expectation() should use p and u0 from ODEProblem

[owiecc]

What is the rationale behind having to explicitly pass the initial conditions and parameters to expectation function if these can be embedded into the ODEProblem?

function expectation(g::Function, prob::ODEProblem, u0, p, expalg::Koopman, args...)

This makes the code a bit strange as I can have double definitions of initial conditions and one seems to be ignored.

f(u,p,t) = p.*u

u0 = [-666.666]
u0_dist = [truncated(Normal(3.0,2.0),3-1000,3+1000)]

p = [-0.3]
tspan = (0.0,10.0)
prob = ODEProblem(f,u0,tspan,p)

expectation(f -> f(1.0), prob, u0_dist, p, Koopman(), Tsit5())

Wouldn't this be enough or am I missing something?

prob = ODEProblem(f,u0_dist,tspan,p)
expectation(f -> f(1.0), prob, Koopman(), Tsit5())

[ChrisRackauckas]

It's just a quirk of history. This project started before you could define and use initial conditions as distributions, so its interface needed to accommodate for that. Now the interface is super flexible, so it just works. We should update this package to use the interface you describe.