Uninitialized field `opnorm` in JacVecOperator

[danielwe]

opnorm is left uninitialized here:

DiffEqOperators.jl/src/jacvec_operators.jl

Lines 24 to 33 in 4b1bd63

	new{T,typeof(f),Nothing,Nothing,Any,P,tType,typeof(opnorm)}(
	f,
	nothing,
	nothing,
	nothing,
	nothing,
	nothing,
	autodiff,
	ishermitian,
	)

Another instance of JuliaLang/julia#24943

[danielwe]

Same issue in vecjac_operators.jl:

DiffEqOperators.jl/src/vecjac_operators.jl

Lines 23 to 32 in 4b1bd63

	new{T,typeof(f),Nothing,Nothing,Any,P,tType,typeof(opnorm)}(
	f,
	nothing,
	nothing,
	nothing,
	nothing,
	nothing,
	autodiff,
	ishermitian,
	)

[ChrisRackauckas]

These should probably just be deprecated and deleted in favor of the ones that are more updated in SparseDiffTools.

[xtalax]

Are we sure that they are completely obselete? I'd prefer to leave the operators up for now until we have stencil interfaces in MOL for the high point count problems and warn of future deprecation, with links to successor packages.
Do MethodOfLines and SparseDiffTools cover all use cases?

[ChrisRackauckas]

Yes, these ones are not robust to alternative tags like SparseDiffTools is, so pretty much any use case should use that. There's a few things in here that aren't in there to match the AbstractSciMLOperator interface, but what we probably need to do is just make that interface package a lean package and then let SparseDiffTools extend that, add the one function, and then there's no reason for the operators here.