Message-ID: <20294.30690.852050.817960@max.nulle.part>
Date: 2012-02-23T17:31:14Z
From: Dirk Eddelbuettel
Subject: Accessto OpenBLAS
In-Reply-To: <1330016908.67438.YahooMailNeo@web120601.mail.ne1.yahoo.com>
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