Flattened arrays at the output of a DifferentialEquations solver

[JordiBolibar]

I’m solving a PDE on a Matrix directly with ComponentArray, but I’m getting flattened solutions at the output (1-dimensional).

p = (Γ, Δx, Δy, η)
u₀ = ComponentArray(H=H₀, B=B) # H and B are Matrices with size (193, 189)
tspan = (0.0, 10.0)
# Create ODE problem based on the SIA
SIA_prob = ODEProblem(iceflow!, u₀, tspan, p)
# Solve the SIA 
SIA_sol = solve(SIA_prob, Tsit5())

And when I do:
println(size(SIA_sol.u[end]))
Instead of getting (193, 189), I get:
(72954,)
Which corresponds to the two matrices contained in u (H and B), flattened and concatenated.

Is this an expected behaviour? Shouldn't the same dimensions from the input be preserved?

[jonniedie]

Yeah, that's expected and necessary for it to work as something "vector-like" for the solver. Also, since ComponentArrays can be arbitrarily nested, a size that returned the size of the inner components wouldn't always make sense.

If you want the size of an internal component, say H, do size(u.H).

[JordiBolibar]

That worked. Thanks a lot @jonniedie!

[jonniedie]

No prob!