.. _f2py-win-intel:

============================== F2PY and Windows Intel Fortran

As of NumPy 1.23, only the classic Intel compilers (ifort) are supported.

.. note::

The licensing restrictions for beta software `have been relaxed`_ during
the transition to the LLVM backed ``ifx/icc`` family of compilers.
However this document does not endorse the usage of Intel in downstream
projects due to the issues pertaining to `disassembly of components and
liability`_.

Neither the Python Intel installation nor the `Classic Intel C/C++
Compiler` are required.

The Intel Fortran Compilers_ come in a combined installer providing both Classic and Beta versions; these also take around a gigabyte and a half or so.

We will consider the classic example of the generation of Fibonnaci numbers, fib1.f, given by:

.. literalinclude:: ../code/fib1.f :language: fortran

For cmd.exe fans, using the Intel oneAPI command prompt is the easiest approach, as it loads the required environment for both ifort and msvc. Helper batch scripts are also provided.

.. code-block:: bat

cmd.exe

"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" python -m numpy.f2py -c fib1.f -m fib1 python -c "import fib1; import numpy as np; a=np.zeros(8); fib1.fib(a); print(a)"

Powershell usage is a little less pleasant, and this configuration now works with MSVC as:

.. code-block:: powershell

Powershell

python -m numpy.f2py -c fib1.f -m fib1 --f77exec='C:\Program Files (x86)\Intel\oneAPI\compiler\latest\windows\bin\intel64\ifort.exe' --f90exec='C:\Program Files (x86)\Intel\oneAPI\compiler\latest\windows\bin\intel64\ifort.exe' -L'C:\Program Files (x86)\Intel\oneAPI\compiler\latest\windows\compiler\lib\ia32' python -c "import fib1; import numpy as np; a=np.zeros(8); fib1.fib(a); print(a)"

Alternatively, set environment and reload Powershell in one line

cmd.exe /k '"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" && powershell' python -m numpy.f2py -c fib1.f -m fib1 python -c "import fib1; import numpy as np; a=np.zeros(8); fib1.fib(a); print(a)"

Note that the actual path to your local installation of ifort may vary, and the command above will need to be updated accordingly.

.. _have been relaxed: https://www.intel.com/content/www/us/en/developer/articles/release-notes/oneapi-fortran-compiler-release-notes.html .. _disassembly of components and liability: https://www.intel.com/content/www/us/en/developer/articles/license/end-user-license-agreement.html .. _Intel Fortran Compilers: https://www.intel.com/content/www/us/en/developer/articles/tool/oneapi-standalone-components.html#inpage-nav-6-1 .. _Classic Intel C/C++ Compiler: https://www.intel.com/content/www/us/en/developer/articles/tool/oneapi-standalone-components.html#inpage-nav-6-undefined