Mark, > > To the extent that it may be helpful here and I can do more if need be, I > built 32 bit R 2.12.0 patched on Snow Leopard (10.6.4), using the R BLAS > rather than Apple's veclib. This is on an early 2009 17" MBP with a 2.93 Ghz > Core 2 Duo (MacBookPro5,2) and 4Gb of RAM. > > Based upon Doug's comment in this thread that the issue may be related to the > use of Apple's veclib BLAS, as opposed to R's reference BLAS, I ran some > tests. > > My config includes: > > --without-blas --without-lapack > > just to be sure that the above is the correct invocation, based upon what I > found online. > > Using this build, with all CRAN packages freshly installed using this build, > I ran the example used here with lme4 0.999375-35. I get: > > library(lme4) > y <- (1:20)*pi; x <- (1:20)^2;group <- gl(2,10) > M2. <- lmer (y ~ 1 + x + (1 + x | group)) > M2 <- lmer (y ~ x + ( x | group)) > >> identical(fixef(M2), fixef(M2.)) > [1] TRUE > > > > I then created a function so that I could use replicate() to run this test a > "larger" number of times: > > testlme4 <- function() > { > y <- (1:20)*pi; x <- (1:20)^2;group <- gl(2,10) > M2. <- lmer (y ~ 1 + x + (1 + x | group)) > M2 <- lmer (y ~ x + ( x | group)) > identical(fixef(M2), fixef(M2.)) > } > > > RES <- replicate(1000, testlme4()) > >> all(RES) > [1] TRUE > >> table(RES) > RES > TRUE > 1000 > > Does the example need to be run a "very large" number of times to be sure > that it does not fail, or is the above a reasonable indication that the use > of R's BLAS is a more appropriate default option for R on OSX? If I am not > mistaken (and somebody correct me if wrong), R's BLAS is the default on > Windows and Linux (from my recollections on Fedora). Why should OSX be > different in that regard?
Thanks for the very informative post. I added R-Mac in my reply to see if someone can come up with a response to your query. It would also be interesting to know if it were possible to switch the OSX R binary to use the R BLAS library. > > Also, as an aside to Federico, I use 32 bit R on OSX largely because I have > to interact with an Oracle server via RODBC. The only ODBC drivers available > for Oracle on OSX are 32 bit and they are not compatible with 64 bit R. It > would be rather cumbersome when running reports (via Sweave) to first extract > the data in 32 bit R and then switch to 64 bit R to run the reports. I can > run it all in a single step using 32 bit R. I also do not have a need for the > larger memory address space afforded by 64 bit R. I'm very primitive in any integration between R and anything else, so much so that I abandoned Emacs (well integrated with R) for Vim (not as well integrated). On the other hand I do need the greater memory address space of R64. I understand my needs and habits are not universally shared, but, if the *only* reason for using R32 vs R64 is the 20% speed difference, I'd use R64 for running lme4. Best, Federico -- Federico C. F. Calboli Department of Epidemiology and Biostatistics Imperial College, St. Mary's Campus Norfolk Place, London W2 1PG Tel +44 (0)20 75941602 Fax +44 (0)20 75943193 f.calboli [.a.t] imperial.ac.uk f.calboli [.a.t] gmail.com _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-mac