similar to: Documentation of colSums et. al (PR#4154)

Hi, all! My project today is to write a speedy colSums(), which is a function available in S-Plus to add the columns of a matrix. Here are 4 ways to do it, with the time it took (elapsed, best of 3 trials) in both R and S-Plus: m <- matrix(1, 400, 40000) x1 <- apply(m, 2, sum) ## R=16.55 S=52.39 x2 <- as.vector(rep(1,nrow(m)) %*% m) ## R= 2.39 S= 8.52 x3 <-

For your consideration: > z [,1] [,2] [1,] 1 NA [2,] 2 NA [3,] 3 NA > colSums(z) [1] 6 NA Correct, according to the documentation > colSums(z,na.rm=T) [1] 6 0 Surprising to me, but, as documented, correctly consistent with apply() and >sum(NULL) [1] 0 The documentation for sum() explicitly notes that the sum of an empty set is 0 by definition, so that users

Hi, This report deals with p-values coming from chisq.test using the simulate.p=TRUE option. The issue is numerical accuracy and was brought up in previous bug reports 3486 and 3896. The bug was considered fixed but apparently was only mostly fixed. Just the typical problem of two values that are mathematically equal not ending up numerically equivalent. Consider this series of three 2x2

I need to calculate a large number of t statistics, and would like to do so via matrix operations. So far I have figured out a way to calculate the mean of each row of the matrix: d <- matrix(runif(100000,1,10), 1000, 10) # some test data s <- rep(1,ncol(d)) # a sum vector to use for matrix multiplication means <- (d%*%s)/ncol(d) This is at least 1 order of magnitude faster than

Hi people, If there is a fn "colMeans" why isn't there a "colSDs" etc Thanks, Phil. -- Philip Rhoades Pricom Pty Limited (ACN 003 252 275) GPO Box 3411 Sydney NSW 2001 Australia Mobile: +61:0411-185-652 Fax: +61:2:8923-5363 E-mail: pri at chu.com.au -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read

Hi, I'm wondering if anyone can point me to a function that will allow me to do a ranking that treats ties differently than rank() provides for? I'd like a method that will assign to the elements of each tie group the largest rank. An example: For the vector 'v', I'd like the method to return 'rv' v: 1 2 3 3 3 4 5 5 6 7 rv: 1 2 5 5 5 6 8 8 9 10 Thanks,

Is it possible to compute the variance of every column in a matrix without a loop? -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch

Hi, I'm using colSums and rowSums to sum the first dimensions of arrays. It works ok but the resulting object is different. See > a3d <- array(rnorm(120, mean=2), dim=c(20,6,1)) > dim(colSums(a3d)) [1] 6 1 > dim(rowSums(a3d)) NULL > class(colSums(a3d)) [1] "matrix" > class(rowSums(a3d)) [1] "numeric" I was expecting rowSums to preserve the array

Mark Leeds <mleeds at mlp.com> wrote (to S-News): > does anyone know the R equivalent of the SPlus rowVars function ? Andy Liaw <andy_liaw at merck.com> replied: > More seriously, I seem to recall David Brahms at one time had created an R > package with these dimensional summary statistics, using C code. (And I > pointed him to the `two-pass' algorithm for variance.)

Hi, It would be great if someone would add write.delim() as an adjunct to write.table(), just as with write.csv(). I store a lot of data in tab-delimited files and can read it in easily with: read.delim("text.txt", as.is=TRUE) and would love to be able to write it out as easily when I create these files. The obvious setting needed for write.delim() is sep = "\t", but in

Full_Name: Doug Grove Version: 2.3.1 patched (2006-07-03 r38485) OS: Windows Submission from: (NULL) (24.19.37.159) A msg. to R-help prompted me to read the help page for split.screen/screen, etc. I understand what the function is for, but could not find information that described how the argument 'n' in screen/erase.screen/close.screen is mapped to the regions on the device. All we

Full_Name: Doug Grove Version: 2.10.0 10-26-2009 OS: x86_64-unknown-linux-gnu Submission from: (NULL) (140.107.164.65) Hi, Looks like the revisions to help.search didn't get completely finished. When the user specifies the argument 'package' the code doesn't define the variable 'paths' prior to trying to use it, which obviously produces an error. The code dies when

Hi, I'm trying to understand a behaviour that I have encountered and can't fathom. Here's some code I will use to illustrate the behaviour: # start with some data frame "a" having some named columns a <- data.frame(a=rep(1,3),c=rep(2,3),d=rep(3,3),e=rep(4,3)) # create a subset of the original data frame, but include a # name "b" that is not present in my

Full_Name: Doug Grove Version: R.1.9.1 OS: Linux Submission from: (NULL) (140.107.156.61) I just found that rank() has a 'decreasing' argument that is not documented in its help page. I checked my version of 2.0.0 (original release hence unpatched) and it is not documented there. For curiousity I also went back to version 1.8.1 and checked the function (not the documentation)and at

Hi, I'm having what I believe are OS problems with my installation of R-1.6.0. The machine I'm using was previously running R-1.4.0. The install seemed fine to me. I didn't note an error messages in 'make' or 'make check'. My problem is that I've been running some memory intesive code, and the code that ran under 1.4.0 but won't run under R.1.6.0 (or under

I've uploaded a package colSums_1.0.tar.gz to CRAN /src/contrib/Devel. It contains functions colSums, colMeans, colVars, colStdevs, rowSums, rowMeans, rowVars, and rowStdevs. These do simple, fast arithmetic on columns/rows of a matrix, or more generally across dimensions of an array, e.g. colSums(m) = apply(m, 2, sum) but faster. They should be compatible with the corresponding S-Plus

I sent a message to <r-announce at stat.math.ethz.ch> last Thursday ("New package: colSums"), and still haven't seen it echoed on r-help or on the web archive (in fact there is no r-announce web archive for 2002). Is something broken? Did I need to use <r-announce at lists.R-project.org> instead? -- -- David Brahm (brahm at alum.mit.edu)

Hi, all, I've been converting code from S-Plus ("S" for short) to R for a few weeks. Here are some differences I've found, aside from the big well-known ones (scoping, models, data storage) and the contents of Kurt Hornik's FAQ section 3.3.3. Let me start with the ones that seem like serious bugs or deficiencies: 1) LETTERS[c(NA,2)] in S is

Hi, all, I've been converting code from S-Plus ("S" for short) to R for a few weeks. Here are some differences I've found, aside from the big well-known ones (scoping, models, data storage) and the contents of Kurt Hornik's FAQ section 3.3.3. Let me start with the ones that seem like serious bugs or deficiencies: 1) LETTERS[c(NA,2)] in S is

Hi, I have a matrix, say m=matrix(c( 983,679,134, 383,416,84, 2892,2625,570 ),nrow=3 ) i can find its row/col sum by rowSums(m) colSums(m) How do I divide each row/column by its rowSum/colSums and still return in the matrix form? (i.e. the new rowSums/colSums =1) Thanks. Casper -- View this message in context: