Displaying 20 results from an estimated 4000 matches similar to: "Step and AIC"
2010 Jan 18
2
Rotating pca scores
Dear Folks
I need to rotate PCA loadings and scores using R.
I have run a pca using princomp and I have rotated PCA results with
varimax. Using varimax R gives me back just rotated PC loadings without
rotated PC scores.
Does anybody know how I can obtain/calculate rotated PC scores with R?
Your kindly help is appreciated in advance
Francesca
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2011 Feb 03
1
glmnet with binary predictors
Hi Everybody!
I must start with a declaration that I am a sparse user of R. I am
creating a credit scorecard using a dataset which has a variable
depicting actual credit history (good/bad) and 41 other variables of
yes/no type. The procedure I am asked to follow is to use a penalized
logistic procedure for variable selection. I have located the package
"glmnet" which gives the complete
2011 Jan 24
2
Implementing step-wise linear regression
Dear R fans,
I am trying to do step-wise linear regression using the F-test to decide
which variables to admit. Ewout Steyerberg suggests using the F-test for
this purpose.
I first build a model using no variables using lm(y ~ 1) and then using one
variable that is a strong predictor using lm(y ~ x). When I call var.test
on these two models, I do not get a significant p-value—0.07. But a
2012 Apr 14
2
master thesis
Hi,
For my master thesis I have 24 micro-plots on which I did measurements during 3 months.
The measurements were:
- Rainfall and runoff events throughout 3monts (runoff being dependant on the rainfall, a coefficient (%) has been made per rainfall event and per 3 months)
- Soil texture (3 different textures were differentiated)
- Slope (3 classes of slopes)
- Stoniness (one time measurement)
2013 Mar 14
1
Elasticnet - Cross validation problem
Hello,
I am attempting to use elasticnet to classify a number of documents.
The features are words. The data is coded into a matrix with each document as a row and each word as a column. The data is binary, with {0,1} indicating the presence of a word.
I want to use the cross validation function of elasticnet (cv.enet). However, when the code selects a random subset of the data for a given
2009 Mar 17
1
Double Cross validation for LASSO
Dear R user,
I am looking for a code on double cross validation in
LASSO , one for optimizing the parameter and other one is for MSEP. If any
one have it, please foroward to me. I am using different package like LARS,
chemometric etc.
Thanks in advance
Alex
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2011 Jun 06
1
Lasso for k-subset regression
Dear R-users
I'm trying to use lasso in lars package for subset regression, I have a
large matrix of size 1000x100 and my aim is to select a subset k of the 100
variables.
Is there any way in lars to fix the number k (i.e. to select the best 10
variables)
library(lars)
aa=lars(X,Y,type="lasso",max.steps=200)
plot(aa,plottype="Cp")
aa$RSS
which.min(aa$RSS)
2012 May 25
2
Collecting results of a test with array
Dear contributors
I have tried this experiment:
x<-c()
for (i in 1:12){
x[i]<-list(cbind(x1[i],x2[i])) #this is a list of 12 couples of time
series I am using to perform a test
} # that compares them 2 by 2
#
#################
#trace statistic
test<-data.frame()
cval<-array( , dim=c(2,3,12))
for (i in 2:12){
for (k in 1:2){
for (j in 1:3){
result[k,j,i]<-
2012 Mar 01
1
GLM with regularization
Hello,
Thank you for probably not so new question, but i am new to R.
Does any of packages have something like glm+regularization? So far i
see probably something close to that as a ridge regression in MASS but
I think i need something like GLM, in particular binomial regularized
versions of polynomial regression.
Also I am not sure how some of the K-fold crossvalidation helpers out
there
2011 Oct 03
2
Merge two data frames and find common values and non-matching values
Hi,
I am trying to find a function to match two data frames of different lengths
for one field only.
So, for example,
df1 is:
Name Position location
francesca A 75
cristina B 36
And df2 is:
location Country
75 UK
56 Austria
And I would like to match on "Location" and the output to be something like:
Name Position Location Match
francesca A 75 1
cristina B 36 0
I have tried with
2011 Jul 27
3
Reorganize(stack data) a dataframe inducing names
Dear Contributors,
thanks for collaboration.
I am trying to reorganize data frame, that looks like this:
n1.Index Date PX_LAST n2.Index Date.1 PX_LAST.1
n3.Index Date.2 PX_LAST.2
1 NA 04/02/07 1.34 NA 04/02/07 1.36
NA 04/02/07 1.33
2 NA 04/09/07 1.34 NA 04/09/07
2012 Jan 20
3
Istalling Ruby 1.9.2
I just installed 1.9.2 on my 2nd machine, but after I installed I checked
the version with ruby -v and it sent me 1.8.7
Here''s the terminal output...anyone know what''s wrong (I have RVM
installed):
Francescas-MacBook-Air:~ fkrihely$ rvm install 1.9.2
Fetching yaml-0.1.4.tar.gz to /Users/fkrihely/.rvm/archives
Extracting yaml-0.1.4.tar.gz to /Users/fkrihely/.rvm/src
Configuring
2017 Oct 19
0
Select part of character row name in a data frame
(Re-)read the discussion of indexing (both `[` and `[[`) and be sure to get clear on the difference between matrices and data frames in the Introduction to R document that comes with R. There are many ways to create numeric vectors, character vectors, and logical vectors that can then be used as indexes, including the straightforward way:
df[ c(
"Unique to strat ",
"Unique
2012 May 18
3
How to fix indeces in a loop
Dear Contributors,
I have an easy question for you which is puzzling me instead.
I am running loops similar to the following:
for (i in c(100,1000,10000)){
print((mean(i)))
#var<-var(rnorm(i,0,1))
}
This is what I obtain:
[1] 100
[1] 1000
[1] 10000
In this case I ask the software to print out the result, but I would
like to store it in an object.
I have tried a second loop, because if I
2013 Jan 27
2
Loops
Dear Contributors,
I am asking help on the way how to solve a problem related to loops for
that I always get confused with.
I would like to perform the following procedure in a compact way.
Consider that p is a matrix composed of 100 rows and three columns. I need
to calculate the sum over some rows of each
column separately, as follows:
fa1<-(colSums(p[1:25,]))
fa2<-(colSums(p[26:50,]))
2017 Oct 19
2
Select part of character row name in a data frame
Thanks a lot, so simple so efficient!
I will study more the grep command I did not know.
Thanks!
Francesca Pancotto
> Il giorno 19 ott 2017, alle ore 12:12, Enrico Schumann <es at enricoschumann.net> ha scritto:
>
> df[grep("strat", row.names(df)), ]
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2013 Jul 06
1
problem with BootCV for coxph in pec after feature selection with glmnet (lasso)
Hi,
I am attempting to evaluate the prediction error of a coxph model that was
built after feature selection with glmnet.
In the preprocessing stage I used na.omit (dataset) to remove NAs.
I reconstructed all my factor variables into binary variables with dummies
(using model.matrix)
I then used glmnet lasso to fit a cox model and select the best performing
features.
Then I fit a coxph model
2010 Jul 08
1
glmnet - choosing the number of features
Hi,
I am trying to use the glmnet package to do some simple feature selection.
However, I would ideally like to be able to specify the number of features
to return (the glmnet package, as far as I can tell, only allows
specification of a regularization parameter, lambda, that in turn returns a
model with a specific number of non-zero features).
Is there a straightforward way of calculating the
2004 Sep 20
3
montecarlo simulation
Hy!
I would like to know how run a montecarlo simulation with R.
Thank you!!!!
Francesca Matalucci
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2004 Mar 23
1
help on data.frames/data.entry
Dear R-help,
I have a matrix D of dimensions 200 x 26; rows are my cases and columns are
my variables. I would like to create a data.frame "DF" with row.names=
myrownames (this is a vector of characters of length 200) and column names
"mycolnames" (a vector of characters of length 26). I could find the option
in data.frame for naming rows, but not for naming columns. So I