Hi,
I am also looking to verify the vendor-libs being used.
What does numpy.__config__.show() tell you ?
In the case of the ACML compilation, I get: 0 u0050015@lo-03-02 .../u0050015 $ python -c "import numpy; numpy.show_config()" atlas_threads_info: libraries = ['lapack', 'acml', 'python2.4'] library_dirs = ['/apps/prod/python/2.4.3/lib'] language = f77 blas_opt_info: libraries = ['acml', 'python2.4'] library_dirs = ['/apps/prod/python/2.4.3/lib'] define_macros = [('NO_ATLAS_INFO', 2)] language = c atlas_blas_threads_info: libraries = ['acml', 'python2.4'] library_dirs = ['/apps/prod/python/2.4.3/lib'] language = c lapack_opt_info: libraries = ['lapack', 'acml', 'python2.4'] library_dirs = ['/apps/prod/python/2.4.3/lib'] define_macros = [('NO_ATLAS_INFO', 2)] language = f77 lapack_mkl_info: NOT AVAILABLE blas_mkl_info: NOT AVAILABLE mkl_info: NOT AVAILABLE In the case of a more standard installation (blas/lapack/atlas) I guess this might give some extra information, but as I understand these are just the paths to the libraries that were used at compile time. If show_config() in your case does not show your lapack dir, I am afraid you are not using them as they were not found during compilation. In order to use ACML I had to use a custom site.cfg (which basically says what show_config() now reports), so I wanted some kind of extra verification that the installation is fine. My confusion actually comes from the fact that importing _dotblas in my installation results in undefined references. Yet the timings of numpy.dot seem ok, so 'some' optimized library is used, it is just not clear which one. 0 u0050015@lo-03-02 .../core $ pwd /data/home/u0050015/inst/lib/python2.4/site-packages/numpy/core 0 u0050015@lo-03-02 .../core $ python -c "import _dotblas" Traceback (most recent call last): File "<string>", line 1, in ? ImportError: /apps/prod/python/2.4.3/lib/libacml.so: undefined symbol: vcosf Regards, YVES