Displaying 20 results from an estimated 2000 matches similar to: "Non-linear regression with latent variable"
2009 Oct 24
1
Generate random variate from a non-parametric hazard function
Hi
I have estimated a hazard function using a kernel based method. Now i have
to generate a random variate that follows this hazard function. Does any one
know method I should use to generate the variate.
Thanks
Samiul
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2002 Oct 08
2
sem (lisrel) - starting problems
Hi,
(1.)
How is it possible to get automatic a "lower triangle of correlation matrix" ?
h.cor <- cor(dat,use="pairwise.complete.obs")
zz <- lower.tri(h.cor,diag=T)
### that's not what i wish and "wrong" ?
results <- matrix(unlist(h.cor[upper.tri(h.cor,diag=T)]))
results <- matrix(unlist(h.cor[upper.tri(h.cor,diag=T)]),5)
Must i take the lowest
2005 Aug 17
1
GLM/GAM and unobserved heterogeneity
Hello,
I'm interested in correcting for and measuring unobserved
heterogeneity ("missing variables") using R. In particular, I'm
searching for a simple way to measure the amount of unobserved
heterogeneity remaining in a series of increasingly complex models
(adding additional variables to each new model) on the same data.
I have a static database of 400,000 or
2011 Nov 08
1
Help with SEM package: Error message
Hello.
I started using the sem package in R and after a lot of searching and trying
things I am still having difficulty. I get the following error message when
I use the sem() function:
Warning message:
In sem.default(ram = ram, S = S, N = N, param.names = pars, var.names =
vars, :
Could not compute QR decomposition of Hessian.
Optimization probably did not converge.
I started with a
2006 Jan 18
2
Migration?
I just installed ruby, lighttpd, and mysql from darwinports on me
laptop in lieu of the Apple version of ruby. Now when I fire up my
rails application, it''s not running lighttpd anymore -- it''s running
webrick. It also exits immediately. MySQL is running, the database
and tables are restored from the backup. What step am I missing?
Thanks for the help!
Cheers,
Hasan
2006 Jul 29
3
Engines question
I would like to get at all models in a rails application to be able to
add a field to every one of them as part of a migration. Something
like the following:
Appmodels.each { |x| add_column x.table_name.to_s, :foo, :text }
I understand I can get the table name using
ActiveRecord::Base#table_name, but how do I get all the models into an
array that I can use in the above manner?
--
Cheers,
Hasan
2006 Jan 10
1
Ferret -- Search Partial?
I''d like to implement the search capabilities of Ferret and am
looking for sample code to see how it''s done. I''m thinking my
controller creates the index when "Search" is clicked and a partial
is rendered. What is this partial supposed to look like? Is it built
in to rails/Ferret? Thanks for the help!
Cheers,
Hasan Diwan <hasan.diwan@gmail.com>
2010 May 26
2
Music on Hold
Hello
Yesterday, i brought linksys PAP2 and have success with that. The only thing that does not go well is the music on hold. When i press 'hold' button from the telephone set instead of playing the music on hold that i have setup in Asterisk, Telephone Set plays its own MOH. Is there any way to tackle this issue.
Regards
Taimur Hasan
-THQ- !!!ONE
2011 Sep 26
2
Randomly selecting rows with unique values in two columns
Hello,
I am trying to randomly select rows with unique values in columns 1 and 2. I
want to generate multiple subsets to estimate a statistic for each data set.
Below is a simplified example.
L1 L2 L3 L4 L5
1 a b 1 2 3
2 a c 4 5 6
3 a d 7 8 9
4 a e 10 11 12
5 a f 13 14 15
6 b c 16 17 18
7 b d 19 20 21
8 b e 22 23 24
9 b f 25 26 27
10 c d 28 29 30
11 c e
2010 Jul 08
2
Using nlm or optim
Hello,
I am trying to use nlm to estimate the parameters that minimize the
following function:
Predict<-function(M,c,z){
+ v = c*M^z
+ return(v)
+ }
M is a variable and c and z are parameters to be estimated.
I then write the negative loglikelihood function assuming normal errors:
nll<-function(M,V,c,z,s){
n<-length(Mean)
logl<- -.5*n*log(2*pi) -.5*n*log(s) -
2016 Aug 04
1
Fwd: RE: Query regarding LDAP
Hi All,
We currently have our AD on Windows Server 2008 setup to work with Samba
as a file share.
I noticed on our event logs in Windows that we are getting warnings
about a client performing LDAP binds without signing or using clear text
LDAP. After enabling the logging for LDAP i have found this to be our
Samba server performing these requests.
I know how to solve the issue so that our
2007 Jan 10
2
problems with optim, "for"-loops and machine precision
Dear R experts,
I have been encountering problems with the "optim" routine using "for"
loops. I am determining the optimal parameters of several nested models by
minimizing the negative Log-Likelihood (NLL) of a dataset.
The aim is to find the model which best describes the data. To this end, I
am simulating artificial data sets based on the model with the least number
2009 Apr 18
1
Modelling an "incomplete Poisson" distribution ?
Dear list,
I have the following problem : I want to model a series of observations
of a given hospital activity on various days under various conditions.
among my "outcomes" (dependent variables) is the number of patients for
which a certain procedure is done. The problem is that, when no relevant
patient is hospitalized on said day, there is no observation (for which
the "number
2006 Aug 26
1
problems with loop
Dear all,
I am trying to evaluate the optimisation behaviour of a function. Originally
I have optimised a model with real data and got a set of parameters. Now I
am creating simulated data sets based on these estimates. With these
simulations I am estimating the parameters again to see how variable the
estimation is. To this end I have written a loop which should generate a new
simulated data
2016 Jul 28
2
Re: Help
Thanks a lot. One more thing if I may... Will I just download and
install the packages from the http://packages.ubuntu.com ?
On 7/28/16, Pino Toscano <ptoscano@redhat.com> wrote:
> Hi,
>
> On Thursday, 28 July 2016 16:27:24 CEST M.H. Hasan Bhuiyan wrote:
>> I am a newbie in coding. I am using ubuntu 14.04 in my machine and
>> installed libguestfs by the following
2010 Jul 06
1
Error in affypdnn package
Dear all,
I am a PhD student working with Affymetrix HGU133atag array for analyzing the Latin square experiment.
I was trying to generate gene expression index for hgu133atag array for PDNN model. While extracting the chiptype specific data structure, I got the following error-
> library(affypdnn)
Loading required package: affy
Loading required package: Biobase
Welcome to Bioconductor
2011 Dec 23
2
Latent class multinomial (or conditional) logit using R?
Hi everyone?
Does anybody know how can I estimate a
Latent class multinomial (or conditional) logit using R?
I have tried flexmix, poLCA, and
they do not seem to support this model.
thanks in advance
adan
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2006 Feb 09
2
latent class modle for rater agreement
Hello there,
I would like to test the agreement amongst 6 raters for nominal data on
a scale from 1-4, and conduct a latent class analysis in R. How should
the data be formatted and what code should I use?
Thank you very much
Lisa Wang
Princess Margaret Hospital
Biostatistics
tel:416 946 4501
2006 Aug 09
1
scaling constant in optim("L-BFGS-B")
Hi all,
I am trying to find estimates for 7 parameters of a model which should fit
real data. I have a function for the negative log likelihood (NLL) of the
data. With optim(method="L-BFGS-B",lower=0) I am now minimizing the NLL to
find the best fitting parameters.
My problem is that the algorithm does not converge for certain data sets. I
have read that one should scale the fn
2007 Nov 08
1
finite mixture model (or latent class)
Dear Listers,
My post might be somewhat OT.
Currently, I am trying to use flexmix to build a finite mixture model.
For instance, I am getting the prior probability and coefficients for
each latent class from training data. Is there a way to get the
posterior probablity and prediction of a new dataset?
What I am thinking is to apply the prior prob and coefficient from
training set to testing data