the
way that I want, but it seems somewhat inelegant.
2009 Mar 11
3
Converting a dataframe to a matrix
If I have a dataframe which is organized like this:
name color likes?
1 sally red 0
2 sally blue 1
3 sally green 1
4 jake red 0
5 jake blue 1
6 jake green 1
7 tom red 1
8 tom blue 0
9 tom green 0
And I want to create a matrix in the form:
red blue green
sally 0 1 1
jake 0 1 1
tom 1 0 0
Are there any built-in
2009 Feb 01
2
Extracting Coefficients and Such from mle2 Output
The mle2 function (bbmle library) gives an example something like the
following in its help page. How do I access the coefficients, standard
errors, etc in the summary of "a"?
> x <- 0:10
> y <- c(26, 17, 13, 12, 20, 5, 9, 8, 5, 4, 8)
> LL <- function(ymax=15, xhalf=6)
+ -sum(stats::dpois(y, lambda=ymax/(1+x/xhalf), log=TRUE))
> a <- mle2(LL,
2016 Apr 20
2
Data reshaping with conditions
Dear All,
I am trying to reshape the data with some conditions. A small part of the
data looks like below. Like this there will be more data with repeating ID.
Count id name type
117 335 sally A
19 335 sally A
167 335 sally B
18 340 susan A
56 340 susan A
22 340 susan B
53 340 susan B
135 351 lee A
114 351 lee A
84 351 lee A
80 351 lee A
19 351 lee A
8 351 lee A
21 351 lee A
88 351 lee B
111 351
2016 Apr 20
0
Data reshaping with conditions
Hi sri,
As your problem involves a few logical steps, I found it easier to
approach it in a stepwise way. Perhaps there are more elegant ways to
accomplish this.
svdat<-read.table(text="Count id name type
117 335 sally A
19 335 sally A
167 335 sally B
18 340 susan A
56 340 susan A
22 340 susan B
53 340 susan B
135 351 lee A
114 351 lee A
84 351 lee A
80 351 lee A
19 351 lee A
8 351 lee A
2010 Jul 31
3
Installing iTunes on Linux Mint Isadora 9
Hi all,
I have downloaded the latest version of wine in order to run iTunes but when I tried to execute the program here is what I get :
cd /home/sally/Documents
$ wine iTunes64Setup.exe
Trying to load PE image for unsupported architecture (AMD-64)
err:process:create_process starting 64-bit process L"Z:\\home\\sally\\Documents\\iTunes64Setup.exe" not supported on this platform
wine:
2011 Dec 01
1
Estimation of AR(1) Model with Markov Switching
Dear R users,
I have been trying to obtain the MLE of the following model
state 0: y_t = 2 + 0.5 * y_{t-1} + e_t
state 1: y_t = 0.5 + 0.9 * y_{t-1} + e_t
where e_t ~ iidN(0,1)
transition probability between states is 0.2
I've generated some fake data and tried to estimate the parameters using the
constrOptim() function but I can't get sensible answers using it. I've tried
using
2009 Nov 23
4
Check if string has all alphabets or numbers
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2012 Jan 12
2
Function accepted by optim but not mle2 (?)
Dear Sir/ Madam,
I'm having trouble de-bugging the following - which works perfectly
well with optim or optimx - but not with mle2.
I'd be really grateful if someone could show me what is wrong. Many
thanks in advance. JSC:
gompertz<- function (x,t=data)
{
a3<-x[1]
b3<-x[2]
shift<-data[1]
h.t<-a3*exp(b3*(t-shift))
2008 Jul 21
1
Control parameter of the optim( ): parscale
Hi everybody,
I am using the L-BFGS-B method of the mle2() function to estimate the values
of 6 parameters. mle2 uses the methods implemented in optim. As I got it
from the descriptions available online, one can use the parscale
parameter to tell R somehow what the values of the estimated parameters
should be . . .
Could somebody please help me understand what one has to do actually with
the
2016 Apr 21
2
Data reshaping with conditions
Hi Jim,
Thanks for your time. But somehow this code did not help me to achieve my
expected output.
Problems: 1) x, y are coming as logical rather than values as I mentioned
in my post
2) The values that I get for Max A and Max B not correct
3) It looks like a pretty big data, but I just need to
concatenate the values with a comma, the final output will be a character