Merge pull request #1567 from SciML/myb/union_array

Support array of arrays in `varmap_to_vars `

Author: YingboMa

src/utils.jl

@@ -481,20 +481,31 @@ function promote_to_concrete(vs; tofloat=true, use_union=false)
         vs
     else
         C = typeof(first(vs))
-        has_int = false
         I = Int8
+        has_int = false
+        has_array = false
+        array_T = nothing
         for v in vs
+            if v isa AbstractArray
+                has_array = true
+                array_T = typeof(v)
+            end
             E = eltype(v)
             C = promote_type(C, E)
             if E <: Integer
                 has_int = true
                 I = promote_type(I, E)
             end
         end
-        if tofloat
+        if tofloat && !has_array
             C = float(C)
-        elseif use_union && has_int && C !== I
-            C = Union{C, I}
+        elseif has_array || (use_union && has_int && C !== I)
+            if has_array
+                C = Union{C, array_T}
+            end
+            if has_int
+                C = Union{C, I}
+            end
             return copyto!(similar(vs, C), vs)
         end
         convert.(C, vs)

test/odesystem.jl

@@ -746,3 +746,12 @@ let
     @named sys = ODESystem(eqs, t, vars, pars)
     @test_throws ModelingToolkit.ExtraEquationsSystemException structural_simplify(sys)
 end
+
+# 1561
+let
+    vars = @variables x y
+    arr = ModelingToolkit.varmap_to_vars([x => 0.0, y => [0.0, 1.0]], vars) #error
+    sol = Union{Float64, Vector{Float64}}[0.0, [0.0, 1.0]]
+    @test arr == sol
+    @test typeof(arr) == typeof(sol)
+end