OpenVSP Python API Compiled with Wrong NumPY Version

[Striker2783]

Error Log

A module that was compiled using NumPy 1.x cannot be run in
NumPy 2.4.2 as it may crash. To support both 1.x and 2.x
versions of NumPy, modules must be compiled with NumPy 2.0.
Some module may need to rebuild instead e.g. with 'pybind11>=2.12'.

If you are a user of the module, the easiest solution will be to
downgrade to 'numpy<2' or try to upgrade the affected module.
We expect that some modules will need time to support NumPy 2.

This is because Ubuntu's python3-numpy package is outdated to 1.26.4 and the environment.yml file uses the latest version of NumPY 2.4.2. Either set the environment.yml NumPY version to 1.26.4 or find a way to use an updated version of NumPY.

[ramcdona]

@M4Nascenzi

Did you see this error at compile time, or when loading the openvsp module, or something else?

Which version of Ubuntu are you working with?

[Striker2783]

This happens when I try to load the OpenVSP module in Python. On Ubuntu 24.04. I followed the instructions on the README.md to install it.

import openvsp

Stacktrace

    import openvsp
  File "/home/user/miniconda3/envs/vsppytools/lib/python3.12/site-packages/openvsp/__init__.py", line 45, in <module>
    from .vsp import *
  File "/home/user/miniconda3/envs/vsppytools/lib/python3.12/site-packages/openvsp/vsp.py", line 10, in <module>
    from . import _vsp
Traceback (most recent call last):
  File "/home/user/miniconda3/envs/vsppytools/lib/python3.12/site-packages/numpy/core/_multiarray_umath.py", line 46, in __getattr__
    raise ImportError(msg)

[M4Nascenzi]

It seems like the downloaded windows version is compiled with a 2.x version of numpy and works with my numpy 2.x version.

Based on your error, it looks like the python you are importing openvsp with has numpy 2.x installed, which can't interface with an openvsp built with a numpy 1.x.

If you downloaded it off the internet, we need to fix the automated ubuntu build to build with numpy 2.x.

If you built it yourself, you should build it with a newer version of numpy (ideally using the one in the python environment you are using to run "import openvsp"). I believe we set it up so that cmake will tell you which python and which numpy was found. If cmake is finding the wrong versions, there's probably some cmake variables you can set to make it point to the right version.

[ramcdona]

I believe he is using the package downloaded from the internet -- so it is our problem.

This is the first version where the build had depended on numpy. When I rolled this release, I did not get numpy added to the GitHub Actions build system. Striker2783 helped get this sorted...

6697aab

So, this is achieved via:

sudo apt-get install python3-numpy

Which appears to install an old version.

So we either need to figure out how to use apt-get to install a newer version -- or we need to use some other approach (perhaps pip or conda or whatever) to install a newer version.

An alternate approach would be to reduce the numpy requirement in the environment.yml file -- do we know why we require 2.4?

Perhaps related, on my machine, this stuff complains about using a deprecated API:

In file included from /Users/ramcdona/Documents/OpenVSP/build/llvmrwdi-VSP-noasan/src/python_api/CMakeFiles/pyvsp_g.dir/vsp_g_pythonPYTHON_wrap.cxx:3642:
In file included from /opt/homebrew/anaconda3/python.app/Contents/lib/python3.12/site-packages/numpy/_core/include/numpy/arrayobject.h:5:
In file included from /opt/homebrew/anaconda3/python.app/Contents/lib/python3.12/site-packages/numpy/_core/include/numpy/ndarrayobject.h:12:
In file included from /opt/homebrew/anaconda3/python.app/Contents/lib/python3.12/site-packages/numpy/_core/include/numpy/ndarraytypes.h:1909:
/opt/homebrew/anaconda3/python.app/Contents/lib/python3.12/site-packages/numpy/_core/include/numpy/npy_1_7_deprecated_api.h:17:2: warning: "Using deprecated NumPy API, disable it with "          "#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION" [-W#warnings]
   17 | #warning "Using deprecated NumPy API, disable it with " \
      |  ^
/Users/ramcdona/Documents/OpenVSP/build/llvmrwdi-VSP-noasan/src/python_api/CMakeFiles/pyvsp_g.dir/vsp_g_pythonPYTHON_wrap.cxx:81828:3: warning: implicit conversion of NULL constant to 'int' [-Wnull-conversion]
 81828 |   import_array();
       |   ^~~~~~~~~~~~~~
/opt/homebrew/anaconda3/python.app/Contents/lib/python3.12/site-packages/numpy/_core/include/numpy/__multiarray_api.h:1588:12: note: expanded from macro 'import_array'
 1588 |     return NULL; \
      |     ~~~~~~ ^
2 warnings generated.

[M4Nascenzi]

The environment.yml file does not require 2.4. I believe pip is just installing the newest version that is compatible. We would have to have openvsp require an older version of numpy, which would probably start breaking a lot of peoples workflows (e.g. the latest version of OpenMDAO requires numpy > 2.0, and I'm sure a lot of other packages too). Furthermore, that error says that numpy 1.X will work with an OpenVSP compiled with 2.X.

[ramcdona]

OK, then the solution is to install a modern numpy during the GitHub actions build.

This is most likely achievable by removing python3-numpy from the apt-get install and instead installing pip. Then, use pip to install numpy (possibly forcing a version).

However, I'm not sure if that will install the modern numpy into the global environment, or if we need to somehow set up a virtual environment in the GitHub actions instance...

[ramcdona]

Fix included with 3.48.0. Thanks for the help on this!

[pjdewitte]

I still encounter the same error with OpenVSP 3.48.2 on Ubuntu 24.04:

$ wget -O /tmp/OpenVSP.deb "https://openvsp.org/download.php?file=zips/current/linux/OpenVSP-3.48.2-Ubuntu-24.04_amd64.deb"
2026-03-10 19:31:58 URL:https://openvsp.org/zips/current/linux/OpenVSP-3.48.2-Ubuntu-24.04_amd64.deb [137855796/137855796] -> "/tmp/OpenVSP.deb" [1]

$ sudo apt-get install -y /tmp/OpenVSP.deb
...

$ cd /opt/OpenVSP/python/openvsp/openvsp

/opt/OpenVSP/python/openvsp/openvsp$ sudo apt-get install python3-venv

/opt/OpenVSP/python/openvsp/openvsp$ python3 -m venv /tmp/.venv

/opt/OpenVSP/python/openvsp/openvsp$ source /tmp/.venv/bin/activate

(.venv) /opt/OpenVSP/python/openvsp/openvsp$ pip install numpy
Collecting numpy
  Downloading numpy-2.4.3-cp312-cp312-manylinux_2_27_x86_64.manylinux_2_28_x86_64.whl.metadata (6.6 kB)
Downloading numpy-2.4.3-cp312-cp312-manylinux_2_27_x86_64.manylinux_2_28_x86_64.whl (16.6 MB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 16.6/16.6 MB 10.8 MB/s eta 0:00:00
Installing collected packages: numpy
Successfully installed numpy-2.4.3

(.venv) /opt/OpenVSP/python/openvsp/openvsp$ python
Python 3.12.3 (main, Mar  3 2026, 12:15:18) [GCC 13.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import vsp

A module that was compiled using NumPy 1.x cannot be run in
NumPy 2.4.3 as it may crash. To support both 1.x and 2.x
versions of NumPy, modules must be compiled with NumPy 2.0.
Some module may need to rebuild instead e.g. with 'pybind11>=2.12'.

If you are a user of the module, the easiest solution will be to
downgrade to 'numpy<2' or try to upgrade the affected module.
We expect that some modules will need time to support NumPy 2.

Traceback (most recent call last):  File "<stdin>", line 1, in <module>
  File "/opt/OpenVSP/python/openvsp/openvsp/vsp.py", line 12, in <module>
    import _vsp
Traceback (most recent call last):
  File "/tmp/.venv/lib/python3.12/site-packages/numpy/core/_multiarray_umath.py", line 46, in __getattr__
    raise ImportError(msg)

>>> import numpy
>>> numpy.version.full_version
'2.4.3'

I don't have numpy installed system-wide. Somehow OpenVSP still picks up numpy 1.x.

Let me know if I can do additional testing!

[ramcdona]

It looks like I missed a patch from @Striker2783 when I pushed out 3.48 -- I'll grab it in the next version.