Displaying 20 results from an estimated 10000 matches similar to: "Logistic regression with constrained parameter ??"
2005 Dec 08
1
logistic regression with constrained coefficients?
I am trying to automatically construct a distance function from
a training set in order to use it to cluster another data set.
The variables are nominal. One variable is a "class" variable
having two values; it is kept separate from the others.
I have a method which constructs a distance matrix for the levels
of a nominal variable in the context of the other variables.
I want to
2008 Sep 28
0
constrained logistic regression: Error in optim() with method = "L-BFGS-B"
Dear R Users/Experts,
I am using a function called logitreg() originally described in MASS (the
book 4th Ed.) by Venebles & Ripley, p445. I used the code as provided but
made couple of changes to run a 'constrained' logistic regression, I set the
method = "L-BFGS-B", set lower/upper values for the variables.
Here is the function,
logitregVR <- function(x, y, wt =
2005 Mar 28
1
mixed model question
I am trying to fit a linear mixed model of the form
y_ij = X_ij \beta + delta_i + e_ij
where e_ij ~N(0,s^2_ij) with s_ij known
and delta_i~N(0,tau^2)
I looked at the ecme routine in package:pan, but this routine
does not allow for different Vi (variance covariance matrix of
the e_i vector) matrices for each cluster.
Is there an easy way to fit this model in R or should I bite the
bullet and
2008 Dec 28
1
Logistic regression with rcs() and inequality constraints?
Dear guRus,
I am doing a logistic regression using restricted cubic splines via
rcs(). However, the fitted probabilities should be nondecreasing with
increasing predictor. Example:
predictor <- seq(1,20)
y <- c(rep(0,9),rep(1,10),0)
model <- glm(y~rcs(predictor,n.knots=3),family="binomial")
print(1/(1+exp(-predict(model))))
The last expression should be a nondecreasing
2006 Sep 27
2
Constrained OLS regression
Hello R helpers,
I am trying to do a linear OLS regression of y on two variables x1 and
x2. I want to constrain the coefficients of x1 and x2 to sum up to 1.
and therefore run a constrained OLS. Can anybody help with this? (I have
seen some answers to similar questions but it was not clear to me what I
need to do) - I have tried the lm function with offset but I must not
have used it properly.
2011 Jun 30
1
Error "singular gradient matrix at initial parameter estimates" in nls
Greetings,
I am struggling a bit with a non-linear regression. The problem is
described below with the known values r and D inidcated.
I tried to alter the start values but get always following error
message:
Error in nlsModel(formula, mf, start, wts):
singular gradient matrix at initial parameter estimates
Calls: nls -> switch -> nlsModel
I might be missing something with regard to the
2007 Nov 28
2
fit linear regression with multiple predictor and constrained intercept
Hi group,
I have this type of data
x(predictor), y(response), factor (grouping x into many groups, with 6-20
obs/group)
I want to fit a linear regression with one common intercept. 'factor'
should only modify the slopes, not the intercept. The intercept is expected
to be >0.
If I use
y~ x + factor, I get a different intercept for each factor level, but one
slope only
if I use
y~ x *
2005 Jun 08
1
Bounding or constraining parameters in non-linear regressions
Dear R-Users,
Being an engineer and not a statistician, my desired course of action may
either be impossible or very simple.
I am attempting to fit a non-linear model to some measured data. One term in
the model contains a square-root, but in the course of regression, this term
turns negative and an error occurs. I started using Micrsoft's Excel Solver,
and then I turned to NIST's
2011 Sep 19
1
Constrained regressions (suggestions welcome)
All,
Could anyone recommend a package that allows the user to constrain the
coefficients from a multiple regression equation?
I tried using the gl1ce function in lasso2, but couldn't get it to
work. I created a contrived example to illustrate my starting point.
data(cars)
fmla <- formula(dist ~ speed)
gl1c.E <- gl1ce(fmla, data = cars)
gl1c.E
gl1c.E <- gl1ce(fmla, data =
2006 Aug 09
1
minimization a quadratic form with some coef fixed and some constrained
Hello, all,
I had problems with an extension to a classic optimization problem.
The target is to minimize a quadratic form a'Ma with respect to vector
b, where vector a=(b',-1)', i.e., a is the expand of b, and M is a
symmetric matrix (positive definite if needed). One more constrain on b
is b'b=1. I want to solve b given M.
I tried but it seems impossible to find an analytic
2010 Aug 24
1
Constrained non-linear optimisation
I'm relatively new to R, but I'm attempting to do a non-linear maximum
likelihood estimation (mle) in R, with the added problem that I have a
non-linear constraint.
The basic problem is linear in the parameters (a_i) and has only one
non-linear component, b, with the problem being linear when b = 0 and
non-linear otherwise. Furthermore, f(a_i) <= b <= g(a_i) for some
(simple) f
2010 Jan 26
1
Hypothsis simulation
I wish to simulate:
Ho: Odds Ratio =1
H1 Odds Ratio <> 1
Can any of the R users show me how to generate this data for say 20% from Ho
and 80% from H1?
Thanks,
Jim
[[alternative HTML version deleted]]
2005 Feb 28
2
A problem about outer()
Dear all,
I have something about function outer() that I can't understand. Just see the following example. The two NaNs are due to 0/0, but I can't figure out the cause of the last two errors. I wonder if some one can explain this for me.
___________________________________________________________________
> sx=rbinom(10,1,0.5);ot=rbinom(10,1,0.5);ag <- rbinom(10,100,0.3);ho <-
2005 Jun 07
1
Help with possible bug (assigning NA value to data.frame) ?
There's something peculiar that I do not understand here. However, did you
realize that the thing you are assigning into parts of `a' is NULL? Check
you're my.test.boot.ci.1: It's NULL.
Be that as it may, I get:
> a <- data.frame(matrix(1:4, nrow=2), X3=NA, X4=NA)
> a
X1 X2 X3 X4
1 1 3 NA NA
2 2 4 NA NA
> a[a$X1 == 1,]$X3 <- NULL
> a
X1 X2 X3 X4
1 1
2019 Apr 10
1
chown: changing ownership of 'test': Invalid argument
Ok i've comment in between de debug logs.
Check my comments and add the needed info.
Van: Ian Coetzee [mailto:samba at iancoetzee.za.net]
Verzonden: woensdag 10 april 2019 10:17
Aan: L.P.H. van Belle
CC: samba at lists.samba.org
Onderwerp: Re: [Samba] chown: changing ownership of 'test': Invalid argument
Hi Louis,
Thank you. I will add those line and test. Will revert
2015 Jan 09
4
help, please, troubleshooting winbind testing during setup of Samba 4 AD member server
Hello, all!
Well, third time is *not* the charm for me. (I've been through the
process 3 times with 3 different DCs).
I am trying to set up a member server, using Samba 4.1.14, and washing
out when getting to the winbind testing. I've tried ignoring the failure
and pressing on, but that didn't get anywhere.
In this instance, I have a freshly-installed, configured and functioning
2008 Mar 03
1
Tapply for Group Specific Means and Proportions
UseRs,
I am working on a dataset (see small example below) where individuals
were followed on a specific date-time combo and multiple repeated
measurements were taken (e.g., height in meters, behavior class in 2
letter code). Observation numbers varied between individual (ranging
from 1 observation for each date-time combo to >50)
I am trying to summarize the data into 1 row per
2008 Jul 19
2
Non-linearly constrained optimisation
Dear R Users,
I am looking for some guidance on setting up an optimisation in R with
non-linear constraints.
Here is my simple problem:
- I have a function h(inputs) whose value I would like to maximise
- the 'inputs' are subject to lower and upper bounds
- however, I have some further constraints: I would like to constrain the
values for two other separate function f(inputs) and
2007 Oct 11
1
constraining correlations
Hello,
I've searched for an answer to no avail. I am wondering if anyone
knows how to constrain certain correlations to be equal. I have family
data with 2 twins per family plus up to 2 siblings. I would like to
somehow constrain all the sibling correlations (twin-sib and sib-sib)
to be the same while allowing the twin-twin correlation to be
different. Here is some simulated code:
2008 Dec 03
1
GLMM using lme4
Dear R-experts,
I am running R version 2.7.1 on Windows Vista. I have a small dataset which consists of ?chick ID?, ?year (0, 1)?, ?hatching order [HO, defined as first, second and third-hatched chick]?, and the binary outcome of interest ?death (0, 1)?. So a subset of my dataset looks like this on a txt file:
y ID Yr HO
1 1 1 First
0 2 1 First
0 3 1 Second
0 4 1 First
1 5 1 First
0 6 1 Third