Merge pull request #3105 from AayushSabharwal/as/callable-params-topsort

fix: handle unknowns inside callable parameters when topsorting equations

Project.toml

@@ -126,7 +126,7 @@ SpecialFunctions = "0.7, 0.8, 0.9, 0.10, 1.0, 2"
 StaticArrays = "0.10, 0.11, 0.12, 1.0"
 SymbolicIndexingInterface = "0.3.31"
 SymbolicUtils = "3.7"
-Symbolics = "6.12"
+Symbolics = "6.14"
 URIs = "1"
 UnPack = "0.1, 1.0"
 Unitful = "1.1"

src/utils.jl

@@ -383,6 +383,14 @@ function vars!(vars, eq::Equation; op = Differential)
 end
 function vars!(vars, O; op = Differential)
     if isvariable(O)
+        if iscalledparameter(O)
+            f = getcalledparameter(O)
+            push!(vars, f)
+            for arg in arguments(O)
+                vars!(vars, arg; op)
+            end
+            return vars
+        end
         return push!(vars, O)
     end
     if symbolic_type(O) == NotSymbolic() && O isa AbstractArray

test/structural_transformation/utils.jl

@@ -32,3 +32,11 @@ se = collect(StructuralTransformations.edges(graph))
 @test se == mapreduce(vcat, enumerate(graph.fadjlist)) do (s, d)
     StructuralTransformations.BipartiteEdge.(s, d)
 end
+
+@testset "observed2graph handles unknowns inside callable parameters" begin
+    @variables x(t) y(t)
+    @parameters p(..)
+    g, _ = ModelingToolkit.observed2graph([y ~ p(x), x ~ 0], [y, x])
+    @test ModelingToolkit.𝑠neighbors(g, 1) == [2]
+    @test ModelingToolkit.𝑑neighbors(g, 2) == [1]
+end