F2PY and Windows Intel Fortran

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

• 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:

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.

# 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:

# 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.