Hi, if a striped down version of t.test is required for speed, before implementing a rewrite I would check out the multtest Bioconductor package.
It takes a fraction of a second to do 56000 t-tests on a 2.4 Ghz PIV. dim(X) [1] 56000 4 pcols <- 4 replicates <- rep(0:1, each=2) unix.time({tscores <- mt.teststat(X, classlabel=replicates, test="t.equalvar") dfs <- pcols - 2 pvalues <- 2*(1-pt(abs(tscores), df=dfs))}) [1] 0.21 0.05 0.26 0.00 0.00 > length(pvalues) [1] 56000 Check out ?mt.teststat and its test argument options. Marcus >>> "Jagarlamudi, Choudary" <[EMAIL PROTECTED]> 17/03/2005 7:16:13 a.m. >>> Thanks to everyone who posted on this topic. I tried apply() as Ramasamy had suggested and it took 40 seconds on my machine. The for loop however took over 4 minutes and i gave up. I am going to strip the t.test function and write it as suggested by Andy. Hope that will be the quickest. Once again thank you for all who have posted on this. Choudary Jagarlamudi Instructor Computer Science Southwestern Oklahoma State University STF 254 100 campus Drive Weatherford OK 73096 Tel 580-774-7136 [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________________ The contents of this e-mail are privileged and/or confidenti...{{dropped}} ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html