Prioritize filtered_u0 deferral when creating initialization system

Author: hersle

src/systems/nonlinear/initializesystem.jl

@@ -44,7 +44,10 @@ function generate_initializesystem(sys::ODESystem;
                 y = get(schedule.dummy_sub, x[1], x[1])
                 y = ModelingToolkit.fixpoint_sub(y, full_diffmap)
 
-                if y isa Symbolics.Arr
+                if y ∈ set_full_states
+                    # defer initialization until defaults are merged below
+                    push!(filtered_u0, y => x[2])
+                elseif y isa Symbolics.Arr
                     _y = collect(y)
 
                     # TODO: Don't scalarize arrays
@@ -55,8 +58,6 @@ function generate_initializesystem(sys::ODESystem;
                     # y is a derivative expression expanded
                     # add to the initialization equations
                     push!(eqs_ics, y ~ x[2])
-                elseif y ∈ set_full_states
-                    push!(filtered_u0, y => x[2])
                 else
                     error("Initialization expression $y is currently not supported. If its a higher order derivative expression, then only the dummy derivative expressions are supported.")
                 end