BUG: Crash on import

[jan-david-fischbach]

This change in scipy leads to a crash at import time, when running a version of treams compiled with an incompatible version of scipy (before 1.14.1).

[jan-david-fischbach]

TypeError: C function scipy.special.cython_special.__pyx_fuse_0spherical_jn has wrong signature (expected __pyx_t_double_complex (long, __pyx_t_double_complex, int __pyx_skip_dispatch, struct __pyx_fuse_0__pyx_opt_args_5scipy_7special_14cython_special_spherical_jn *__pyx_optional_args), got __pyx_t_double_complex (Py_ssize_t, __pyx_t_double_complex, int __pyx_skip_dispatch, struct __pyx_fuse_0__pyx_opt_args_5scipy_7special_14cython_special_spherical_jn *__pyx_optional_args))

[jan-david-fischbach]

To summarize:

• scipy introduces a breaking change in v1.14.1 where the input parameters for many scipy.cython_special functions was changed from long to Py_ssize_t
• this makes the treams binaries compiled with a previous version of scipy incompatible to modern scipy and vice versa.
• these newest versions of scipy do only support python>=3.10
• As a consequence the only way forward, that I can see, is to drop support for python<=3.9 and require scipy>=1.14.1, against which we then compile. This breaks a lot of compatibility with older versions of these dependencies, but I do not see another way (as far as I can see we cannot adaptively install a different binary depending on the version of scipy).
• If a user wants to use treams with older versions of python/scipy they will have to resort to older versions of treams :/

[jan-david-fischbach]

Revised Summary

After the release of scipy v1.14.1 has lead to a binary incompatibility to the precompiled treams, I have now established the following solution (in #5):

1. For python<=3.9 we continue to compile treams as before, as scipy>=1.14.1 does not support these versions of python anyways.
2. For python>=3.10 we now compile against scipy>=1.14.1 and also require scipy>=1.14.1 for installation.

With this strategy we should cover all cases in which treams is newly installed.

Problems:

If a user has previously installed treams and now updates scipy [^1] it will result in the following error at import time:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/jd/bin/mambaforge/envs/treams-dev/lib/python3.10/site-packages/treams/__init__.py", line 63, in <module>
    from treams._core import (  # noqa: F401
  File "/home/jd/bin/mambaforge/envs/treams-dev/lib/python3.10/site-packages/treams/_core.py", line 8, in <module>
    import treams._operators as op
  File "/home/jd/bin/mambaforge/envs/treams-dev/lib/python3.10/site-packages/treams/_operators.py", line 8, in <module>
    import treams.special as sc
  File "/home/jd/bin/mambaforge/envs/treams-dev/lib/python3.10/site-packages/treams/special/__init__.py", line 204, in <module>
    from treams.special import _gufuncs, _ufuncs  # noqa: F401
  File "src/treams/special/_gufuncs.pyx", line 1, in init treams.special._gufuncs
    """Generalized universal functions for the special subpackage"""
  File "src/treams/special/_waves.pyx", line 1, in init treams.special._waves
    """Special mathematical functions related to waves"""
TypeError: C function scipy.special.cython_special.__pyx_fuse_0spherical_jn has wrong signature (expected __pyx_t_double_complex (long, __pyx_t_double_complex, int __pyx_skip_dispatch, struct __pyx_fuse_0__pyx_opt_args_5scipy_7special_14cython_special_spherical_jn *__pyx_optional_args), got __pyx_t_double_complex (Py_ssize_t, __pyx_t_double_complex, int __pyx_skip_dispatch, struct __pyx_fuse_0__pyx_opt_args_5scipy_7special_14cython_special_spherical_jn *__pyx_optional_args))

unfortunately I do not see any way around this.