Merge pull request #3027 from SciML/double_ss_error

Throw an error if structural simplification is applied twice

Author: ChrisRackauckas

.github/workflows/Tests.yml

@@ -28,6 +28,8 @@ jobs:
         group:
           - InterfaceI
           - InterfaceII
+          - SymbolicIndexingInterface
+          - Extended
           - Extensions
           - Downstream
           - RegressionI

src/systems/systems.jl

@@ -3,6 +3,14 @@ function System(eqs::AbstractVector{<:Equation}, iv, args...; name = nothing,
     ODESystem(eqs, iv, args...; name, kw..., checks = false)
 end
 
+const REPEATED_SIMPLIFICATION_MESSAGE = "Structural simplification cannot be applied to a completed system. Double simplification is not allowed."
+
+struct RepeatedStructuralSimplificationError <: Exception end
+
+function Base.showerror(io::IO, e::RepeatedStructuralSimplificationError)
+    print(io, REPEATED_SIMPLIFICATION_MESSAGE)
+end
+
 """
 $(SIGNATURES)
 
@@ -21,6 +29,7 @@ function structural_simplify(
         sys::AbstractSystem, io = nothing; simplify = false, split = true,
         allow_symbolic = false, allow_parameter = true, conservative = false, fully_determined = true,
         kwargs...)
+    iscomplete(sys) && throw(RepeatedStructuralSimplificationError())
     newsys′ = __structural_simplify(sys, io; simplify,
         allow_symbolic, allow_parameter, conservative, fully_determined,
         kwargs...)

test/downstream/linearize.jl

@@ -312,7 +312,6 @@ matrices = linfun([1.0], Dict(p => 3.0), 1.0)
     @parameters p
     eqs = [0 ~ x * log(y) - p]
     @named sys = ODESystem(eqs, t; defaults = [p => 1.0])
-    sys = complete(sys)
     @test_nowarn linearize(
         sys, [x], []; op = Dict(x => 1.0), allow_input_derivatives = true)
 end

test/initial_values.jl

@@ -114,6 +114,6 @@ end
 @variables x(t)
 @parameters p
 @mtkbuild sys = ODESystem([D(x) ~ p], t; defaults = [x => t, p => 2t])
-prob = ODEProblem(structural_simplify(sys), [], (1.0, 2.0), [])
+prob = ODEProblem(sys, [], (1.0, 2.0), [])
 @test prob[x] == 1.0
 @test prob.ps[p] == 2.0

test/input_output_handling.jl

@@ -362,12 +362,12 @@ disturbed_input = ins[1]
     dist_integ,
     ins)
 
-augmented_sys = complete(augmented_sys)
+getter_sys = complete(augmented_sys)
 matrices, ssys = linearize(augmented_sys,
     [
-        augmented_sys.u,
-        augmented_sys.input.u[2],
-        augmented_sys.d
+        getter_sys.u,
+        getter_sys.input.u[2],
+        getter_sys.d
     ], outs)
 @test matrices.A ≈ [A [1; 0]; zeros(1, 2) -0.001]
 @test matrices.B == I

test/mtkparameters.jl

@@ -144,8 +144,8 @@ function level1()
     eqs = [D(x) ~ p1 * x - p2 * x * y
            D(y) ~ -p3 * y + p4 * x * y]
 
-    sys = structural_simplify(complete(ODESystem(
-        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4])))
+    sys = structural_simplify(ODESystem(
+        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4]))
     prob = ODEProblem{true, SciMLBase.FullSpecialize}(sys)
 end
 
@@ -158,8 +158,8 @@ function level2()
     eqs = [D(x) ~ p1 * x - p23[1] * x * y
            D(y) ~ -p23[2] * y + p4 * x * y]
 
-    sys = structural_simplify(complete(ODESystem(
-        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4])))
+    sys = structural_simplify(ODESystem(
+        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4]))
     prob = ODEProblem{true, SciMLBase.FullSpecialize}(sys)
 end
 
@@ -172,8 +172,8 @@ function level3()
     eqs = [D(x) ~ p1 * x - p23[1] * x * y
            D(y) ~ -p23[2] * y + p4 * x * y]
 
-    sys = structural_simplify(complete(ODESystem(
-        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4])))
+    sys = structural_simplify(ODESystem(
+        eqs, t, tspan = (0, 3.0), name = :sys, parameter_dependencies = [y0 => 2p4]))
     prob = ODEProblem{true, SciMLBase.FullSpecialize}(sys)
 end
 

test/nonlinearsystem.jl

@@ -251,7 +251,6 @@ end
         0 ~ z - cos(x),
         0 ~ x * y]
     @named ns = NonlinearSystem(eqs, [x, y, z], [])
-    ns = complete(ns)
     vs = [unknowns(ns); parameters(ns)]
     ss_mtk = structural_simplify(ns)
     prob = NonlinearProblem(ss_mtk, vs .=> 1.0)

test/reduction.jl

@@ -75,11 +75,6 @@ __x = x
 # Reduced Flattened System
 
 reduced_system = structural_simplify(connected)
-reduced_system2 = structural_simplify(tearing_substitution(structural_simplify(tearing_substitution(structural_simplify(connected)))))
-
-@test isempty(setdiff(unknowns(reduced_system), unknowns(reduced_system2)))
-@test isequal(equations(tearing_substitution(reduced_system)), equations(reduced_system2))
-@test isequal(observed(reduced_system), observed(reduced_system2))
 @test setdiff(unknowns(reduced_system),
     [s
      a

test/runtests.jl

@@ -33,57 +33,62 @@ end
             @safetestset "Unitful Quantities Test" include("units.jl")
             @safetestset "LabelledArrays Test" include("labelledarrays.jl")
             @safetestset "Mass Matrix Test" include("mass_matrix.jl")
-            @safetestset "SteadyStateSystem Test" include("steadystatesystems.jl")
-            @safetestset "SDESystem Test" include("sdesystem.jl")
-            @safetestset "DDESystem Test" include("dde.jl")
-            @safetestset "NonlinearSystem Test" include("nonlinearsystem.jl")
             @safetestset "InitializationSystem Test" include("initializationsystem.jl")
             @safetestset "Guess Propagation" include("guess_propagation.jl")
             @safetestset "Hierarchical Initialization Equations" include("hierarchical_initialization_eqs.jl")
-            @safetestset "PDE Construction Test" include("pde.jl")
-            @safetestset "JumpSystem Test" include("jumpsystem.jl")
-            @safetestset "Constraints Test" include("constraints.jl")
             @safetestset "Reduction Test" include("reduction.jl")
             @safetestset "Split Parameters Test" include("split_parameters.jl")
             @safetestset "StaticArrays Test" include("static_arrays.jl")
             @safetestset "Components Test" include("components.jl")
             @safetestset "Model Parsing Test" include("model_parsing.jl")
-            @safetestset "print_tree" include("print_tree.jl")
             @safetestset "Error Handling" include("error_handling.jl")
             @safetestset "StructuralTransformations" include("structural_transformation/runtests.jl")
             @safetestset "State Selection Test" include("state_selection.jl")
             @safetestset "Symbolic Event Test" include("symbolic_events.jl")
             @safetestset "Stream Connect Test" include("stream_connectors.jl")
             @safetestset "Domain Connect Test" include("domain_connectors.jl")
             @safetestset "Lowering Integration Test" include("lowering_solving.jl")
-            @safetestset "Test Big System Usage" include("bigsystem.jl")
             @safetestset "Dependency Graph Test" include("dep_graphs.jl")
             @safetestset "Function Registration Test" include("function_registration.jl")
             @safetestset "Precompiled Modules Test" include("precompile_test.jl")
-            @safetestset "Variable Utils Test" include("variable_utils.jl")
-            @safetestset "Variable Metadata Test" include("test_variable_metadata.jl")
             @safetestset "DAE Jacobians Test" include("dae_jacobian.jl")
             @safetestset "Jacobian Sparsity" include("jacobiansparsity.jl")
             @safetestset "Modelingtoolkitize Test" include("modelingtoolkitize.jl")
-            @safetestset "OptimizationSystem Test" include("optimizationsystem.jl")
             @safetestset "FuncAffect Test" include("funcaffect.jl")
             @safetestset "Constants Test" include("constants.jl")
             @safetestset "Parameter Dependency Test" include("parameter_dependencies.jl")
             @safetestset "Generate Custom Function Test" include("generate_custom_function.jl")
             @safetestset "Initial Values Test" include("initial_values.jl")
-            @safetestset "Discrete System" include("discrete_system.jl")
             @safetestset "Equation Type Accessors Test" include("equation_type_accessors.jl")
             @safetestset "Equations with complex values" include("complex.jl")
         end
     end
 
-    if GROUP == "All" || GROUP == "InterfaceI" || GROUP == "SymbolicIndexingInterface"
+    if GROUP == "All" || GROUP == "InterfaceII"
+        @testset "InterfaceII" begin
+            @safetestset "Variable Utils Test" include("variable_utils.jl")
+            @safetestset "Variable Metadata Test" include("test_variable_metadata.jl")
+            @safetestset "OptimizationSystem Test" include("optimizationsystem.jl")
+            @safetestset "Discrete System" include("discrete_system.jl")
+            @safetestset "SteadyStateSystem Test" include("steadystatesystems.jl")
+            @safetestset "SDESystem Test" include("sdesystem.jl")
+            @safetestset "DDESystem Test" include("dde.jl")
+            @safetestset "NonlinearSystem Test" include("nonlinearsystem.jl")
+            @safetestset "PDE Construction Test" include("pde.jl")
+            @safetestset "JumpSystem Test" include("jumpsystem.jl")
+            @safetestset "print_tree" include("print_tree.jl")
+            @safetestset "Constraints Test" include("constraints.jl")
+        end
+    end
+
+    if GROUP == "All" || GROUP == "SymbolicIndexingInterface"
         @safetestset "SymbolicIndexingInterface test" include("symbolic_indexing_interface.jl")
         @safetestset "SciML Problem Input Test" include("sciml_problem_inputs.jl")
         @safetestset "MTKParameters Test" include("mtkparameters.jl")
     end
 
-    if GROUP == "All" || GROUP == "InterfaceII"
+    if GROUP == "All" || GROUP == "Extended"
+        @safetestset "Test Big System Usage" include("bigsystem.jl")
         println("C compilation test requires gcc available in the path!")
         @safetestset "C Compilation Test" include("ccompile.jl")
         @testset "Distributed Test" include("distributed.jl")

test/structural_transformation/errors.jl

@@ -0,0 +1,19 @@
+using ModelingToolkit
+using ModelingToolkit: t_nounits as t, D_nounits as D
+using Test
+
+@mtkmodel FOL begin
+    @parameters begin
+        τ = 3.0 # parameters
+    end
+    @variables begin
+        x(t) = 0.0 # dependent variables
+    end
+    @equations begin
+        D(x) ~ (1 - x) / τ
+    end
+end
+
+@named rc_model = FOL()
+sys = structural_simplify(rc_model)
+@test_throws ModelingToolkit.RepeatedStructuralSimplificationError structural_simplify(sys)