feat: implement is_unused_var for TearingState

AayushSabharwal · AayushSabharwal · commit 4f40ac928e33 · 2026-03-31T19:27:45.000+05:30
diff --git a/lib/ModelingToolkitTearing/src/stateselection_interface.jl b/lib/ModelingToolkitTearing/src/stateselection_interface.jl
@@ -363,3 +363,6 @@ function StateSelection.rm_eqs_vars!(
     return old_to_new_eq, old_to_new_var
 end
 
+function StateSelection.is_unused_var(state::TearingState, var::Integer)
+    return !state.always_present[var] && isempty(𝑑neighbors(state.structure.graph, var))
+end
