ModelingToolkit.jl No easy to read label for plot without explicit vars argument

If I run the copy&paste examples, such as https://mtk.sciml.ai/stable/tutorials/acausal_components/ :

using ModelingToolkit, Plots, DifferentialEquations

@variables t
@connector function Pin(;name)
    sts = @variables v(t)=1.0 i(t)=1.0 [connect = Flow]
    ODESystem(Equation[], t, sts, []; name=name)
end

function Ground(;name)
    @named g = Pin()
    eqs = [g.v ~ 0]
    compose(ODESystem(eqs, t, [], []; name=name), g)
end

function OnePort(;name)
    @named p = Pin()
    @named n = Pin()
    sts = @variables v(t)=1.0 i(t)=1.0
    eqs = [
           v ~ p.v - n.v
           0 ~ p.i + n.i
           i ~ p.i
          ]
    compose(ODESystem(eqs, t, sts, []; name=name), p, n)
end

function Resistor(;name, R = 1.0)
    @named oneport = OnePort()
    @unpack v, i = oneport
    ps = @parameters R=R
    eqs = [
           v ~ i * R
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

function Capacitor(;name, C = 1.0)
    @named oneport = OnePort()
    @unpack v, i = oneport
    ps = @parameters C=C
    D = Differential(t)
    eqs = [
           D(v) ~ i / C
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

function ConstantVoltage(;name, V = 1.0)
    @named oneport = OnePort()
    @unpack v = oneport
    ps = @parameters V=V
    eqs = [
           V ~ v
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

R = 1.0
C = 1.0
V = 1.0
@named resistor = Resistor(R=R)
@named capacitor = Capacitor(C=C)
@named source = ConstantVoltage(V=V)
@named ground = Ground()

rc_eqs = [
          connect(source.p, resistor.p)
          connect(resistor.n, capacitor.p)
          connect(capacitor.n, source.n)
          connect(capacitor.n, ground.g)
         ]

@named _rc_model = ODESystem(rc_eqs, t)
@named rc_model = compose(_rc_model,
                          [resistor, capacitor, source, ground])
sys = structural_simplify(rc_model)
u0 = [
      capacitor.v => 0.0
     ]
prob = ODAEProblem(sys, u0, (0, 10.0))
sol = solve(prob, Tsit5())
plot(sol)

the tutorial on the website shows that the plot has a meaningful label: correct_plot

While if I run locally, the plot label is a generic integer: wrong_plot

If I explicitly call plot(sol, vars=[capacitor.v]) the label of the plot is correct: less_wrong

I am not sure if the problem is strictly related to ModelingToolkit.jl, but I did not know where to open the issue otherwise.

Status of installed packages:

      Status `~/.julia/environments/v1.7/Project.toml`
  [0c46a032] DifferentialEquations v7.1.0
  [961ee093] ModelingToolkit v8.3.2
  [91a5bcdd] Plots v1.25.6
  [0c5d862f] Symbolics v4.3.0

Jan 23 '22 15:01 traversaro

It's probably the default handling in SciMLBase that needs an update.

https://github.com/SciML/SciMLBase.jl/blob/v1.26.0/src/solutions/solution_interface.jl#L158

Jan 23 '22 16:01 ChrisRackauckas

I think this can close now. plot_1

version 1.78.0

name = "SciMLBase"
uuid = "0bca4576-84f4-4d90-8ffe-ffa030f20462"
authors = ["Chris Rackauckas <[email protected]> and contributors"]
version = "1.78.0"

[deps]
ArrayInterfaceCore = "30b0a656-2188-435a-8636-2ec0e6a096e2"
CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"
ConstructionBase = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
DifferentialEquations = "0c46a032-eb83-5123-abaf-570d42b7fbaa"
Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
EnumX = "4e289a0a-7415-4d19-859d-a7e5c4648b56"
FunctionWrappersWrappers = "77dc65aa-8811-40c2-897b-53d922fa7daf"
IteratorInterfaceExtensions = "82899510-4779-5014-852e-03e436cf321d"
LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
Preferences = "21216c6a-2e73-6563-6e65-726566657250"
RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
RuntimeGeneratedFunctions = "7e49a35a-f44a-4d26-94aa-eba1b4ca6b47"
StaticArraysCore = "1e83bf80-4336-4d27-bf5d-d5a4f845583c"
Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"

[compat]
ArrayInterfaceCore = "0.1.1"
CommonSolve = "0.2"
ConstructionBase = "1"
DocStringExtensions = "0.8, 0.9"
EnumX = "1"
FunctionWrappersWrappers = "0.1"
IteratorInterfaceExtensions = "^0.1, ^1"
Preferences = "1.3"
RecipesBase = "0.7.0, 0.8, 1.0"
RecursiveArrayTools = "2.14"
RuntimeGeneratedFunctions = "0.5"
StaticArrays = "1"
StaticArraysCore = "1"
Tables = "1"
julia = "1.6"

[extras]
DelayDiffEq = "bcd4f6db-9728-5f36-b5f7-82caef46ccdb"
OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
StochasticDiffEq = "789caeaf-c7a9-5a7d-9973-96adeb23e2a0"
Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

[targets]
test = ["Pkg", "SafeTestsets", "Test", "StaticArrays"]

Code is the same

using ModelingToolkit, Plots, DifferentialEquations


@variables t
@connector function Pin(;name)
    sts = @variables v(t)=1.0 i(t)=1.0 [connect = Flow]
    ODESystem(Equation[], t, sts, []; name=name)
end

function Ground(;name)
    @named g = Pin()
    eqs = [g.v ~ 0]
    compose(ODESystem(eqs, t, [], []; name=name), g)
end

function OnePort(;name)
    @named p = Pin()
    @named n = Pin()
    sts = @variables v(t)=1.0 i(t)=1.0
    eqs = [
           v ~ p.v - n.v
           0 ~ p.i + n.i
           i ~ p.i
          ]
    compose(ODESystem(eqs, t, sts, []; name=name), p, n)
end

function Resistor(;name, R = 1.0)
    @named oneport = OnePort()
    @unpack v, i = oneport
    ps = @parameters R=R
    eqs = [
           v ~ i * R
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

function Capacitor(;name, C = 1.0)
    @named oneport = OnePort()
    @unpack v, i = oneport
    ps = @parameters C=C
    D = Differential(t)
    eqs = [
           D(v) ~ i / C
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

function ConstantVoltage(;name, V = 1.0)
    @named oneport = OnePort()
    @unpack v = oneport
    ps = @parameters V=V
    eqs = [
           V ~ v
          ]
    extend(ODESystem(eqs, t, [], ps; name=name), oneport)
end

R = 1.0
C = 1.0
V = 1.0
@named resistor = Resistor(R=R)
@named capacitor = Capacitor(C=C)
@named source = ConstantVoltage(V=V)
@named ground = Ground()

rc_eqs = [
          connect(source.p, resistor.p)
          connect(resistor.n, capacitor.p)
          connect(capacitor.n, source.n)
          connect(capacitor.n, ground.g)
         ]

@named _rc_model = ODESystem(rc_eqs, t)
@named rc_model = compose(_rc_model,
                          [resistor, capacitor, source, ground])
sys = structural_simplify(rc_model)
u0 = [
      capacitor.v => 0.0
     ]
prob = ODAEProblem(sys, u0, (0, 10.0))
sol = solve(prob, Tsit5())
plot(sol)

Dec 10 '22 23:12 xlxs4

Thanks a lot!

Dec 11 '22 11:12 traversaro