Merge branch 'master' into id-tutorial

Author: iliailmer

Project.toml

@@ -1,7 +1,7 @@
 name = "ModelingToolkit"
 uuid = "961ee093-0014-501f-94e3-6117800e7a78"
 authors = ["Chris Rackauckas <[email protected]>"]
-version = "6.4.6"
+version = "6.4.8"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"
@@ -72,7 +72,7 @@ SciMLBase = "1.3"
 Setfield = "0.7"
 SpecialFunctions = "0.7, 0.8, 0.9, 0.10, 1.0"
 StaticArrays = "0.10, 0.11, 0.12, 1.0"
-SymbolicUtils = "0.12, 0.13"
+SymbolicUtils = "0.13.4"
 Symbolics = "3.1"
 UnPack = "0.1, 1.0"
 Unitful = "1.1"

docs/src/basics/FAQ.md

@@ -21,3 +21,25 @@ lowered array? You can use the internal function `varmap_to_vars`. For example:
 ```julia
 pnew = varmap_to_vars([β=>3.0, c=>10.0, γ=>2.0],parameters(sys))
 ```
+
+## How do I handle `if` statements in my symbolic forms?
+
+For statements that are in the `if then else` form, use `IfElse.ifelse` from the
+[IfElse.jl](https://github.com/SciML/IfElse.jl) package to represent the code in a
+functional form. For handling direct `if` statements, you can use equivalent boolean
+mathematical expressions. For example `if x > 0 ...` can be implementated as just
+`(x > 0) * `, where if `x <= 0` then the boolean will evaluate to `0` and thus the
+term will be excluded from the model.
+
+## ERROR: TypeError: non-boolean (Num) used in boolean context?
+
+If you see the error:
+
+```julia
+ERROR: TypeError: non-boolean (Num) used in boolean context
+```
+
+then it's likely you are trying to trace through a function which cannot be
+directly represented in Julia symbols. The techniques to handle this problem,
+such as `@register`, are described in detail 
+[in the Symbolics.jl documentation](https://symbolics.juliasymbolics.org/dev/manual/faq/#Transforming-my-function-to-a-symbolic-equation-has-failed.-What-do-I-do?-1).

src/systems/abstractsystem.jl

@@ -948,7 +948,7 @@ by default.
 function extend(sys::AbstractSystem, basesys::AbstractSystem; name::Symbol=nameof(sys))
     T = SciMLBase.parameterless_type(basesys)
     ivs = independent_variables(basesys)
-    if !(typeof(sys) <: T)
+    if !(sys isa T)
         if length(ivs) == 0
             sys = convert_system(T, sys)
         elseif length(ivs) == 1
@@ -958,11 +958,11 @@ function extend(sys::AbstractSystem, basesys::AbstractSystem; name::Symbol=nameo
         end
     end
 
-    eqs = union(equations(basesys), equations(sys))
-    sts = union(states(basesys), states(sys))
-    ps = union(parameters(basesys), parameters(sys))
-    obs = union(observed(basesys), observed(sys))
-    defs = merge(defaults(basesys), defaults(sys)) # prefer `sys`
+    eqs = union(get_eqs(basesys), get_eqs(sys))
+    sts = union(get_states(basesys), get_states(sys))
+    ps = union(get_ps(basesys), get_ps(sys))
+    obs = union(get_observed(basesys), get_observed(sys))
+    defs = merge(get_defaults(basesys), get_defaults(sys)) # prefer `sys`
     syss = union(get_systems(basesys), get_systems(sys))
 
     if length(ivs) == 0
@@ -984,7 +984,7 @@ function compose(sys::AbstractSystem, systems::AbstractArray{<:AbstractSystem};
     nsys = length(systems)
     nsys >= 1 || throw(ArgumentError("There must be at least 1 subsystem. Got $nsys subsystems."))
     @set! sys.name = name
-    @set! sys.systems = systems
+    @set! sys.systems = [get_systems(sys); systems]
     return sys
 end
 compose(syss::AbstractSystem...; name=nameof(first(syss))) = compose(first(syss), collect(syss[2:end]); name=name)

src/systems/diffeqs/odesystem.jl

@@ -125,7 +125,7 @@ function ODESystem(
         Base.depwarn("`default_u0` and `default_p` are deprecated. Use `defaults` instead.", :ODESystem, force=true)
     end
     defaults = todict(defaults)
-    defaults = Dict(value(k) => value(v) for (k, v) in pairs(defaults))
+    defaults = Dict{Any,Any}(value(k) => value(v) for (k, v) in pairs(defaults))
 
     iv′ = value(scalarize(iv))
     dvs′ = value.(scalarize(dvs))
@@ -187,6 +187,7 @@ end
 
 # NOTE: equality does not check cached Jacobian
 function Base.:(==)(sys1::ODESystem, sys2::ODESystem)
+    sys1 === sys2 && return true
     iv1 = get_iv(sys1)
     iv2 = get_iv(sys2)
     isequal(iv1, iv2) &&

src/systems/nonlinear/nonlinearsystem.jl

@@ -85,7 +85,7 @@ function NonlinearSystem(eqs, states, ps;
     end
     jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
     defaults = todict(defaults)
-    defaults = Dict(value(k) => value(v) for (k, v) in pairs(defaults))
+    defaults = Dict{Any,Any}(value(k) => value(v) for (k, v) in pairs(defaults))
 
     states = collect(states)
     states, ps = value.(states), value.(ps)

src/utils.jl

@@ -216,7 +216,7 @@ function check_operator_variables(eq, op::Type, expr=eq.rhs)
     if operation(expr) isa op
         throw_invalid_operator(expr, eq, op)
     end
-    foreach(expr -> check_operator_variables(eq, op, expr), arguments(expr))
+    foreach(expr -> check_operator_variables(eq, op, expr), SymbolicUtils.unsorted_arguments(expr))
 end
 
 isdifferential(expr) = istree(expr) && operation(expr) isa Differential

test/components.jl

@@ -47,3 +47,11 @@ sol = solve(prob, Rodas4())
 
 prob = ODAEProblem(sys, u0, (0, 10.0))
 sol = solve(prob, Tsit5())
+
+@variables t x1(t) x2(t) x3(t) x4(t)
+D = Differential(t)
+@named sys1_inner = ODESystem([D(x1) ~ x1], t)
+@named sys1_partial = compose(ODESystem([D(x2) ~ x2], t; name=:foo), sys1_inner)
+@named sys1 = extend(ODESystem([D(x3) ~ x3], t; name=:foo), sys1_partial)
+@named sys2 = compose(ODESystem([D(x4) ~ x4], t; name=:foo), sys1)
+@test_nowarn sys2.sys1.sys1_inner.x1 # test the correct nesting