Displaying 20 results from an estimated 400 matches similar to: "fit a nonlinear model using nlm()"
2012 Aug 31
2
Conditional merging in R & if then statement
1)I am wandering how the following SQL statement can be written in R language
w/o using sqldf:
create table detail2 as
select a.*
from detail a,
pdetail b
where a.TDATE=b.TDATE
and (a.STIM >= b.STIM and a.STIM <=b.MAXTIM)
2) when try if then in R it only applies to the 1st row & not to whole
dataset like in SAS. How do you get round that?
in SAS:
data summary;
set all1;
2012 Dec 02
1
Repeated-measures anova with a within-subject covariate (or varying slopes random-effects?)
Dear all,
I am having quite a hard time in trying to figure out how to correctly
spell out a model in R (a repeated-measures anova with a
within-subject covariate, I guess). Even though I have read in the
posting guide that statistical advice may or may not get an answer on
this list, I decided to try it anyway, hoping not to incur in
somebody's ire for misusing the tool.
For the sake of
2011 Feb 16
1
read.table - reading text variables as text
Hi
I'm reading a CSV file using read.table, and it keeps importing a text
variable as a factor. To overcome this, I've used the as.is command
referring to the variable in question (called "stim")
data<-read.table(file.choose(), header=T, sep=",", as.is = "stim")
However, "stim" is still imported as a factor. I notice there are other
read.table
2009 Dec 08
4
lower.tail option in pnorm
Hi,
I would have thought that these two constructions would
produce the same result but they do not.
Resp <- rbinom(10, 1, 0.5)
Stim <- rep(0:1, 5)
mm <- model.matrix(~ Stim)
Xb <- mm %*% c(0, 1)
ifelse(Resp, log(pnorm(Xb)), log(1 - pnorm(Xb)))
pnorm(as.vector(Xb), lower.tail = Resp, log.p = TRUE)
> ifelse(Resp, log(pnorm(Xb)), log(1 - pnorm(Xb)))
[1] -0.6931472 -1.8410216
2011 Feb 28
1
Creating new variables. How do you get them into a data frame?
Hi
I'm an R newbie. I can't seem to add new variables to data frames. Here are
the stages
(1) I import the data using read.csv.
(2) I fix it using fix(data)
(3) I create a new variable using
spos<-tagPOS(stim,language="en",model=NULL,tagdict=NULL).
(tagPOS is a function in the OpenNLP toolkit, which tags a string for part
of speech. "stim" is a variable in the
2013 Jun 07
1
Function nlme::lme in Ubuntu (but not Win or OS X): "Non-positive definite approximate variance-covariance"
Dear all,
I am estimating a mixed-model in Ubuntu Raring (13.04¸ amd64), with the
code:
fm0 <- lme(rt ~ run + group * stim * cond,
random=list(
subj=pdSymm(~ 1 + run),
subj=pdSymm(~ 0 + stim)),
data=mydat1)
When I check the approximate variance-covariance matrix, I get:
> fm0$apVar
[1] "Non-positive definite
2011 Mar 22
1
how to convert a data.frame to a list of dist objects for individual differences MDS?
I have a 45 x 16 data frame consisting of dissimilarities among 10
colors, giving in each
column the 45 = 10*9/2 pairwise judgments for one of 16 subjects. The
rownames
identify each pair of colors, e.g, "AC" = ("A","C"), and the pairs are
ordered by columns
in the lower triangle of each distance matrix.
> helm.raw <-
2013 Jul 20
1
how to calculate the average values of each row in a matrix
Hello,
I have a matrix (class matrix) composed of GridCell (row and column).
The matrix value is the beta diversity index value between two grids.
Now I would like to get the average value of each GridCell.
Please kindly advise how to make the calculation.
Thank you.
Elaine
The matrix looks like (cited from Michael Friendly)
I would like to get the average value of each color.
Obs
2007 Nov 06
1
Problem with a non-factor, non-numeric variable in a data.frame
Dear R list,
I would like to perform an ANOVA in a set of measurements, but I have
problems formatting the data.
The data is a two dimensional array containing two columns:
- "Stim" : the type of stimulation (string)
- "Ratio" : a ratio of two numeric values
Now, because some values are missing in the data (defaulting to zero),
part of this array will be populated with NA
2000 Oct 26
1
competing risks survival analysis
I will have data in the following form:
Time resp type stim type
300 a A
200 b A
155 a B
250 b B
80 c A
1000 d B
...
c is left censored observation; d is right censored
This sort of problem is discussed in Chap 9 of Cox & Oakes Analysis of
Survival Data under the name
2004 Aug 01
1
Preserving ACLs on files when copying from NT4 server to Samba 3.0.5 server
Hi guys.
I'm running:
Mandrake 9.2
Kernel 2.4.22-30mdk
XFS file system
Samba 3.0.5 plus patches for bugs 1315, 1319 and 1345 (self compiled)
OpenLDAP 2.1.22-5mdk
smbldap-tools 0.8.5
I was able to join the Samba to the NT PDC as a BDC and vampire without
issue. I have setup duplicate shares on Samba and am trying to copy
over the data from NT. I have tried scopy, xcopy and copying via
1998 Feb 27
1
R-beta: is there a way to get rid of loop?
Here is a programming question. The code I am using is quite slow and I
was wondering if there is a way to get rid of the for loop.
I am dealing with "interaction" in 2x2 table, and am using Edwards's G_I
(Likelihood, p. 194).
I label the cells in the table as follows
stim response
"y" "n" total
--------------------------------
y hit miss nsignal
2010 Feb 02
1
how to use optim() or nlm() to solve three nonlinear equations
Dear all,
I just know how to solve an eaquation by using optim() or nlm(). But, now, I have three nonlinear equations,
how could we use optim() or nlm() to solve a system of nonlinear equations in R? Thank you so much.
Sincerely,
Joe
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2012 Nov 15
6
Xen credit scheduler question
Hi all (and Mr. Dunlap in particular),
I have a question about the credit (and ultimately credit2) scheduler that I hope you can help me with.
I have read the white paper "Scheduler development update" and as much material on the credit scheduler as I can find, but I am still not completely clear on how I should think about the cap.
Example scenario:
Server hardware: 2
2008 Oct 26
20
Big test coming up: fallout 3
ok as everyone knows, (and to be frank i didnt think it would in my lifetime ;P) fallout 3 gets released in 3 days or 6 for those who live in europe.
now for those who where playing games since the 3rd grade the fallout universe has a special place in their hearts since literally i grew with it!
so in mho fallout 3 fells in the category of games that someone must simply have, and thats why im
2008 Mar 19
0
Error en nlm(logdgenexpn, p = c(vmomest[[1]], vmomest[[2]]), x = x.genexp, : valor no finito provisto por 'nlm'
Dear useRs,
I am analysing the behaviour of MLE for the two parameters of a kind
of exponential distribution, leaving as initial values the estimators
moments produced by the variation coefficient.
I do using simulations, giving them an accountant, r. But running my
codes remains a problem with the nlm function. To review details
wearing
On one of the lines put status
2010 Jun 15
1
Error in nlm : non-finite value supplied by 'nlm'
Hello,
I am trying to compute MLE for non-Gaussian AR(1). The error term follows a difference poisson distribution. This distribution has one parameter (vector[2]).
So in total I want to estimate two parameters: the AR(1) paramter (vector[1]) and the distribution parameter.
My function is the negative loglikelihood derived from a mixing operator.
f=function(vector)
2010 Aug 04
5
Question regarding significance of a covariate in a coxme survival model
Hi,
I am running a Cox Mixed Effects Hazard model using the library coxme. I
am trying to model time to onset (age_sym1) of thought problems (e.g.
hearing voices) (sym1). As I have siblings in my dataset, I have
decided to account for this by including a random effect for family
(famid). My covariate of interest is Mother's diagnosis where a 0 is
bipolar, 1 is control, and 2 is major
2003 Oct 24
1
first value from nlm (non-finite value supplied by nlm)
Dear expeRts,
first of all I'd like to thank you for the
quick help on my last which() problem.
Here is another one I could not tackle:
I have data on an absorption measurement which I want to fit
with an voigt profile:
fn.1 <- function(p){
for (i1 in ilong){
ff <- f[i1]
ex[i1] <- exp(S*n*L*voigt(u,v,ff,p[1],p[2],p[3])[[1]])
}
sum((t-ex)^2)
}
out <-
2002 Dec 11
0
nlm() vs. nls()
Dear R-experts!
I've been using nls() for a while for fitting my data, approx 10,000
points long. Now, I have to use low-level minimizing functions to get
more control on fitting process, so I tried nlm(). And, the fitting
process became *much* more slower!
The question is: why? why nls() works faster?
Thank you very much!
Timur.