fix: fix propagation of guesses in hierarchical systems

Author: AayushSabharwal

src/systems/abstractsystem.jl

@@ -859,6 +859,11 @@ function namespace_defaults(sys)
     for (k, v) in pairs(defs))
 end
 
+function namespace_guesses(sys)
+    guess = guesses(sys)
+    Dict(unknowns(sys, k) => namespace_expr(v, sys) for (k, v) in guess)
+end
+
 function namespace_equations(sys::AbstractSystem, ivs = independent_variables(sys))
     eqs = equations(sys)
     isempty(eqs) && return Equation[]
@@ -968,7 +973,13 @@ function full_parameters(sys::AbstractSystem)
 end
 
 function guesses(sys::AbstractSystem)
-    get_guesses(sys)
+    guess = get_guesses(sys)
+    systems = get_systems(sys)
+    isempty(systems) && return guess
+    for subsys in systems
+        guess = merge(guess, namespace_guesses(subsys))
+    end
+    return guess
 end
 
 # required in `src/connectors.jl:437`

src/systems/diffeqs/odesystem.jl

@@ -354,6 +354,7 @@ function flatten(sys::ODESystem, noeqs = false)
             get_iv(sys),
             unknowns(sys),
             parameters(sys),
+            guesses = guesses(sys),
             observed = observed(sys),
             continuous_events = continuous_events(sys),
             discrete_events = discrete_events(sys),

test/odesystem.jl

@@ -1120,3 +1120,15 @@ tearing_state = TearingState(expand_connections(sys))
 ts_vars = tearing_state.fullvars
 orig_vars = unknowns(sys)
 @test isempty(setdiff(ts_vars, orig_vars))
+
+# Guesses in hierarchical systems
+@variables x(t) y(t)
+@named sys = ODESystem(Equation[], t, [x], []; guesses = [x => 1.0])
+@named outer = ODESystem(
+    [D(y) ~ sys.x + t, 0 ~ t + y - sys.x * y], t, [y], []; systems = [sys])
+@test ModelingToolkit.guesses(outer)[sys.x] == 1.0
+outer = structural_simplify(outer)
+@test ModelingToolkit.get_guesses(outer)[sys.x] == 1.0
+prob = ODEProblem(outer, [outer.y => 2.0], (0.0, 10.0))
+int = init(prob, Rodas4())
+@test int[outer.sys.x] == 1.0