search for: ramasamy

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2005 Jul 25
passing formula arguments cv.glm
...quot;formu" not found I think this has something to do with formula and environments but I do not know enough to solve it myself. I searched the archive without much help (perhaps I was using the wrong keywords). Any help would be very much appreciated. Thank you. Regards, -- Adaikalavan Ramasamy ramasamy at Centre for Statistics in Medicine Wolfson College Annexe Tel : 01865 284 408 Linton Road, Oxford OX2 6UD Fax : 01865 284 424
2005 Feb 25
display full form in args
Forgive me for I do not fully comprehend the idea of classes and methods but I was wondering if someone could help explain why the function args () behaves the way it does. Why does args(cut) show the simplified version instead of the more complete one as in help("cut"). This is true for few other functions (e.g. plot, rep). > args(cut) function (x, ...) Sometime I can get
2008 Aug 24
howto optimize operations between pairs of rows in a single matrix like cor and pairs
Hi, I calculating the output of a function when applied to pairs of row from a single matrix or dataframe similar to how cor() and pairs() work. This is the code that I have been using: pairwise.apply <- function(x, FUN, ...){ n <- nrow(x) r <- rownames(x) output <- matrix(NA, nc=n, nr=n, dimnames=list(r, r)) for(i in 1:n){ for(j
2002 Jul 15
meaning of error message about collinearity
.... Even then you still have 80 variances to estimate. Besides, I don't think lda() does that. If you really have to discrinimate 40 data points with 80 variables, use methods that do not rely on the estimation of covariance matrix. Andy > -----Original Message----- > From: Adaikalavan Ramasamy [mailto:ramasamy at] > Sent: Friday, July 12, 2002 4:08 PM > To: r-help at; allstat at > Subject: [R] meaning of error message about collinearity > > > Just a quick question. I am trying to fit an LDA model with a > restricted >...
2005 Aug 15
stepAIC invalid scope argument
I am trying to replicate the first example from stepAIC from the MASS package with my own dataset but am running into error. If someone can point where I have gone wrong, I would appreciate it very much. Here is an example : set.seed(1) df <- data.frame( x1=rnorm(1000), x2=rnorm(1000), x3=rnorm(1000) ) df$y <- 0.5*df$x1 + rnorm(1000, mean=8, sd=0.5) # pairs(df); head(df) lo <-
2005 Sep 02
C-index : typical values
I am doing some coxPH model fitting and would like to have some idea about how good the fits are. Someone suggested to use Frank Harrell's C-index measure. As I understand it, a C-index > 0.5 indicates a useful model. I am probably making an error here because I am getting values less than 0.5 on real datasets. Can someone tell me where I am going wrong please ? Here is an example using
2005 Jul 10
Boxplot in R
I am trying to draw a plot like Matlab does: The upper extreme whisker represents 95% of the data; The upper hinge represents 75% of the data; The median represents 50% of the data; The lower hinge represents 25% of the data; The lower extreme whisker represents 5% of the data. It looks like: --- 95% | | ------- 75% | | |-----| 50% | | | | -------
2002 Aug 12
Attaching marginal summary plots to the main matrix plot
...ple does pretty much what you're asking about (with a scatterplot and histograms, but the idea should be the same). Hope this helps, Matthew Wiener Applied Computer Science & Mathematics Dept. Merck Research Labs Rahway, NJ 07090 732-594-5303 -----Original Message----- From: Adaikalavan Ramasamy [mailto:ramasamy at] Sent: Monday, August 12, 2002 5:27 AM To: r-help at Subject: [R] Attaching marginal summary plots to the main matrix plot Dear helplist, I am trying to visualise a datamatrix together with its marginal densities. Suppose dat <- matrix( rnor...
2004 Jul 16
Does AIC() applied to a nls() object use the correctnumber of estimated parameters?
...logLik(lm1) + 2*(length(coef(lm1))+1) [1] 326.0716 attr(,"nall") [1] 47 attr(,"nobs") [1] 47 attr(,"df") [1] 7 attr(,"class") [1] "logLik" I thought the same would have held for nls() objects. > -----Original Message----- > From: Adaikalavan Ramasamy [mailto:ramasamy at] > Sent: Friday, 16 July 2004 1:14 PM > To: Caley, Peter (Entomology, Black Mountain) > Cc: R-help > Subject: Re: [R] Does AIC() applied to a nls() object use the > correctnumber of estimated parameters? > > > I do not know anything abou...
2007 May 20
optional fields in function declarations; Solved
...ction as above the operator must of course input all the variables. Finally I could fix as follow. > log_raise=function(num, exp=2, base=exp){return(log(num^exp,base))} thank you helps, cheers Claudio Patrick Burns ---------- Initial Header ----------- >From : "Adaikalavan Ramasamy" ramasamy at To : " at" at Cc : "r-help" r-help at Date : Sun, 20 May 2007 00:21:32 +0100 Subject : Re: [R] optional fields in function declarations > Can you provide a...
2005 Aug 08
use different symbols for frequency in a plot
suppose I have the following data x<-c(rep(.1,5),rep(.2,6),rep(.4,10),rep(.5,20)) y<-c(rep(.5,3),rep(.6,8),rep(1.2,8),rep(2.5,18),rep(3,4)) If I plot(x,y) in R, I will only get seven distinct points. What I want to do is to use different symbols to show the frequency at each point. e.g. if the frequncey is between 1 and 5, then I plot the point as a circle; if the frequency is between 6
2002 Sep 02
Coplot graph size manipulation
I am currently plotting a graph with the function coplot() conditional on two factors which gives me 36 sub-panels. I have a few questions in general about changing the size of the graph. My question follows : a) I have a fair bit of text to put on the margin sides using mtext(). What is the best way to shrink the whole graph to say 80 - 90% so that I can include a bit more words. b) Since I am
2004 Nov 04
(no subject)-about the waring/errors in ks.test
...t), and sometimes shows up as > waring when I typed warning() (in most cases the group > I am testing is relatively large). But all the data > are from the same data set. > So what is the distinction between these two? > Many thanks, > > Fang > > > --- Adaikalavan Ramasamy <ramasamy at> > wrote: > > > Reading the posting guide will tell you (among other > > things) to : > > a) use a sensible subject line > > b) give a reproducible example when possible > > > > See other comments below. > > >...
2008 Sep 17
unix-type commandline keystrokes in the windows RGUI
Hi all, I am generally quite fond of the unix commandline keystrokes (e.g. searching back in your history with [CTRL]-R, and cutting/pasting with [CTRL]-K/Y) which work in the R commandline in *nix. Does anyone know if there's any way to get similar functionality in the Windows RGUI? I know that as of now, [CTRL]-A and -E do the same as unix (beginning and end of line) and [CTRL]-Y
2006 Feb 21
How to Import Data
Hello, I am a very new user of R. I've spent several hours trying to import data, so I feel okay asking the list for help. I had an Excel file, then I turned it into a "csv" file, as instructed by directions. My filename is "x111.csv." I then used the following commands to read this (fairly small) dataset in. x111 <-read.table(file='x111.csv',
2002 Aug 01
copying objects
Hello, How does one copy objects between Workspaces? Thank you, Deborah -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at
2008 Aug 25
Maintaining repeated ID numbers when transposing with reshape
I have a dataset in "long" format that looks something like this: ID TEST RESULT 1 A 17 1 A 12 1 B 15 1 C 12 2 B 8 2 B 9 Now what I would like to do is transpose it like so: ID TEST A TEST B TEST C 1 17 15 12 1 12 . . 2
2005 Feb 28
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
2002 Jul 26
Parzen Windows
...ailable at one time in ksmooth() in S(plus). Cheers, Andy > From: ripley at [mailto:ripley at] > > Parzen windows is an engineer's term for kernel density estimation. > So, see packages KernSmooth, sm, .... > > On Fri, 26 Jul 2002, Adaikalavan Ramasamy wrote: > > > Does anyone know if there is a function in R that fits a > Parzen Window ? > > > > I have searched the mail archives and the packages to no > avail. Perhaps it > > has a different name or implemented differently. I do not > mind trying to > &g...
2003 Feb 09
Clustering partition and memory
Dear R-help list members i would like to use R to produce clustering or partitioning of a dataset. I am trying to use the functions: - hierclust() of the package multiv -pam(), agnes() and fanny() of the package cluster But I cannot get any result because of lack of memory. Would you know any clustering function not to greedy in memory? I have tried to expand my memory limit with memory.limit()