similar to: Letter for request

Displaying 20 results from an estimated 20000 matches similar to: "Letter for request"

2006 Mar 06
0
Problems with R CMD Rdconv and R CMD Sd2Rd (PR#8661)
I'm using R 2.2.0 on Windows. Doing some conversions of help files. Internal comments indicate that the Sd2Rd conversion is "Converted by Sd2Rd version 1.21." I'm converting .d -> .Rd .sgml -> .Rd using Sd2Rd, then checking by using Rdconv to convert .Rd back to .d or .sgml. Here are errors in some of the conversions. The most significant errors are in .Rd to .sgml.
2006 Sep 15
2
LARS for generalized linear models
Hi, Is there an R implementation of least angle regression for binary response modeling? I know that this question has been asked before, and I am also aware of the "lasso2" package, but that only implements an L1 penalty, i.e. the Lasso approach. Madigan and Ridgeway in their discussion of Efron et al (2004) describe a LARS-type algorithm for generalized linear models. Has
2003 Apr 30
0
Least Angle Regression packages for R
Least Angle Regression software: LARS "Least Angle Regression" ("LAR") is a new model selection algorithm; a useful and less greedy version of traditional forward selection methods. LAR is described in detail in a paper by Brad Efron, Trevor Hastie, Iain Johnstone and Rob Tibshirani, soon to appear in the Annals of Statistics. The paper, as well as R and Splus packages, are
2003 Apr 30
0
Least Angle Regression packages for R
Least Angle Regression software: LARS "Least Angle Regression" ("LAR") is a new model selection algorithm; a useful and less greedy version of traditional forward selection methods. LAR is described in detail in a paper by Brad Efron, Trevor Hastie, Iain Johnstone and Rob Tibshirani, soon to appear in the Annals of Statistics. The paper, as well as R and Splus packages, are
2007 Jan 06
0
has anyone implemented LARS with the "positive lasso"?
Hi, I am interested in a modification to LARS that allows for positive-only constraints in the variables (with details about how to implement this as described in section 3.4 of the Efron et al (2003) LARS paper). Before I dive into the "lars" package code myself, I was wondering if anyone knew of a version where this is available, or if another package that I have not found can do
2006 Sep 18
0
Propensity score modeling using machine learning methods. WAS: RE: LARS for generalized linear models
There may be benefits to having a machine learning method that explicitly targets covariate balance. We have experimented with optimizing the weights directly to obtain the best covariate balance, but got some strange solutions for simple cases that made us wary of such methods. Machine learning methods that yield calibrated probability estimates should do well (e.g. those that optimize the
2009 Jul 09
0
Apply weights to the Efron Approximation
Dear all, I want to apply weights to my sample data set and I am struggling with the Efron Approximation with weights. I have got one sample data shown as below: customer week arrest fin age race weight 1 weight 2 weight 3 1 20 1 1 27 1 2 15 2 2 17 1 0 18 1 2 19 1 3 25 1 1 19 0 2 20 1 4 52 0 1 23 1 2 5 1 5 52 0 0 19 0 2 11 1 6 25 1 0 19 0 2 26 1 I applied four different weighted Efron
2013 Jun 02
0
Conversión de objeto temporal (TS) a matriz (o data.frame)
Estimado Rubén Gómez Antolí En mi caso en particular al trabajar con fechas, me encontré con inconvenientes, algunos de ellos fueron mejorados en R, hoy estoy desactualizado, pero creo que en el siguiente lugar http://cran.r-project.org/web/views/TimeSeries.html hay referencia actualizada, esperando que en esta encuentre lo que necesite lo saludo muy atentamente. Javier Marcuzzi
2010 Aug 22
1
[LLVMdev] Request information about LLVM for research
Dear Sir, As per request below, I want to use your LLVM project in my thesis and I have no idea where to start and I couldn't find any information about how to build my test programs with your infrastructure and get my required information. Is your tool is a testing tool? Can it accept program and test case as input and output like the input test case is cover which branch and which
2005 Jun 17
1
(PR#7951) DispatchOrEval missing in do_isfinite and do_isinfinite
Hi, OK, if you try to explicitly make them generic, you are told that they are implicitly already generic: > setGeneric("is.finite", function(from, ...) standardGeneric("is.finite")) Error in setGeneric("is.finite", function(from, ...) standardGeneric("is.finite")) : "is.finite" is a primitive function; methods can be defined, but the
2010 Feb 07
1
Out-of-sample prediction with VAR
Good day, I'm using a VAR model to forecast sales with some extra variables (google trends data). I have divided my dataset into a trainingset (weekly sales + vars in 2006 and 2007) and a holdout set (2008). It is unclear to me how I should predict the out-of-sample data, because using the predict() function in the vars package seems to estimate my google trends vars as well. However, I want
2008 Mar 07
0
How to do a time-stratified case-crossover analysis for air pollution data?
Dear Experts, I am trying to do a time-stratified case-crossover analysis on air pollution data and number of myocardial infarctions. In order to avoid model selection bias, I started with a simple simulation. I'm still not sure if my simulation is right. But the results I get from the "ts-case-crossover" are much more variable than those from a glm. Is this: a. Due to
2008 Mar 07
0
How to do a time-stratified case-crossover analysis for air pollution data? Unformatted text-version, with an additional note
Dear Experts, I am trying to do a time-stratified case-crossover analysis on air pollution data and number of myocardial infarctions. In order to avoid model selection bias, I started with a simple simulation. I'm still not sure if my simulation is right. But the results I get from the "ts-case-crossover" are much more variable than those from a glm. Is this: a. Due to the simple
2012 Apr 29
0
need help with avg.surv (Direct Adjusted Survival Curve)
Hello R users,  I am trying to obtain a direct adjusted survival curve. I am sending my whole code (see below). It's basically the larynx cancer data with Stage 1-4. I am using the cox model using coxph option, see the fit3 coxph. When I use the avg.surv option on fit3, I get the following error: "fits<-avg.surv(fit3, var.name="stage.fac", var.values=c(1,2,3,4), data=larynx)
2003 Jun 16
0
new package: eha
A few days ago I uploaded to CRAN a new package called 'eha', which stands for 'Event History Analysis'. Its main focus is on proportional hazards modeling in survival analysis, and in that respect eha can be regarded as a complement and an extension to the 'survival' package. In fact eha requires survival. Eha contains three functions for proportional hazards
2003 Jun 16
0
new package: eha
A few days ago I uploaded to CRAN a new package called 'eha', which stands for 'Event History Analysis'. Its main focus is on proportional hazards modeling in survival analysis, and in that respect eha can be regarded as a complement and an extension to the 'survival' package. In fact eha requires survival. Eha contains three functions for proportional hazards
2004 Dec 16
0
fitting problems in coxph.fit
Dear Thomas & Dear List, the fitting function `coxph.fit' called by `coxph' may fail to estimate the regression coefficients when some values of the design matrix are very large. For example library(survival) ### load example data load(url("http://www.imbe.med.uni-erlangen.de/~hothorn/coxph_fit.Rda")) method <- "efron" ### copied from `coxph.fit' coxfit
2004 Jun 08
0
bootstrap: stratified resampling
Dear All, I was writing a small wrapper to bootstrap a classification algorithm, but if we generate the indices in the "usual way" as: bootindex <- sample(index, N, replace = TRUE) there is a non-zero probability that all the samples belong to only one class, thus leading to problems in the fitting (or that some classes will end up with only one sample, which will be a problem
2012 Apr 30
0
need help with avg.surv (Direct Adjusted Survival Curve), Message-ID:
Well, I would suggest using the code already in place in the survival package. Here is my code for your problem. I'm using a copy of the larynx data as found from the web resources for the Klein and Moeschberger book. larynx <- read.table("larynx.dat", skip=12, col.names=c("stage", "time", "age", "year",
2010 Sep 08
4
coxph and ordinal variables?
Dear R-help members, Apologies - I am posting on behalf of a colleague, who is a little puzzled as STATA and R seem to be yielding different survival estimates for the same dataset when treating a variable as ordinal. Ordered() is used to represent an ordinal variable) I understand that R's coxph (by default) uses the Efron approximation, whereas STATA uses (by default) the Breslow. but we