fix: recursively unwrap arrays of symbolics in process_SciMLProblem

Author: AayushSabharwal

src/systems/problem_utils.jl

@@ -171,7 +171,24 @@ function to_varmap(vals, varlist::Vector)
         check_eqs_u0(varlist, varlist, vals)
         vals = vec(varlist) .=> vec(vals)
     end
-    return anydict(unwrap(k) => unwrap(v) for (k, v) in anydict(vals))
+    return recursive_unwrap(anydict(vals))
+end
+
+"""
+    $(TYPEDSIGNATURES)
+
+Recursively call `Symbolics.unwrap` on `x`. Useful when `x` is an array of (potentially)
+symbolic values, all of which need to be unwrapped. Specializes when `x isa AbstractDict`
+to unwrap keys and values, returning an `AnyDict`.
+"""
+function recursive_unwrap(x::AbstractArray)
+    symbolic_type(x) == ArraySymbolic() ? unwrap(x) : recursive_unwrap.(x)
+end
+
+recursive_unwrap(x) = unwrap(x)
+
+function recursive_unwrap(x::AbstractDict)
+    return anydict(unwrap(k) => recursive_unwrap(v) for (k, v) in x)
 end
 
 """
@@ -410,7 +427,7 @@ function process_SciMLProblem(
     u0map = to_varmap(u0map, dvs)
     _pmap = pmap
     pmap = to_varmap(pmap, ps)
-    defs = add_toterms(defaults(sys))
+    defs = add_toterms(recursive_unwrap(defaults(sys)))
     cmap, cs = get_cmap(sys)
     kwargs = NamedTuple(kwargs)
 

test/initial_values.jl

@@ -119,3 +119,12 @@ end
 prob = ODEProblem(sys, [], (1.0, 2.0), [])
 @test prob[x] == 1.0
 @test prob.ps[p] == 2.0
+
+@testset "Array of symbolics is unwrapped" begin
+    @variables x(t)[1:2] y(t)
+    @mtkbuild sys = ODESystem([D(x) ~ x, D(y) ~ t], t; defaults = [x => [y, 3.0]])
+    prob = ODEProblem(sys, [y => 1.0], (0.0, 1.0))
+    @test eltype(prob.u0) <: Float64
+    prob = ODEProblem(sys, [x => [y, 4.0], y => 2.0], (0.0, 1.0))
+    @test eltype(prob.u0) <: Float64
+end