Displaying 20 results from an estimated 11000 matches similar to: "SSlogis problem with min(y)==0"
2008 Jan 04
3
nls (with SSlogis model and upper limit) never returns (PR#10544)
Full_Name: Hendrik Weisser
Version: 2.6.1
OS: Linux
Submission from: (NULL) (139.19.102.218)
The following computation never finishes and locks R up:
> values <- list(x=10:30, y=c(23.85, 28.805, 28.195, 26.23, 25.005, 20.475,
17.33, 14.97, 11.765, 8.857, 5.3725, 5.16, 4.2105, 2.929, 2.174, 1.25, 1.0255,
0.612, 0.556, 0.4025, 0.173))
> y.max <- max(values$y)
> model <- nls(y ~
2008 Apr 14
3
Logistic regression
Dear all,
I am trying to fit a non linear regression model to time series data.
If I do this:
reg.logis = nls(myVar~SSlogis(myTime,Asym,xmid,scal))
I get this error message (translated to English from French):
Erreur in nls(y ~ 1/(1 + exp((xmid - x)/scal)), data = xy, start =
list(xmid = aux[1], :
le pas 0.000488281 became inferior to 'minFactor' of 0.000976562
I then tried to set
2011 Nov 17
3
Obtaining a derivative of nls() SSlogis function
Hello, I am wondering if someone can help me. I have the following function
that I derived using nls() SSlogis. I would like to find its derivative. I
thought I had done this using deriv(), but for some reason this isn't
working out for me.
Here is the function:
asym <- 84.951
xmid <- 66.90742
scal <- -6.3
x.seq <- seq(1, 153,, 153)
nls.fn <- asym/((1+exp((xmid-x.seq)/scal)))
2011 Aug 09
1
nls, how to determine function?
Hi R help,
I am trying to determine how nls() generates a function based on the
self-starting SSlogis and what the formula for the function would be.
I've scoured the help site, and other literature to try and figure
this out but I still am unsure if I am correct in what I am coming up
with.
**************************************************************************
dat <-
2009 Oct 02
1
nls not accepting control parameter?
Hi
I want to change a control parameter for an nls () as I am getting an error
message "step factor 0.000488281 reduced below 'minFactor' of 0.000976562".
Despite all tries, it seems that the control parameter of the nls, does not
seem to get handed down to the function itself, or the error message is
using a different one.
Below system info and an example highlighting the
2001 Jun 01
1
nls works but not gnls
This works fine:
fit42<-nls(Vfs~SSlogis(Months,Asym.Int+Asym.Group*Groupdum,xmid,scal),
data=df,
start=c(Asym.Int=22,Asym.Group=5,xmid=2,scal=6),
na.action=na.omit)
But this, identical except using gnls, doesn't converge:
fit43<-gnls(Vfs~SSlogis(Months,Asym.Int+Asym.Group*Groupdum,xmid,scal),
data=df,
start=c(Asym.Int=22,Asym.Group=5,xmid=2,scal=6),
na.action=na.omit)
Error in gnls(Vfs
2010 Mar 29
1
getting CI's for certain y of nls fitted curve
hello,
i managed to get CI's for my curve - but now I need the intervall for a
certain y point (y_tenth) of the curve..
can anyone help me with this?
#####data:
por<-data.frame(list(structure(list(run = structure(c(1L, 1L, 1L, 1L, 2L,
2L,
2L, 2L, 3L, 3L, 3L, 3L), .Label = c("1", "3", "4"), class = "factor"),
press = c(15, 21, 24, 29.5, 15, 21,
2004 May 18
0
nlme: Initial parameter estimates
Hello,
I am trying to fit a nlme (non linear mixed effect). I am using the SelfStart function SSlogis. However the data in my hand contains few observations per subject (4 or less), so the nlsList doesn't work... In this case I should fixe initial parameter estimates. I remark that values of initial estimates have a greater effect on the model fit (i.e. loglikelihood, AIC and also on
2009 Nov 09
1
Parameter info from nls object
Hi!
When checking validity of a model for a large number
of experimental data I thought it to be interesting
to check the information provided by
the summary method programmatically.
Still I could not find out which method to
use to get to those data.
Example (not my real world data, but to show the point):
[BEGIN]
> DNase1 <- subset(DNase, Run == 1)
> fm1DNase1 <- nls(density ~
2017 Oct 20
1
Error messages using nonlinear regression function (nls)
Thank you Martin.
If I understand correctly, OP could do
wheat.list <- nlsList(Prop ~ SSfpl(end, A, B, xmid, scal), data=wlg)
or add some small value to all zeroes
wlg$prop < -wlg$Prop+1e-7
wheat.list <- nlsList(prop ~ SSlogis(end,Asym, xmid, scal), data=wlg)
which gives fairly reasonable results.
plot(augPred(wheat.list))
Am I correct?
Cheers
Petr
> -----Original Message-----
2001 May 01
0
SSfpl self-start sometimes fails... workaround proposed
Hello,
nls library provides 6 self-starting models, among them: SSfp, a four
parameters logistic function. Its self-starting procedure involves several
steps. One of these steps is:
pars <- as.vector(coef(nls(y ~ cbind(1, 1/(1 + exp((xmid - x)/exp(lscal)))),
data = xydata, start = list(lscal = 0), algorithm = "plinear")))
which assumes an initial value of lscal equal to 0. If lscal
2004 Aug 10
0
Check failed after compilation (PR#7159)
Full_Name: Madeleine Yeh
Version: 1.9.1
OS: AIX 5.2
Submission from: (NULL) (151.121.225.1)
After compiling R-1.9.1 on AIX 5.2 using the IBM cc compiler, I ran the
checks. One of them failed. Here is the output from running the check solo.
root@svweb:/fsapps/test/build/R/1.9.1/R-1.9.1/tests/Examples:
># ../../bin/R --vanilla < stats-Ex.R
R : Copyright 2004, The R
2000 Feb 11
1
R CMD check [nlme|MASS] fails (PR#431)
Mmmh, seems as if I really should change my options as I seem to keep
sending off empty bug-reports ;-/ Sorry guys. Here is the content
that should have been in the last e-mail:
`R CMD check nlme' fails on my machine. The final output in
nlme-Ex.Rout is:
> library(nlme)
> data(Soybean)
> fm1 <- nlme(weight ~ SSlogis(Time, Asym, xmid, scal), data = Soybean,
+ fixed =
2009 May 04
1
how to change nlme() contrast parametrization?
How to set the nlme() function to return the answer without the intercept parametrization?
#=========================================================================================
library(nlme)
Soybean[1:3, ]
(fm1Soy.lis <- nlsList(weight ~ SSlogis(Time, Asym, xmid, scal),
data = Soybean))
(fm1Soy.nlme <- nlme(fm1Soy.lis))
fm2Soy.nlme <- update(fm1Soy.nlme,
2017 Feb 22
0
Crash in the latest release
I found this by accident yesterday. The program that crashes is the first two lines of
the example from the help page for nlmer. That example hasn't changed in a long time, so I
assumed that it is an R-devel issue. It could also be a long latent nlmer bug. The second
run with valgrind is puzzling.
Terry T.
> library(lmer)
> sessionInfo()
R Under development (unstable)
2017 Oct 20
0
Error messages using nonlinear regression function (nls)
>>>>> PIKAL Petr <petr.pikal at precheza.cz>
>>>>> on Fri, 20 Oct 2017 06:33:36 +0000 writes:
> Hi
> Keep your messages in the list, you increase your chance to get some answer.
> I changed your data to groupedData object (see below), but I did not find any problem in it.
> plot(wlg)
> gives reasonable picture and I am
2009 Jul 30
1
Continue to finish for loop even there is an error in one of rounds.
I am trying to fit a logistic model to my 10 year data (1999-2008) by year. Codes like below:
Year <- c(1999: 2008)
for(y in 1:length(year)) {
file.input <- paste("C:\\", year[y], "\\data.csv", sep="")
table <- read.csv(file=fileinput, header=TRUE, as.is=TRUE, na.strings=c(""))
initial <- getInitial(percent ~ SSlogis(age, Asym,
2004 Aug 19
0
NLME: Holding constant the across group correlational structure of the fixed effects in nlme
Hello all.
I was wondering if there is a way to hold constant the fixed effects correlation structure across multiple groups?
For example, I have two groups and I fit a three parameter logistic growth curve where the fixed effects are free to vary across the groups. I'll paste in the code as a concrete example:
> Result.NLME <- nlme(Score ~ SSlogis(Time, Asym, xmid, scal),
+
2017 Feb 22
0
[Lme4-authors] Crash in the latest release
Thanks, posted to https://github.com/lme4/lme4/issues/412 for further
discussion ...
On Wed, Feb 22, 2017 at 10:03 AM, Therneau, Terry M., Ph.D.
<therneau at mayo.edu> wrote:
> I found this by accident yesterday. The program that crashes is the first
> two lines of the example from the help page for nlmer. That example hasn't
> changed in a long time, so I assumed that it is
2001 Aug 08
1
NLME augPred error
Could someone explain the meaming of this error message from augPred:
> augPred(area3.pen.nlme, primary=~day)
Error in predict.nlme(object, value[1:(nrow(value)/nL), , drop =
FALSE], :
Levels 1,2,3 not allowed for block
>
predict.nlme(area3.pen.nlme) does not produce an error.
area3.pen.nlme was created with:
> area3.pen.nlme <- nlme(area ~ SSlogis(day, Asym, xmid, scal),