Sundials CVODE_BDF does not support ComponentArrays #332
Description
Description
The Sundials CVODE_BDF solver does not support ComponentVector inputs directly. When trying to solve an ODE with a ComponentVector initial condition using CVODE_BDF, it fails with:
MethodError: no method matching Sundials.NVector(::ComponentVector{Float64, ...}, ::Ptr{Nothing})
The NVector constructor in Sundials only accepts Vector{Float64}, not ComponentVector.
Reproduction
using ComponentArrays, DifferentialEquations, Sundials
x0 = ComponentArray(x = ones(10))
prob = ODEProblem((u, p, t) -> u, x0, (0.0, 1.0))
sol = solve(prob, CVODE_BDF(linear_solver = :BCG), reltol = 1.0e-15, abstol = 1.0e-15)
# MethodError: no method matching Sundials.NVector(::ComponentVector{...}, ::Ptr{Nothing})Current Status
The test in test/downstream/diffeq_tests.jl (Issue 53 test) has been marked as @test_broken in #332.
This likely needs a fix in either Sundials.jl (to accept AbstractVector in NVector) or in ComponentArrays (to provide a conversion method).
Context
Originally from #53. This test was previously in a dead test directory (test/diffeq_test/) that was not wired up to CI. Now that downstream tests are running in CI, this incompatibility is visible.