Displaying 20 results from an estimated 1000 matches similar to: "what missed ----- CART"
2009 Mar 11
2
Couple of Questions about Classification trees
So I have 2 sets of data - a training data set and a test data set. I've been
doing the analysis on the training data set and then using predict and
feeding the test data through that. There are 114 rows in the training data
and 117 in the test data and 1024 columns in both. It's actually the same
set of data split into two. The rows are made of 5 different numbers. They
do represent
1998 Aug 18
1
Problem in "configure" for Solaris (cc) -- solved (partly) --
> From: Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk>
>
> Martin Maechler <maechler@stat.math.ethz.ch> writes:
>
> > Reading the long output of ``cc -flags'',
> > I see that more than average optimization is done using
> > cc -xO[1-4]
> > #
And -O is -xO2. If you do want higher speed, you need to use
other flags too, and -fast is a
2009 Apr 01
1
Request: Optimum value of cost complexity parameter "k" in "tree" package
Dear R community
I have a question regarding the value of cost complexity parameter "k" used in "tree" package for pruning purpose. Any help in finding the optimum value of "k" is requested. Please give some suggestion in this regard. In the example below i used k=0 but i don't know why? But if i use k=NULL, then it will not plot the resultant tree.
2008 Nov 17
1
An array of an array of boxplots in lattice
Using the data set fgl in MASS the following code
layout(matrix(1:9,3,3))
for(i in 1:9){
boxplot(fgl[,i] ~ type, data = fgl,main=dimnames(fgl)[[2]][i])}
produces a 3 by 3 array of plots, each one of which consists of six
boxplots.
Is it possible to do this in lattice?
Steve
"R version 2.7.2 (2008-08-25)" on Ubuntu 6.06
2007 Jun 16
0
Function for misclassification rate/type I,II error??
HI
Is there any function in R that tells us error rate(misclassification rate)
for logistic regression type classification?
i also want to know the function to determine type I and type II error.
I have found a link where "misclass" and "confusion" are used. But I dont
know the package name.
http://alumni.media.mit.edu/~tpminka/courses/36-350.2001/lectures/day32/
2017 Jun 18
0
R_using non linear regression with constraints
> On Jun 18, 2017, at 6:24 AM, Manoranjan Muthusamy <ranjanmano167 at gmail.com> wrote:
>
> I am using nlsLM {minpack.lm} to find the values of parameters a and b of
> function myfun which give the best fit for the data set, mydata.
>
> mydata=data.frame(x=c(0,5,9,13,17,20),y = c(0,11,20,29,38,45))
>
> myfun=function(a,b,r,t){
> prd=a*b*(1-exp(-b*r*t))
>
2005 Nov 10
1
question about the dataset fgl
Dear sir or ma'am,
I have a question about the dataset "fgl." The dataset seems to be in
the "VR" package, so I tried to download it from CRAN. However, after
downloading, when I tried to load the package, it was not in my package
list. I am wondering what is wrong.
Any advice on how to access the fgl dataset would be appreciated.
Thanks.
Seungho Huh
2017 Jun 18
0
R_using non linear regression with constraints
I ran the following script. I satisfied the constraint by
making a*b a single parameter, which isn't always possible.
I also ran nlxb() from nlsr package, and this gives singular
values of the Jacobian. In the unconstrained case, the svs are
pretty awful, and I wouldn't trust the results as a model, though
the minimum is probably OK. The constrained result has a much
larger sum of squares.
2017 Jun 18
3
R_using non linear regression with constraints
https://cran.r-project.org/web/views/Optimization.html
(Cran's optimization task view -- as always, you should search before posting)
In general, nonlinear optimization with nonlinear constraints is hard,
and the strategy used here (multiplying by a*b < 1000) may not work --
it introduces a discontinuity into the objective function, so
gradient based methods may in particular be
2020 Oct 17
2
??? is to nls() as abline() is to lm() ?
I'm drawing a fitted normal distribution over a histogram. The use case is trivial (fitting normal distributions on densities) but I want to extend it to other fitting scenarios. What has stumped me so far is how to take the list that is returned by nls() and use it for curve(). I realize that I can easily do all of this with a few intermediate steps for any specific case. But I had expected
2017 Jun 18
0
R_using non linear regression with constraints
I've seen a number of problems like this over the years. The fact that the singular values of the Jacobian have
a ration larger than the usual convergence tolerances can mean the codes stop well before the best fit. That is
the "numerical analyst" view. David and Jeff have given geometric and statistical arguments. All views are useful,
but it takes some time to sort them all out and
2020 Oct 17
0
??? is to nls() as abline() is to lm() ?
I haven't followed your example closely, but can't you use the predict()
method for this? To draw a curve, the function that will be used in
curve() sets up a newdata dataframe and passes it to predict(fit,
newdata= ...) to get predictions at those locations.
Duncan Murdoch
On 17/10/2020 5:27 a.m., Boris Steipe wrote:
> I'm drawing a fitted normal distribution over a
2017 Jun 18
3
R_using non linear regression with constraints
I am not as expert as John, but I thought it worth pointing out that the
variable substitution technique gives up one set of constraints for
another (b=0 in this case). I also find that plots help me see what is
going on, so here is my reproducible example (note inclusion of library
calls for completeness). Note that NONE of the optimizers mentioned so far
appear to be finding the true best
2012 Aug 25
2
Standard deviation from MANOVA??
Hi,
I have problem getting the standard deviation from the manova output.
I have used the manova function: myfit <- manova(cbind(y1, y2) ~ x1
+ x2 + x3, data=mydata) .
I tried to get the predicted values and their standard deviation by using:
predict(myfit, type="response", se.fit=TRUE)
But the problem is that I don't get the standard deviation values, I only
2011 Jan 25
1
Predictions with 'missing' variables
Dear List,
I think I'm going crazy here...can anyone explain why do I get the same
predictions in train and test data sets below when the second has a missing
input?
y <- rnorm(1000)
x1 <- rnorm(1000)
x2 <- rnorm(1000)
train <- data.frame(y,x1,x2)
test <- data.frame(x1)
myfit <- glm(y ~ x1 + x2, data=train)
summary(myfit)
all(predict(myfit, test) == predict(myfit, train))
2007 Mar 12
1
knncat question
I use knncat to make a predictive model
and get misclass rate
> knncat.m<-knncat(training.new,k=c(10,20),classcol=5)
> knncat.m
Training set misclass rate: 36.88%
then I try to calculate prediction accuracy by the following:
> pr.knncat.train <- predict
(knncat.m,training.new,training.new,train.classcol=5,newdata.classcol=5)
> tb.knncat.train <-table (pr.knncat.train,
2003 Oct 23
3
List of lm objects
Hi R-Helpers:
I?m trying to fit the same linear model to a bunch of variables in a data
frame, so I was trying to adapt the codes John Fox, Spencer Graves and Peter
Dalgaard proposed and discused yesterday on this e-mail list:
for (y in df[, 3:5]) {
mod = lm(y ~ Trt*Dose, data = x, contrasts = list(Trt =
contr.sum, Dose = contr.sum))
Anova(mod, type = "III")
} ## by John Fox
or
for
2006 Mar 05
1
duration analysis
Hi,
I am trying to estimate the effects of covariates on the hazard function, rather
than on the survival. I know this is actually the same thing. For example, using
the survival package, and doing:
> myfit <- survreg( Surv(time, event) ~ mymodel )
all I have to do to get the quantities of my interest is
> -myfit$coefficients/myfit$scale
The standard erros are easily worked out, as
2007 Jan 21
1
for loop problem
Hello R users,
A beginners question which I could not find the answer to in earler posts.
My thought process:
Here "z" is a 119 x 15 data matrix
Step 1: start at column one, bind every column with column 1
Step2: use the new matrix, "test", in the fitCopula package
Step3: store each result in myfit, bind each result to "answer"
Step4: return "answer"
2010 Sep 19
2
working with eval and environments
I'm trying to get the following section of code to work, I think the problem
is being caused by the assignment of data to the lm function not evaluating
to "train" in the parent environment but I can't seem to figure out how to
do this.
fitmodel <- function(trial,data)
{
wrap.lm <- function(formula,data,...) { cat("in wrap lm",NROW(data),"\n");