[Numpy-discussion] performance matrix multiplication vs. matlab

[Xue (Sue) Yang]

Hi,

I followed what I collected about installation of numpy with lapack and
atlas and installed numpy on our desktop with RHEL4 and 4 cores.

>uname -a

Linux curie.physics.usyd.edu.au 2.6.9-89.0.15.ELsmp #1 SMP Sat Oct 10
05:59:16 EDT 2009 i686 i686 i386 GNU/Linux

I successfully installed lapack-3.1.1, atlas3.8.0 with fortran comfiler:
gfortran, and numpy-1.3.0 with enthought-python distribution (python2.5).

> python
>>import numpy
>>a = numpy.random.randn(6000, 6000)
>>numpy.dot(a, a)

Surprisingly, it only uses 2 cores instead of 4 cores.  Where and how should
I set up the number of threads for numpy?

Thanks!

Dr. Xue (Sue) Yang
School of Physics, University of Sydney
Ph: 02 9351 6081
Email: x.yang@physics.usyd.edu.au