The source member,
~/opt/anaconda3/lib/python3.11/site-packages/numpy/f2py/_backends/-init_.py,
def f2py_build_generator(name):
if name == "meson":
from ._meson import MesonBackend
return MesonBackend
elif name == "distutils":
from ._distutils import DistutilsBackend
return DistutilsBackend
else:
raise ValueError(f"Unknown backend: {name}")
appears to be where the "key" is chosen, furthermore, in f2p2e.py sets the
background_key and invokes 2py_build_generator. To my knowledge, I'm not
running meson. So, what do you think the best way is to fix my problem?
Please advise,
Sam Dupree
On Sun, 04 Jan 2026 18:23:22 -0800, Bill Ross <[email protected]> wrote:
Uninformed debugging:
> build_backend = f2py_build_generator(backend_key)
Can you inspect that backend_key? It seems like it could be 'key' to choosing
the wrong back end.
Bill
--
Phobrain.com
On 2026-01-04 17:18, Samuel H Dupree Jr wrote:
I am resurrecting a Python program I wrote a few years under Python 3.9. I'm
presently:
Running Python 3.11 under Mac OSX Sequoia (ver. 15.7.1)
Using NumPy version 1.26.4
Running on an Intel (x86-64) Mac Pro Desktop (2019)
The program uses a Fortran 77 subroutine that was wrapped using f2py when I
running Python 3.9. However, when I attempt to wrap that same subroutine (the
source code is attached to this note) using f2py in Python 3.11, I get the
following error message.
(base) user@Mac-Pro accgravityfiled_builder_f2py % f2py -c accgravityfield.f
-m accgravityfield
Traceback (most recent call last):
File "/Users/user/opt/anaconda3/bin/f2py", line 8, in <module>
sys.exit(main())
^^^^^^
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/f2py/f2py2e.py",
line 766, in main
run_compile()
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/f2py/f2py2e.py",
line 594, in run_compile
build_backend = f2py_build_generator(backend_key)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/f2py/_backends/__init__.py",
line 6, in f2py_build_generator
from ._distutils import DistutilsBackend
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/f2py/_backends/_distutils.py",
line 3, in <module>
from numpy.distutils.core import setup, Extension
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/distutils/core.py",
line 24, in <module>
from numpy.distutils.command import config, config_compiler, \
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/distutils/command/config.py",
line 19, in <module>
from numpy.distutils.mingw32ccompiler import generate_manifest
File
"/Users/user/opt/anaconda3/lib/python3.11/site-packages/numpy/distutils/mingw32ccompiler.py",
line 27, in <module>
from distutils.msvccompiler import get_build_version as
get_build_msvc_version
ModuleNotFoundError: No module named 'distutils.msvccompiler'
(base) user@Mac-Pro accgravityfiled_builder_f2py %
As for gfortran is concerned:
(base) user@Mac-Pro accgravityfiled_builder_f2py % gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/usr/local/Cellar/gcc/15.2.0/bin/../libexec/gcc/x86_64-apple-darwin24/15/lto-wrapper
Target: x86_64-apple-darwin24
Configured with: ../configure --prefix=/usr/local/opt/gcc
--libdir=/usr/local/opt/gcc/lib/gcc/current --disable-nls
--enable-checking=release --with-gcc-major-version-only
--enable-languages=c,c++,objc,obj-c++,fortran --program-suffix=-15
--with-gmp=/usr/local/opt/gmp --with-mpfr=/usr/local/opt/mpfr
--with-mpc=/usr/local/opt/libmpc --with-isl=/usr/local/opt/isl
--with-zstd=/usr/local/opt/zstd --with-pkgversion='Homebrew GCC 15.2.0'
--with-bugurl=https://github.com/Homebrew/homebrew-core/issues
--with-system-zlib --build=x86_64-apple-darwin24
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 15.2.0 (Homebrew GCC 15.2.0)
(base) user@Mac-Pro accgravityfiled_builder_f2py %
I have two questions:
Why is f2py in a Mac OSX Intel based environment attempting to import
'distutils.msvccompiler' that is required for Windows' environment only?
What do I need to do to eliminate this problem?
Any thoughts?
Sam Dupree
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