Why does SPaRK not inherit from diffrax.AbstractAdaptiveSolver?

[lockwo]

>>> isinstance(diffrax.ImplicitEuler(), diffrax.AbstractAdaptiveSolver)
True
>>> isinstance(diffrax.SlowRK(), diffrax.AbstractAdaptiveSolver)
False
>>> isinstance(diffrax.SPaRK(), diffrax.AbstractAdaptiveSolver)
False

(I accidentally closed #669 and couldn't reopen it 😅 )

[patrick-kidger]

I think that's just an oversight. Looks like none of our AbstractSRK are marked as adaptive, as indeed they can be non-adaptive tableau.b_error = None. Looks like those SRKs which have tableau.b_error != None should additionally inherit from AbstractAdaptiveSolver.

Happy to take a PR on this!

[patrick-kidger]

Fixed in #674.