DiffEqOperator Interface Compatibility

[ChrisRackauckas]

It'll be important to match the interface for it all to work in the stiff solvers "automatically". Here's a few points:

The problem is with update_coefficients!(A,t,u) which is different here.

https://github.com/JuliaDiffEq/DiffEqBase.jl/blob/master/src/diffeq_operator.jl#L6

The ODE solver needs to be able to call that an have the ODE update its coefficients. But also

https://github.com/JuliaDiffEq/PDEOperators.jl/blob/8ddcb5368824919ed46608f4ad2117b268e78b25/src/linear_operator.jl#L399

the call doesn't update the coefficients. I think that somehow there needs to be a system for if <: Number then BC is constant, otherwise assume the user gives a function a = bc(t) where a is the value for the constant you want.

[shivin9]

Yeah that was the system before, I was using anonymous functions with constant BC being represented as
t->constant. But then we decided that we should let the user update the values as he might do so in all sorts or different ways.

[ChrisRackauckas]

I think I made a big mistake when I suggested that be changed. That's my bad.