[Numpy-discussion] The value of a native Blas
Chris Barker
Chris.Barker at noaa.gov
Thu Jul 29 12:01:05 CDT 2004
Hi all,
I think this is a nifty bit of trivia.
After getting my nifty Apple Dual G5, I finally got around to doing a
test I had wanted to do for a while. The Numeric package uses LAPACK for
the Linear Algebra stuff. For OS-X there are two binary versions
available for easy install:
One linked against the default, non-optimized version of BLAS (from Jack
Jansen's PackMan database)
One linked against the Apple Supplied vec-lib as the BLAS. (From Bob
Ippolito's PackMan database (http://undefined.org/python/pimp/)
To compare performance, I wrote a little script that generates a random
matrix and vector: A, b, and solves the equation: Ax = b for x
N = 1000
a = RandomArray.uniform(-1000, 1000, (N,N) )
b = RandomArray.uniform(-1000, 1000, (N,) )
start = time.clock()
x = solve_linear_equations(a,b)
print "It took %f seconds to solve a %iX%isystem"%(
time.clock()-start, N, N)
And here are the results:
With the non-optimized version:
It took 3.410000 seconds to solve a 1000X1000 system
It took 28.260000 seconds to solve a 2000X2000 system
With vec-Lib:
It took 0.360000 seconds to solve a 1000X1000 system
It took 2.580000 seconds to solve a 2000X2000 system
for a speed increase of over 10 times! Wow!
Thanks Bob, for providing that package.
I'd be interested to see similar tests on other platforms, I haven't
gotten around to figuring out how to use a native BLAS on my Linux box.
-Chris
--
Christopher Barker, Ph.D.
Oceanographer
NOAA/OR&R/HAZMAT (206) 526-6959 voice
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Chris.Barker at noaa.gov
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