Displaying 20 results from an estimated 2000 matches similar to: "VGAM and cnstraints"
2008 Apr 12
2
Predict Function
Hi all - my first time here and am having an issue with the Predict function.
I am using a tutorial as a guide, locate here:
http://www.ats.ucla.edu/STAT/R/dae/mlogit.htm
My code gives this error
> newdata1$predicted <- predict(mlogit,newdata=newdata1,type="response")
Error in `$<-.data.frame`(`*tmp*`, "predicted", value = c(0.332822934960197,
:
replacement has
2010 Mar 07
3
mlogit
I am trying to follow this example for multinomial logistic regression
http://www.ats.ucla.edu/stat/r/dae/mlogit.htm
However, I cannot get it to work properly.
This is the output I get, and I get an error when I try to use the mlogit
function. Any ideas as to why this happens?
> mydata <- read.csv(url("http://www.ats.ucla.edu/stat/r/dae/mlogit.csv"))
> attach(mydata)
>
2012 Dec 11
1
glm - predict logistic regression - entering the betas manually.
Dear All,
I know this may be a trivial question.
In the past I have used glm to make logistic regressions on data. The output creates an object with the results of the logistic regression. This object can then be used to make predictions.
Great.
I have a different problem. I need to make predictions from a logistic regression taken from a paper. Thus I need to (by hand) enter the reported odds
2010 Sep 10
1
lattice package - wireframe plot : adding more than one surface and addiding a curve overlaid on the plot
Dear R help,
Suppose I have a dataframe with three columns named p, v and C.
Here C is a function of both p and v. I can plot the surface C(p,v) using the package lattice using the function wireframe.
Now if I have another dataframe - with 2 columns named p_ind and v_ind and pind is a function of v_ind.
I would like to overlay the plot of the curve p_ind, v_ind and C(p_ind, v_ind) onto my
2010 Dec 15
0
Multinomial Analysis
I want to analyse data with an unordered, multi-level outcome variable, y. I am asking for the appropriate method (or R procedure) to use for this analysis.
> N <- 500
> set.seed(1234)
> data0 <- data.frame(y = as.factor(sample(LETTERS[1:3], N, repl = T,
+ prob = c(10, 12, 14))), x1 = sample(1:7, N, repl = T, prob = c(8,
+ 8, 9, 15, 9, 9, 8)), x2 = sample(1:7, N, repl =
2012 Nov 21
1
remote connection to an Oracle database - using RODBC - RMySQL..?
Dear users,
I can access an database oracle database using sql developer. This was done by importing an xml file that contains the login details - username, password and specifies that it uses the KERBEROS_AUTHENTICATION.
I'm trying to connect R - so that it can access this database - do sql queries and convert the resulting tables into dataframes.
I am a novice in SQL and database access
2012 Oct 23
1
Testing proportional odds assumption in R
I want to test whether the proportional odds assumption for an ordered
regression is met.
The UCLA website points out that there is no mathematical way to test the
proportional odds assumption (http://www.ats.ucla.edu/stat//R/dae/ologit.htm),
and use graphical inspection ("We were unable to locate a facility in R to
perform any of the tests commonly used to test the parallel slopes
2010 Jul 05
1
Memory problem in multinomial logistic regression
Dear All
I am trying to fit a multinomial logistic regression to a data set with a size of 94279 by 14 entries. The data frame has one "sample" column which is the categorical variable, and the number of different categories is 9. The size of the data set (as a csv file) is less than 10 MB.
I tried to fit a multinomial logistic regression, either using vglm() from the VGAM package or
2008 Oct 10
0
Problems and bugs in vgam()
Hello R-Users,
I have recently run into several problems using vgam() in the VGAM
package. I am hoping someone might have some solutions...
Briefly, I have been trying to fit GAM models for zero-altered negative
binomial models.
1. When fitting smoothed parameters (e.g. s(X, df=2)) changing the
degrees-of-freedom has no effect on the level of smoothing (e.g. number
of knots for the
2012 Jan 10
1
S4 summary method not being called (VGAM)
The symptom triggering this email is that an S4 summary method sometimes refuses to be invoked, even when a package is explicitly loaded, if the first load of the package is implicit. It may or may not be specific to 'summary' methods and/or the 'VGAM' package. I've sent to R-devel because (i) it looks like some kind of bug to me, but I'm not sure; (ii) it's not
2007 May 31
0
VGAM package
Hi, R-users
Could someone help me to understand this following error. I'm using vglm
function in VGAM package
Best regards and thank you for your ehlp
########
mydata <- read.table("Data2_overruns.csv", sep =";", header = T,
row.names=NULL)
> attach(mydata)
>
> y <- mydata$cat.event
> phase.vol <-mydata$phase.vol
> pilote <- mydata$pilote
2008 Nov 14
0
VGAM package released on CRAN
Dear Prof. Thomas Yee
I$B!G(Bm very interested in your R program VGAM.
I tried below your data:
# Nonparametric proportional odds model
data(pneumo)pneumo = transform(pneumo,
let=log(exposure.time))vgam(cbind(normal,mild,severe) ~ s(let),
cumulative(par=TRUE), pneumo)
However, the results by Version of VGAM are different;
----------The result by Version 0.7-7
2005 May 28
3
Incompatibility with VGAM
I just discovered that when the VGAM package (not on CRAN) is loaded,
glm() doesn't work. This is because VGAM defines a family function()
which gets found
by glm() in place of the family function from stats.
Then VGAM:::family returns an object which doesn't have a $family
component, (it has a component
$vfamily).
I thought namespaces should protect us from this happening?
Kjetil
--
2006 Oct 27
0
VGAM package released on CRAN
Dear useRs,
upon request, the VGAM package (currently version 0.7-1) has been
officially released on CRAN (the package has been at my website
http://www.stat.auckland.ac.nz/~yee/VGAM for a number of years now).
VGAM implements a general framework for several classes of
regression models using iteratively reweighted least squares
(IRLS). The key ideas are Fisher scoring, generalized linear
and
2005 Jun 06
0
VGAM weights
sorry...its the same post but this time with subject
dear all:
I want try the vgam function in VGAM library, but I'm stucked since I
can't define the weights. This is because I dont understand well the
concept of "matrix-band" (even after read the reference card).
I was wondering if someone have some tutorial examples of how to define
weights on a matrix form, in VGAM.
thank
2013 Apr 17
1
Bug in VGAM z value and coefficient ?
Dear,
When i multiply the y of a regression by 10, I would expect that the
coefficient would be multiply by 10 and the z value to stay constant. Here
some reproducible code to support the case.
*Ex 1*
library(mvtnorm)
library(VGAM)
set.seed(1)
x=rmvnorm(1000,sigma=matrix(c(1,0.75,0.75,1),2,2))
2011 Jun 22
2
VGAM constraints-related puzzle
Hello R users,
I have a puzzle with the VGAM package, on my first excursion into
generalized additive models, in that this very nice package seems to
want to do either more or less than what I want.
Precisely, I have a 4-component outcome, y, and am fitting multinomial
logistic regression with one predictor x. What I would like to find
out is, is there a single nonlinear function f(x) which acts
2011 Aug 23
1
P values for vglm(zibinomial) function in VGAM
Hi ,
I know this question has been asked twice in the past but to my knowldege,
it still hasn't been solved.
I am doing a zero inflated binomial model using the VGAM package, I need to
obtain p values for my Tvalues in the vglm output. code is as follows
> mod2=vglm(dmat~Season+Diel+Tidal.phase+Tidal.cycle,zibinomial, data=mp1)
> summary(mod2)
Call:
vglm(formula = dmat ~ Season +
2010 Jul 05
1
question concerning VGAM
Hello everyone,
using the VGAM package and the following code
library(VGAM)
bp1 <- vglm(cbind(daten$anzahl_b, daten$deckung_b) ~ ., binom2.rho,
data=daten1)
summary(bp1)
coef(bp1, matrix=TRUE)
produced this error message:
error in object$coefficients : $ operator not defined for this S4 class
I am bit confused because some day ago this error message did not show up
and
2008 Feb 08
0
Cumulative multinomial regression using VGAM
Hi,
I am trying to carry out a multinomial regression using the cumlogit link function. I have tried using the VGAM package, and have gotten some results...
fit1 <- vgam(Y ~ X1 + X2 + X3 + X4,
cumulative(link=logit,intercept.apply=FALSE,parallel=TRUE),
data = data1
)
The problem arrises when I try to get the information out of the fitted object. I can