Merge pull request #1861 from SciML/myb/dummy

Mark explicit io when introducing a new variable

Author: YingboMa

src/inputoutput.jl

@@ -354,9 +354,10 @@ The generated dynamics functions `(f_oop, f_ip)` will preserve any state and dyn
 The example below builds a double-mass model and adds an integrating disturbance to the input
 ```julia
 using ModelingToolkit
+using ModelingToolkitStandardLibrary
 using ModelingToolkitStandardLibrary.Mechanical.Rotational
 using ModelingToolkitStandardLibrary.Blocks
-using ModelingToolkitStandardLibrary.Blocks: t
+t = ModelingToolkitStandardLibrary.Blocks.t
 
 # Parameters
 m1 = 1

src/structural_transformation/StructuralTransformations.jl

@@ -22,7 +22,7 @@ using ModelingToolkit: ODESystem, AbstractSystem, var_from_nested_derivative, Di
                        get_postprocess_fbody, vars!,
                        IncrementalCycleTracker, add_edge_checked!, topological_sort,
                        invalidate_cache!, Substitutions, get_or_construct_tearing_state,
-                       AliasGraph, filter_kwargs
+                       AliasGraph, filter_kwargs, lower_varname, setio
 
 using ModelingToolkit.BipartiteGraphs
 import .BipartiteGraphs: invview

src/structural_transformation/symbolics_tearing.jl

@@ -269,7 +269,7 @@ function tearing_reassemble(state::TearingState, var_eq_matching; simplify = fal
         if var_eq_matching[var] !== SelectedState()
             dd = fullvars[dv]
             if (i_v_t = get(possible_x_t, dd, nothing)) === nothing
-                v_t = diff2term(unwrap(dd))
+                v_t = setio(diff2term(unwrap(dd)), false, false)
             else
                 idx, v_t = i_v_t
                 push!(removed_obs, idx)
@@ -423,7 +423,7 @@ function tearing_reassemble(state::TearingState, var_eq_matching; simplify = fal
             if (i_x_t = get(possible_x_t, dx, nothing)) === nothing &&
                (ogidx !== nothing &&
                 (i_x_t = get(possible_x_t, fullvars[ogidx], nothing)) === nothing)
-                x_t = ModelingToolkit.lower_varname(ogx, iv, o)
+                x_t = setio(lower_varname(ogx, iv, o), false, false)
             else
                 idx, x_t = i_x_t
                 push!(removed_obs, idx)

src/systems/abstractsystem.jl

@@ -1109,18 +1109,15 @@ function markio!(state, inputs, outputs; check = true)
     outputset = Dict(outputs .=> false)
     for (i, v) in enumerate(fullvars)
         if v in keys(inputset)
-            v = setmetadata(v, ModelingToolkit.VariableInput, true)
-            v = setmetadata(v, ModelingToolkit.VariableOutput, false)
+            v = setio(v, true, false)
             inputset[v] = true
             fullvars[i] = v
         elseif v in keys(outputset)
-            v = setmetadata(v, ModelingToolkit.VariableInput, false)
-            v = setmetadata(v, ModelingToolkit.VariableOutput, true)
+            v = setio(v, false, true)
             outputset[v] = true
             fullvars[i] = v
         else
-            v = setmetadata(v, ModelingToolkit.VariableInput, false)
-            v = setmetadata(v, ModelingToolkit.VariableOutput, false)
+            v = setio(v, false, false)
             fullvars[i] = v
         end
     end

src/variables.jl

@@ -26,6 +26,9 @@ function isvarkind(m, x)
     getmetadata(x, m, false)
 end
 
+setinput(x, v) = setmetadata(x, VariableInput, v)
+setoutput(x, v) = setmetadata(x, VariableOutput, v)
+setio(x, i, o) = setoutput(setinput(x, i), o)
 isinput(x) = isvarkind(VariableInput, x)
 isoutput(x) = isvarkind(VariableOutput, x)
 isirreducible(x) = isvarkind(VariableIrreducible, x) || isinput(x)

test/input_output_handling.jl

@@ -108,6 +108,24 @@ syss = structural_simplify(sys2)
 #@test isequal(unbound_outputs(syss), [y])
 @test isequal(bound_outputs(syss), [sys.y])
 
+using ModelingToolkitStandardLibrary
+using ModelingToolkitStandardLibrary.Mechanical.Rotational
+t = ModelingToolkitStandardLibrary.Mechanical.Rotational.t
+@named inertia1 = Inertia(; J = 1)
+@named inertia2 = Inertia(; J = 1)
+@named spring = Spring(; c = 10)
+@named damper = Damper(; d = 3)
+@named torque = Torque()
+eqs = [connect(torque.flange, inertia1.flange_a)
+       connect(inertia1.flange_b, spring.flange_a, damper.flange_a)
+       connect(inertia2.flange_a, spring.flange_b, damper.flange_b)]
+model = ODESystem(eqs, t; systems = [torque, inertia1, inertia2, spring, damper],
+                  name = :name)
+model_outputs = [inertia1.w, inertia2.w, inertia1.phi, inertia2.phi]
+model_inputs = [torque.tau.u]
+matrices, ssys = linearize(model, model_inputs, model_outputs)
+@test length(ModelingToolkit.outputs(ssys)) == 4
+
 ## Code generation with unbound inputs
 
 @variables t x(t)=0 u(t)=0 [input = true]