How to check BLAS/LAPACK linkage in NumPy and SciPy?

I am builing my numpy/scipy environment based on blas and lapack more or less based on this walk through.

When I am done, how can I check, that my numpy/scipy functions really do use the previously built blas/lapack functionalities?

Answers:

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Method 1

The method numpy.show_config() (or numpy.__config__.show()) outputs information about linkage gathered at build time. My output looks like this. I think it means I am using the BLAS/LAPACK that ships with Mac OS.

>>> import numpy as np
>>> np.show_config()

lapack_opt_info:
    extra_link_args = ['-Wl,-framework', '-Wl,Accelerate']
    extra_compile_args = ['-msse3']
    define_macros = [('NO_ATLAS_INFO', 3)]
blas_opt_info:
    extra_link_args = ['-Wl,-framework', '-Wl,Accelerate']
    extra_compile_args = ['-msse3', '-I/System/Library/Frameworks/vecLib.framework/Headers']
    define_macros = [('NO_ATLAS_INFO', 3)]

Method 2

What you are searching for is this:
system info

I compiled numpy/scipy with atlas and i can check this with:

import numpy.distutils.system_info as sysinfo
sysinfo.get_info('atlas')

Check the documentation for more commands.

Method 3

You can use the link loader dependency tool to look at the C level hook components of your build and see whether they have external dependencies on your blas and lapack of choice. I am not near a linux box right now, but on an OS X machine you can do this inside the site-packages directory which holds the installations:

$ otool -L numpy/core/_dotblas.so 
numpy/core/_dotblas.so:
    /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.0)
    /System/Library/Frameworks/vecLib.framework/Versions/A/vecLib (compatibility version 1.0.0, current version 268.0.1)

$ otool -L scipy/linalg/flapack.so 
scipy/linalg/flapack.so (architecture i386):
    /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
    /usr/local/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 111.1.4)
    /System/Library/Frameworks/vecLib.framework/Versions/A/vecLib (compatibility version 1.0.0, current version 242.0.0)
scipy/linalg/flapack.so (architecture ppc):
    /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
    /usr/local/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 111.1.4)

$ otool -L scipy/linalg/fblas.so 
scipy/linalg/fblas.so (architecture i386):
    /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
    /usr/local/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 111.1.4)
    /System/Library/Frameworks/vecLib.framework/Versions/A/vecLib (compatibility version 1.0.0, current version 242.0.0)
scipy/linalg/fblas.so (architecture ppc):
    /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
    /usr/local/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 111.1.4)

substitute ldd in place of otool on a gnu/Linux system and you should get the answers you need.

Method 4

You can display BLAS, LAPACK, MKL linkage using show_config():

import numpy as np
np.show_config()

Which for me gives output:

mkl_info:
    libraries = ['mkl_rt', 'pthread']
    library_dirs = ['/my/environment/path/lib']
    define_macros = [('SCIPY_MKL_H', None), ('HAVE_CBLAS', None)]
    include_dirs = ['/my/environment/path/include']
blas_mkl_info:
    libraries = ['mkl_rt', 'pthread']
    library_dirs = ['/my/environment/path/lib']
    define_macros = [('SCIPY_MKL_H', None), ('HAVE_CBLAS', None)]
    include_dirs = ['/my/environment/path/include']
blas_opt_info:
    libraries = ['mkl_rt', 'pthread']
    library_dirs = ['/my/environment/path/lib']
    define_macros = [('SCIPY_MKL_H', None), ('HAVE_CBLAS', None)]
    include_dirs = ['/my/environment/path/include']
lapack_mkl_info:
    libraries = ['mkl_rt', 'pthread']
    library_dirs = ['/my/environment/path/lib']
    define_macros = [('SCIPY_MKL_H', None), ('HAVE_CBLAS', None)]
    include_dirs = ['/my/environment/path/include']
lapack_opt_info:
    libraries = ['mkl_rt', 'pthread']
    library_dirs = ['/my/environment/path/lib']
    define_macros = [('SCIPY_MKL_H', None), ('HAVE_CBLAS', None)]
    include_dirs = ['/my/environment/path/include']

Method 5

If you installed anaconda-navigator (at www.anaconda.com/anaconda/install/ for linux, Windows or macOS) – blas, scipy and numpy will all be installed and you can see them by clicking environments tab on left side of navigator home page (look for each directory in alpha order). Installing full anaconda (as opposed to miniconda or individual packages) will take care of installing many of the essential packages needed for data science.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0