similar to: Why no colSDs etc

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

I am using the R 2.2.1 in a Windows XP environment. I have a dataframe with 12 columns and 1,000 rows. (Some of the rows have 1 or fewer values.) I am trying to use rowVars to calculate the variance of each row. I am getting the following message: ?Error in na.remove.default(x) : length of 'dimnames' [1] not equal to array extent? Is there a good work-around?

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

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, Currently, the "base" has colSums, colMeans. It seems that it would be useful to extend this to also include colMin, colMax (of course, rowMin and rowMax, as well) in order to facilitate faster computations for large vectors (compared to using apply). Has this been considered before? Please forgive me if this has already been discussed before. Thanks, Ravi Ravi Varadhan, Ph.D.

Hi together, I have some data in a matrix structure - say 1000 rows with 10 columns. And I like to do some calculations (like max, avg or min) on row level. The only solution I found so fare was using a loop like for (i in 1:1000) { max[i] <- max(matrix[I,]) } It looks like that this is not very fast. Does an other way exists? Kind regards Ulrich

Hi. I am trying to use the linear optimizer from package lpSolve in R 2.4.1 on Windows XP (Version 5.1). The problem I am trying to solve has 2843 variables (2841 integer, 2 continuous) and 8524 constraints, and I have 2 Gb of memory. After I load the input data into R, I have at most 1.5 Gb of memory available. If I start the lp with significantly less memory available (say 1 Gb), I get

Hi. I have defined a function, f1, that calls another function, f2. Inside f1 an intermediate variable called nm1 is created; it is a matrix. f2 takes a matrix argument, and I defined f2 (schematically) as follows: f2<-function(nmArg1=nm1,...){nC<-ncol(nmArg1); ... } so that it expects nm1 as the default value of its argument. f1 is defined (schematically) as:

People, My backup script has lines: dt=`date ''+%Y%m%d''` . . DELETE="--delete" . . rsync -av $DELETE --backup --backup-dir /delmod/$dt /etc /backup/ rsync -av $DELETE --backup --backup-dir /delmod/$dt /root /backup/ - only the changes to /root get backed up but ALL of /etc gets backed up everytime! - why should this happen? Thanks, Phil. -- Philip Rhoades

I've posted a sample file for estimating loglinear models for square tables (mobility models) at http://www.xs4all.nl/~jhckx/mcl/R/ Comments and suggestions are welcome. John Hendrickx

Dear group, I have a matrix like the following: Name Sample1 sample2 sample3 sample4 ..... sample(n) nm1 10.5 13.5 30 31 nm2 8 11 34 29 nm3 9 10.3 27.8 35 nm(j) I want to be able to calculate correlation between all pairs of names. For example (nm1,nm2),

Hello, everybody Say I have nm1 <- c(rep(1,10), rep(0,10)) then I can do: diff(nm1) to see where I have shift in value but what if I have nm2 <- c(rep("SPZ8", 10), rep("SPX9", 10)) how can I produce the same ouput as diff(nm1) does, that is zeros everywhere except for one place where SPZ8 changes to SPX9 (there should be 1 there)? What if I have a matrix of characters

Hi, I have what I think is an easy question. I have a data frame, called stockdata, of stock prices that looks like this: date ticker close 1 01/02/1998 GE 24.667 2 01/05/1998 GE 25.104 3 01/06/1998 GE 24.771 4 01/07/1998 GE 24.979 5 01/08/1998 GE 24.750 6 01/02/1998 HIT 71.125 7 01/05/1998 HIT 72.313

Hello, colnames seems to be not optimized well for data.frame. It escapes processing for data.frame in if (is.data.frame(x) && do.NULL) return(names(x)) but only when do.NULL true. This makes huge difference when do.NULL false. Minimal edit to `colnames`: if (is.data.frame(x)) { nm <- names(x) if (do.NULL || !is.null(nm)) return(nm) else

Hi all, I want to use a fourth plot on a page as a "map" of how to interpret the previous three plots - so the x axes are all the same but I want the y axis on the fourth plot to have no graduations or numbers - is this possible? I had a look in Peter's book and the help stuff but couldn't see anything. Thanks, Phil. -- Philip Rhoades Pricom Pty Limited (ACN 003 252

Dear R friends I wanted a function to make a simple percent table that would be easy for students to use. The goal originally was to have a simple thing people would call like this pctable(rowvar, colvar, data) and the things "rowvar" and "colvar" might be names of variables in data. I wanted to avoid the usage of "with" (as we now see in the table help). Then

Dear Listers: I used cronbach{psy} to evaluate the internal consistency and some set of variables gave me alpha=-1.1003, while other, alpha=-0.2; alpha=0.89; and so on. I am interested in knowing how to interpret 1. negative value 2. negative value less than -1. I also want to re-mention my previous question about how to evaluate the consistency of a set of variables and about the total

So I''m updating multiple model objects in one go with something like this in my controller: => Photo.update(params[:photo].keys, params[:photo].values) When the update fails due to validation errors, how do I detect it? The Rails API says: "If the save fails under validations, the unsaved object is still returned." So I can''t simply do this: => if

People, I didn''t get an answer to this before so I am trying again: I could change an existing "policy" table to "policies" with no drama but the are a number of related tables ie: p_2quot p_addr p_cc p_cs p_direct p_div p_exss

People, I want to create seven plots on the one graph - each with it's own Y axis and scale - I want the plots overlaid because it is the shape of the graphs that I want to compare, not so much the values. I have found examples where people show how to put two Y axes on the left of the plot but I couldn't find examples of any more than that - is it possible? Thanks, Phil. --