Support Python 3.12

[yguclu]

We make Psydac support Python 3.12 by using NumPy >= 2.0 together with Petsc4py >= 3.21 and the master branch of Igakit (updated on 6 Aug 2024). We also increase the required SymPDE version to 0.19.0. For simplicity, the same requirements are made for older versions of Python.

This closes #406.

Rationale

Python 3.12 does not have a distutils module. Therefore, NumPy 2.0 was released on 16 Jun 2024 with a new meson backend for the f2py tool which is part of the library. As of 6 Aug 2024, Igakit also moved from distutils to the meson-python build system in combination with NumPy 2.0.

The first version of petsc4py which is compatible with Python 3.12 is shipped with PETSc 3.21, hence we use this now instead of PETSc 3.20. Such a version of petsc4py also requires NumPy >= 2.0.

The move to NumPy 2.0 also means that some numeric datatypes behave differently. For this we need SymPDE >= 0.19.0.

Summary of changes

• In pyproject.toml, set maximum Python version to 3.12, and require SymPDE 0.19.0 instead of 0.18.3;
• In README.md, increase PETSc version to 3.21.4;
• In method integral of TensorFemSpace, convert any NumPy result to the native Python type to avoid errors with SymPy's sympify (after the upgrade to NumPy 2.0);
• Apply some bug fixes to the unit tests after the upgrade of NumPy and SymPDE;
• In continuous-integration.yml, add tests with Python 3.12, increase PETSc version to 3.21.4, and add check of parallel h5py.

[kvrigor]

Summary of what I understood in this PR:

• Python3.12 support enabled in continuous-integration.yml and new sympde 0.19.0 reflected in pyproject.toml
• Diffs in tests are due to bugfixes by @campospinto and @yguclu
• Running maxwell_2d_multi_patch.py gives a passing result:

$ python3.12 examples/maxwell_2d_multi_patch.py
> Grid          :: [4,4]
> Degree        :: [2,2]
> CG info       ::  {'niter': 829, 'success': np.True_, 'res_norm': 9.976906608695098e-09}
> L2 error      :: 1.59e+00

> Solution time :: 2.72e+01
> Evaluat. time :: 3.61e-02