f2py

Fortran to Python interface generator

TLDR

Generate Python wrapper for Fortran

$ f2py -c [module.f90] -m [module_name]

Create signature file

$ f2py [module.f90] -h [module.pyf]

Build with specific compiler

$ f2py -c --fcompiler=[gfortran] [module.f90] -m [module_name]

Link external libraries

$ f2py -c [module.f90] -m [module_name] -l[blas]

Show available compilers

$ f2py --help-fcompiler

SYNOPSIS

f2py [options] fortran-files [options]

f2py (Fortran to Python) is a NumPy tool that creates Python bindings for Fortran code. It generates wrapper modules that allow calling Fortran subroutines and functions directly from Python.
The tool automatically handles type conversion between Python/NumPy arrays and Fortran arrays. It parses Fortran source code or signature files to determine interfaces, then generates C wrapper code compiled into a Python extension module.
f2py enables using high-performance Fortran libraries in Python scientific computing workflows without rewriting existing code.

PARAMETERS

FORTRAN-FILES

Fortran source files (.f, .f90, .f95).

-c

Compile and build extension module.

-m NAME

Set module name.

-h FILE

Generate signature file.

--fcompiler NAME

Specify Fortran compiler.

-l LIBRARY

Link with library.

-L PATH

Library search path.

-I PATH

Include search path.

--help-fcompiler

List available Fortran compilers.

--help

Display help information.

CAVEATS

Requires Fortran compiler and NumPy installation. Complex Fortran constructs may need signature file tweaks. Array ordering differs between Fortran (column-major) and C (row-major).

HISTORY

f2py was created by Pearu Peterson in the late 1990s and became part of NumPy. It bridges Python's scientific computing ecosystem with decades of Fortran numerical libraries, enabling their continued use in modern Python workflows.