PR Summary

Deprecating two functions that should be internal. Original issue (as discussed on gitter):

Digging into ticker.py and found the following concern: is_close_to_int uses a keyword argument atol (absolute tolerance?) comparing using absolute tolerance. However, it is also called from isdecade where the keyword argument rtol (relative tolerance?) is passed as absolut tolerance.

1. It seems like relative tolerance makes more sense for is_close_to_int
2. It seems inconsistent to pass rtol as atol (if now the keyword naming actually says something)

If I would change this, I guess the safest way is to provide an additional keyword argument to is_close_to_int, rtol=None, check if that is set and if so use that instead? For isdecade it is not so obvious as making it consistent will break the behavior.

(I originally just wanted to use isdecade in a few places...)

Outcome:

• Deprecating is_decade and introducing _is_decade that use rtol as relative tolerance, not as absolute tolerance.
• Deprecating is_close_to_int which is not replaced (rely on math.isclose and np.isclose).

The behavior is slightly changed, although it is hard to say that if it will actually be an issue. The tolerances seems quite arbitrarily set and considering that these are mainly used for exponents of bases, so typically rather small integers. But there may indeed be cases which will behave differently now.

PR Checklist

Tests and Styling

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (install flake8-docstrings and run flake8 --docstring-convention=all).

Documentation

• [N/A] New features are documented, with examples if plot related.
• [N/A] New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).
• [N/A] Documentation is sphinx and numpydoc compliant (the docs should build without error).