> From: Douglas Bates > > How does the Opteron perform on floating point? Can you try something > like > > > mm = matrix(rnorm(1e6), nc = 1e3) > > system.time(crossprod(mm)) > [1] 0.51 0.02 0.53 0.00 0.00 > > system.time(crossprod(mm)) > [1] 0.37 0.03 0.40 0.00 0.00 > > system.time(crossprod(mm)) > [1] 0.38 0.02 0.40 0.00 0.00 > > system.time(crossprod(mm)) > [1] 0.38 0.02 0.40 0.00 0.00 > > (That was with R compiled to use Goto's BLAS on a 2.0 GHz P4.) > > Are you using Goto's BLAS or Atlas?
I managed to link R against Goto's BLAS for Opteron (see below). The result looks like: > mm = matrix(rnorm(1e6), nc = 1e3) > system.time(crossprod(mm)) [1] 0.5 0.0 0.5 0.0 0.0 > system.time(crossprod(mm)) [1] 0.39 0.00 0.39 0.00 0.00 > system.time(crossprod(mm)) [1] 0.39 0.01 0.39 0.00 0.00 On the dual 2.4GHz Xeon (using libgoto_p3_512-r0.6.so), I get: > mm = matrix(rnorm(1e6), nc=1e3) > system.time(crossprod(mm)) [1] 0.91 0.01 0.93 0.00 0.00 > system.time(crossprod(mm)) [1] 0.82 0.02 0.84 0.00 0.00 > system.time(crossprod(mm)) [1] 0.83 0.02 0.85 0.00 0.00 We have not found the Opteron to be faster than the Xeon, but the Xeon does have faster RAM... [What I did to link R against Goto's BLAS (mostly following Prof. Bates' instruction): - Install libgoto*.so and symlink to libgoto.so. - Download xerbla.f and compile to xerbla.o. - Run the R configure script with --with-blas="-lgoto /path/to/xerbla.o". - Edit Makeconf and delete the path to xerbla.o in BLAS_LIB. - make; make check ] A bit of gripe about the SUSE ES8 that was pre-loaded on the Opteron: - VNC segfault out-of-box. Needed to purchase maintanence contract to get update that fixed it. - No teTeX, so can't build R manuals in pdf. - No XEmacs (but does have GNU Emacs). Best, Andy ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
