Merge pull request #2978 from SebastianM-C/smc/quick_fix

Fix parameter dependencies across model hierarchy

Author: ChrisRackauckas

src/systems/abstractsystem.jl

@@ -1240,7 +1240,7 @@ function namespace_equation(eq::Equation,
         ivs = independent_variables(sys))
     _lhs = namespace_expr(eq.lhs, sys, n; ivs)
     _rhs = namespace_expr(eq.rhs, sys, n; ivs)
-    _lhs ~ _rhs
+    (_lhs ~ _rhs)::Equation
 end
 
 function namespace_assignment(eq::Assignment, sys)
@@ -1346,16 +1346,11 @@ function parameter_dependencies(sys::AbstractSystem)
     pdeps = get_parameter_dependencies(sys)
     systems = get_systems(sys)
     # put pdeps after those of subsystems to maintain topological sorted order
-    if isempty(systems)
-        return pdeps
-    else
-        return vcat(
-            reduce(vcat,
-                [map(eq -> namespace_equation(eq, s), parameter_dependencies(s))
-                 for s in systems]),
-            pdeps
-        )
-    end
+    namespaced_deps = mapreduce(
+        s -> map(eq -> namespace_equation(eq, s), parameter_dependencies(s)), vcat,
+        systems; init = Equation[])
+
+    return vcat(namespaced_deps, pdeps)
 end
 
 function full_parameters(sys::AbstractSystem)

test/parameter_dependencies.jl

@@ -153,6 +153,30 @@ end
     @test new_prob.ps[sys2.p2] == 3.0
 end
 
+@testset "parameter dependencies across model hierarchy" begin
+    sys2 = let name = :sys2
+        @parameters p2
+        @variables x(t) = 1.0
+        eqs = [D(x) ~ p2]
+        ODESystem(eqs, t, [x], [p2]; name)
+    end
+
+    @parameters p1 = 1.0
+    parameter_dependencies = [sys2.p2 ~ p1 * 2.0]
+    sys1 = ODESystem(
+        Equation[], t, [], [p1]; parameter_dependencies, name = :sys1, systems = [sys2])
+
+    # ensure that parameter_dependencies is type stable
+    # (https://github.com/SciML/ModelingToolkit.jl/pull/2978)
+    @inferred ModelingToolkit.parameter_dependencies(sys1)
+
+    sys = structural_simplify(sys1)
+
+    prob = ODEProblem(sys, [], (0.0, 1.0))
+    sol = solve(prob)
+    @test SciMLBase.successful_retcode(sol)
+end
+
 @testset "Clock system" begin
     dt = 0.1
     @variables x(t) y(t) u(t) yd(t) ud(t) r(t) z(t)