So I was passing this to my IT department but they have now abandoned me and I'm left to fend for myself. I guess I have to learn how to do everything on my own now.
I looked at the read.me. It's pretty cryptic. How does one link with -lopenblas to a shared library? At the bash command line? Somewhere else? Where? My machine has 4 Intel® Xeon® Processor X5650 CPUs. On Intel's site they say each CPU has 6 cores and 12 threads. Of course I want to take advatage of that horsepower. It looks like the environment variables can be setup when I launch R, correct? The questions is how? There are three environment variables. Which one should I use? And how do I get R to pick up those environment variables. (I'm usinf Rkward as a front end). There's some ambiguity in the read.me under known issues. It says: The number of CPUs/Cores should less than or equal to 8*sizeof(unsigned long). On 64 bits, the limit is 64. I'm not sure what that implies in terms of my machine. To what values do I set my environment variables? ----- Original Message ----- From: Dirk Eddelbuettel <[email protected]> To: Scott Raynaud <[email protected]> Cc: "[email protected]" <[email protected]> Sent: Thursday, February 23, 2012 11:31 AM Subject: Re: [R-sig-Debian] Accessto OpenBLAS On 23 February 2012 at 09:08, Scott Raynaud wrote: | So my experiments have confirmed that the binary version of | OpenBLAS uses onlt two cores. Should the compiled version | use more? | | I want figure out which package to utilize mulitiple cores in | a UNIX environment. Did some research on this a while back | but it's a bit fuzzy right now. My main concern is there's a | warning about BLAS and multiple cores in the install docs. | Will I run into problems? Did you see the README? 4.Usages Link with libopenblas.a or -lopenblas for shared library. 4.1 Set the number of threads with environment variables. for example, export OPENBLAS_NUM_THREADS=4 or export GOTO_NUM_THREADS=4 or export OMP_NUM_THREADS=4 The priorities are OPENBLAS_NUM_THREADS > GOTO_NUM_THREADS > OMP_NUM_THREADS. If you compile this lib with USE_OPENMP=1, you should only set OMP_NUM_THREADS environment variable. Some BLAS libraries can respond to environment variables at run-time: MKL, GotoBlas and hence OpenBlas. For others such as Atlas this is fixed at compile time. Dirk -- "Outside of a dog, a book is a man's best friend. Inside of a dog, it is too dark to read." -- Groucho Marx _______________________________________________ R-SIG-Debian mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-debian
