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Selecting Backend Library

  • Numo::Linalg accesses BLAS/LAPACK library throuh dynamic linking loader at runtime. This design allows you to change backend libraries without re-compiling Numo::Linalg.

  • Note that the performance depends on the backend libraries as shown in benchmark.

Install time option to specify default library path

gem install numo-linalg -- \
  --with-backend=mkl \
  --with-mkl-lib=/opt/intel/mkl/lib/intel64 \
  --with-openblas-dir=/opt/OpenBLAS \
  --with-atlas-dir=/opt/ATLAS \
  --with-lapack-lib=/opt/LAPACK/lib64
  • Note that these options are for setting default path to load library at runtime, not required for building Numo::Linalg library.

Use Numo::Linalg

Use default backend

require "numo/linalg"
  • if --with-backend option is specified, use it.
  • if --with-backend option is not specified, try to load mkl,openblas,atlas,lapack.

Specify backend

  • 1st level (specify backend library)
require "numo/linalg/use/openblas"

or

require "numo/linalg/use/atlas"

or

require "numo/linalg/use/mkl"

or

require "numo/linalg/use/lapack"
  • 2nd level (specify library path)
require "numo/linalg/linalg"
Numo::Linalg::Loader.load_openblas "/opt/OpenBLAS/lib"
  • 3rd level (specify library files to load)
require "numo/linalg/linalg"
Numo::Linalg::Blas.dlopen("/opt/OpenBLAS/lib/libopenblas.so")
Numo::Linalg::Lapack.dlopen("/opt/OpenBLAS/lib/libopenblas.so")
  • Numo::Linalg requires C-interface CBLAS and LAPACKE interface. If they are provided as separate libraries, you need to open all of them.
require "numo/linalg/linalg"
require "fiddle"
Fiddle.dlopen("libblas.so")  # referenced from CBLAS
Fiddle.dlopen("liblapack.so")  # referenced from LAPACKE
Numo::Linalg::Blas.dlopen("libcblas.so")  # contains cblas_* function
Numo::Linalg::Lapack.dlopen("liblapacke.so")  # containes LAPACKE_* function
  • Reopen (change backend at runtime) is not supported.

Show libraries

p Numo::Linalg::Loader.libs