[Numpy-discussion] Dot product performance on python 2.6 (windows)

["V. Armando Solé"]

David Cournapeau wrote:
> V. Armando Solé wrote:
>   
>> Hello,
>>
>> I have found performance problems under windows when using python 2.6
>> In my case, they seem to be related to the dot product.
>>
>> The following simple script:
>>
>> import numpy
>> import time
>> a=numpy.arange(1000000.)
>> a.shape=1000,1000
>> t0=time.time()
>> b=numpy.dot(a.T,a)
>> print "Elapsed time = ",time.time()-t0
>>
>> reports an "Elapsed time" of 1.4 seconds under python 2.5 and 15 seconds 
>> under python 2.6
>>
>> Same version of numpy, same machine, official numpy installers for 
>> windows (both with nosse flag)
>>   
>>     
>
> Could you confirm this by pasting the output of numpy.show_config() in
> both versions 
The output of:

python -c "import numpy; import sys; print 
sys.executable;numpy.show_config()" > python26.txt

and

python -c "import numpy; import sys; print sys.executable; 
numpy.show_config()" > python25.txt

are identical except for the first line:

diff python25.txt python26.txt
1c1
< C:\Python25\python.exe
---
 > C:\Python26\python.exe

I paste the python26.txt because the other one is the same except for 
the first line:

C:\Python26\python.exe
blas_info:
    libraries = ['blas']
    library_dirs = ['C:\\local\\lib\\yop\\nosse']
    language = f77

lapack_info:
    libraries = ['lapack']
    library_dirs = ['C:\\local\\lib\\yop\\nosse']
    language = f77

atlas_threads_info:
  NOT AVAILABLE

blas_opt_info:
    libraries = ['blas']
    library_dirs = ['C:\\local\\lib\\yop\\nosse']
    language = f77
    define_macros = [('NO_ATLAS_INFO', 1)]

atlas_blas_threads_info:
  NOT AVAILABLE

lapack_opt_info:
    libraries = ['lapack', 'blas']
    library_dirs = ['C:\\local\\lib\\yop\\nosse']
    language = f77
    define_macros = [('NO_ATLAS_INFO', 1)]

atlas_info:
  NOT AVAILABLE

lapack_mkl_info:
  NOT AVAILABLE

blas_mkl_info:
  NOT AVAILABLE

atlas_blas_info:
  NOT AVAILABLE

mkl_info:
  NOT AVAILABLE

Any hint?

Armando