F2PY user guide and reference manual

The purpose of the F2PY –Fortran to Python interface generator– utility is to provide a connection between Python and Fortran. F2PY distributed as part of NumPy (numpy.f2py) and once installed is also available as a standalone command line tool. Originally created by Pearu Peterson, and older changelogs are in the historical reference.

F2PY facilitates creating/building native Python C/API extension modules that make it possible

• to call Fortran 77/90/95 external subroutines and Fortran 90/95 module subroutines as well as C functions;

• to access Fortran 77 COMMON blocks and Fortran 90/95 module data, including allocatable arrays

from Python.

Note

Fortran 77 is essentially feature complete, and an increasing amount of Modern Fortran is supported within F2PY. Most iso_c_binding interfaces can be compiled to native extension modules automatically with f2py. Bug reports welcome!

F2PY can be used either as a command line tool f2py or as a Python module numpy.f2py. While we try to provide the command line tool as part of the numpy setup, some platforms like Windows make it difficult to reliably put the executables on the PATH. If the f2py command is not available in your system, you may have to run it as a module:

python -m numpy.f2py

Using the python -m invocation is also good practice if you have multiple Python installs with NumPy in your system (outside of virtual environments) and you want to ensure you pick up a particular version of Python/F2PY.

If you run f2py with no arguments, and the line numpy Version at the end matches the NumPy version printed from python -m numpy.f2py, then you can use the shorter version. If not, or if you cannot run f2py, you should replace all calls to f2py mentioned in this guide with the longer version.

• F2PY user guide
  • Three ways to wrap - getting started
    • The quick way
    • The smart way
    • The quick and smart way
  • Using F2PY
    • Using f2py as a command-line tool
    • Python module numpy.f2py
    • Automatic extension module generation
  • F2PY examples
    • F2PY walkthrough: a basic extension module
    • A filtering example
    • depends keyword example
    • Read more
• F2PY reference manual
  • Signature file
    • Signature files syntax
  • Using F2PY bindings in Python
    • Fortran type objects
    • Scalar arguments
    • String arguments
    • Array arguments
    • Call-back arguments
    • Common blocks
    • Fortran 90 module data
    • Allocatable arrays
  • F2PY and build systems
    • Basic concepts
    • Build systems
  • Advanced F2PY use cases
    • Adding user-defined functions to F2PY generated modules
    • Adding user-defined variables
    • Dealing with KIND specifiers
    • Character strings
  • Boilerplate reduction and templating
    • Using FYPP for binding generic interfaces
  • F2PY test suite
    • Adding a test
• F2PY and Windows
  • Overview
  • Baseline
  • PowerShell and MSVC
  • Microsoft Store Python paths
    • F2PY and Windows Intel Fortran
    • F2PY and Windows with MSYS2
    • F2PY and Conda on Windows
    • F2PY and PGI Fortran on Windows
• 1 Migrating to meson
  • 1.1 Baseline
  • 1.2 Compilation options
    • 1.2.1 Basic Usage
    • 1.2.2 Specify the backend
    • 1.2.3 Pass a compiler name
    • 1.2.4 Dependencies
    • 1.2.5 Libraries
  • 1.3 Customizing builds