feat: mark inputs and outputs of FMU with appropriate metadata

Author: AayushSabharwal

ext/MTKFMIExt.jl

@@ -132,7 +132,8 @@ function MTK.FMIComponent(::Val{Ver}; fmu = nothing, tolerance = 1e-6,
     # parse the inputs to the FMU
     inputs = []
     fmi_variables_to_mtk_variables!(fmu, FMI.getInputValueReferencesAndNames(fmu),
-        value_references, inputs, states, observed)
+        value_references, inputs, states, observed; postprocess_variable = v -> MTK.setinput(
+            v, true))
     # create a symbolic variable for the input buffer
     if isempty(inputs)
         __mtk_internal_x = []
@@ -145,7 +146,8 @@ function MTK.FMIComponent(::Val{Ver}; fmu = nothing, tolerance = 1e-6,
     # parse the outputs of the FMU
     outputs = []
     fmi_variables_to_mtk_variables!(fmu, FMI.getOutputValueReferencesAndNames(fmu),
-        value_references, outputs, states, observed)
+        value_references, outputs, states, observed; postprocess_variable = v -> MTK.setoutput(
+            v, true))
     # create the output buffer. This is only required for CoSimulation to pass it to
     # the callback affect
     if type == :CS
@@ -284,18 +286,22 @@ defaults.
 # Keyword Arguments
 - `parameters`: A boolean indicating whether to use `@parameters` for the symbolic
   variables instead of `@variables`.
+- `postprocess_variable`: A function applied to each created variable that should
+  return the updated variable. This is useful to add metadata to variables.
 """
 function fmi_variables_to_mtk_variables!(
         fmu::Union{FMI.FMU2, FMI.FMU3}, varmap::AbstractDict,
         value_references::AbstractDict, truevars, allvars,
-        obseqs, defs = Dict(); parameters = false)
+        obseqs, defs = Dict(); parameters = false, postprocess_variable = identity)
     for (valRef, snames) in varmap
         stateT = FMI.dataTypeForValueReference(fmu, valRef)
         snames = map(parseFMIVariableName, snames)
         if parameters
-            vars = [MTK.unwrap(only(@parameters $sname::stateT)) for sname in snames]
+            vars = [postprocess_variable(MTK.unwrap(only(@parameters $sname::stateT)))
+                    for sname in snames]
         else
-            vars = [MTK.unwrap(only(@variables $sname(t)::stateT)) for sname in snames]
+            vars = [postprocess_variable(MTK.unwrap(only(@variables $sname(t)::stateT)))
+                    for sname in snames]
         end
         for i in eachindex(vars)
             if i == 1

test/extensions/fmi.jl

@@ -9,9 +9,16 @@ const FMU_DIR = joinpath(@__DIR__, "fmus")
     truesol = FMI.simulate(
         fmu, (0.0, 8.0); saveat = 0.0:0.1:8.0, recordValues = ["mass.s", "mass.v"])
 
+    function test_no_inputs_outputs(sys)
+        for var in unknowns(sys)
+            @test !MTK.isinput(var)
+            @test !MTK.isoutput(var)
+        end
+    end
     @testset "v2, ME" begin
         fmu = loadFMU("SpringPendulum1D", "Dymola", "2022x"; type = :ME)
         @mtkbuild sys = MTK.FMIComponent(Val(2); fmu, type = :ME)
+        test_no_inputs_outputs(sys)
         prob = ODEProblem{true, SciMLBase.FullSpecialize}(
             sys, [sys.mass__s => 0.5, sys.mass__v => 0.0], (0.0, 8.0))
         sol = solve(prob, Tsit5(); reltol = 1e-8, abstol = 1e-8)
@@ -28,6 +35,7 @@ const FMU_DIR = joinpath(@__DIR__, "fmus")
             Val(2); fmu, communication_step_size = 0.001, type = :CS)
         @variables x(t) = 1.0
         @mtkbuild sys = ODESystem([D(x) ~ x], t; systems = [inner])
+        test_no_inputs_outputs(sys)
 
         prob = ODEProblem{true, SciMLBase.FullSpecialize}(
             sys, [sys.inner.mass__s => 0.5, sys.inner.mass__v => 0.0], (0.0, 8.0))
@@ -44,6 +52,7 @@ const FMU_DIR = joinpath(@__DIR__, "fmus")
     @testset "v3, ME" begin
         fmu = loadFMU("SpringPendulum1D", "Dymola", "2023x", "3.0"; type = :ME)
         @mtkbuild sys = MTK.FMIComponent(Val(3); fmu, type = :ME)
+        test_no_inputs_outputs(sys)
         prob = ODEProblem{true, SciMLBase.FullSpecialize}(
             sys, [sys.mass__s => 0.5, sys.mass__v => 0.0], (0.0, 8.0))
         sol = solve(prob, Tsit5(); reltol = 1e-8, abstol = 1e-8)
@@ -60,6 +69,7 @@ const FMU_DIR = joinpath(@__DIR__, "fmus")
             Val(3); fmu, communication_step_size = 0.001, type = :CS)
         @variables x(t) = 1.0
         @mtkbuild sys = ODESystem([D(x) ~ x], t; systems = [inner])
+        test_no_inputs_outputs(sys)
 
         prob = ODEProblem{true, SciMLBase.FullSpecialize}(
             sys, [sys.inner.mass__s => 0.5, sys.inner.mass__v => 0.0], (0.0, 8.0))
@@ -75,6 +85,11 @@ end
     @testset "v2, ME" begin
         fmu = loadFMU(joinpath(FMU_DIR, "SimpleAdder.fmu"); type = :ME)
         @named adder = MTK.FMIComponent(Val(2); fmu, type = :ME)
+        @test MTK.isinput(adder.a)
+        @test MTK.isinput(adder.b)
+        @test MTK.isoutput(adder.out)
+        @test !MTK.isinput(adder.c) && !MTK.isoutput(adder.c)
+
         @variables a(t) b(t) c(t) [guess = 1.0]
         @mtkbuild sys = ODESystem(
             [adder.a ~ a, adder.b ~ b, D(a) ~ t,
@@ -92,6 +107,10 @@ end
         fmu = loadFMU(joinpath(FMU_DIR, "SimpleAdder.fmu"); type = :CS)
         @named adder = MTK.FMIComponent(
             Val(2); fmu, type = :CS, communication_step_size = 0.001)
+        @test MTK.isinput(adder.a)
+        @test MTK.isinput(adder.b)
+        @test MTK.isoutput(adder.out)
+        @test !MTK.isinput(adder.c) && !MTK.isoutput(adder.c)
         @variables a(t) b(t) c(t) [guess = 1.0]
         @mtkbuild sys = ODESystem(
             [adder.a ~ a, adder.b ~ b, D(a) ~ t,
@@ -110,6 +129,9 @@ end
     @testset "v3, ME" begin
         fmu = loadFMU(joinpath(FMU_DIR, "StateSpace.fmu"); type = :ME)
         @named sspace = MTK.FMIComponent(Val(3); fmu, type = :ME)
+        @test MTK.isinput(sspace.u)
+        @test MTK.isoutput(sspace.y)
+        @test !MTK.isinput(sspace.x) && !MTK.isoutput(sspace.x)
         @variables u(t)=1.0 x(t)=1.0 y(t) [guess = 1.0]
         @mtkbuild sys = ODESystem(
             [sspace.u ~ u, D(u) ~ t, D(x) ~ sspace.x + sspace.y, y^2 ~ sspace.y + x], t;
@@ -125,6 +147,9 @@ end
         fmu = loadFMU(joinpath(FMU_DIR, "StateSpace.fmu"); type = :CS)
         @named sspace = MTK.FMIComponent(
             Val(3); fmu, communication_step_size = 1e-3, type = :CS)
+        @test MTK.isinput(sspace.u)
+        @test MTK.isoutput(sspace.y)
+        @test !MTK.isinput(sspace.x) && !MTK.isoutput(sspace.x)
         @variables u(t)=1.0 x(t)=1.0 y(t) [guess = 1.0]
         @mtkbuild sys = ODESystem(
             [sspace.u ~ u, D(u) ~ t, D(x) ~ sspace.x + sspace.y, y^2 ~ sspace.y + x], t;