Description
using ModelingToolkitStandardLibrary.Electrical, ModelingToolkit, OrdinaryDiffEq
using ModelingToolkitStandardLibrary.Electrical: Ground, Resistor, VoltageSensor, VoltageSource, Pin
using ModelingToolkitStandardLibrary.Blocks: SmoothSineFunction
# VoltageSource and SmoothSineFunction from this PR <https://github.com/SciML/ModelingToolkitStandardLibrary.jl/pull/18/files>
function StepFunction(;name, offset=0.0, starttime=0.0, height=1.0)
o, st, h = offset, starttime, height
@parameters offset starttime height
@variables y(t)
eqs = [
y ~ offset + h * (t > st)
]
defaults = Dict(zip((offset, starttime, height), (o, st, h)))
ODESystem(eqs, t, [y], [offset, starttime, height],
defaults=defaults, name=name)
# continuous_events=[t ~ st] => [y ~ h])
end
st = 0.5
@parameters t
@named ground = Ground()
@named resistor = Resistor()
@named source = VoltageSource()
@named stepp = StepFunction(offset=0.4, starttime=0.5, height=4)
@named voltage_sensor = VoltageSensor()
rc_eqs = [
source.v ~ stepp.y
connect(source.p, resistor.p, voltage_sensor.p)
connect(voltage_sensor.n, source.n, resistor.n, ground.g)
]
@named rc_model = ODESystem(rc_eqs, t, systems = [resistor, stepp,
source, voltage_sensor, ground],
continuous_events = [t ~ st] => [source.v ~ h]
)
sys = structural_simplify(rc_model)
prob(ODEProblem(sys, u0, (0, 2.0))results LoadError: BoundsError: attempt to access 13-element Vector{Function} at index [] Stacktrace:
The ModelingToolkit.continuous_events(sys) has following output
13-element Vector{ModelingToolkit.SymbolicContinuousCallback}:
ModelingToolkit.SymbolicContinuousCallback(Equation[t ~ 0.5], Equation[source₊v(t) ~ 2.5])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
ModelingToolkit.SymbolicContinuousCallback(Equation[], Equation[])
This no. 13 represents the no. of components used (5 directly in the rc_eqs and the Pins that connect them. Specifying a continuous_events for each of the used component fixes this issue. But a continuous_events for Pin doesn't seem like a necessity.
Sidenote: Even a dummy like continuous_events=1~0 at the component level by-passes the above error
Also, @variables in lower level continuous events must be mentioned in the final model (here rc_model).
For example, in the StepFunction above if continuous_events, instead of t which is passed to rc_model, is defined for y or any new variable then eventual solve throws LoadError: UndefVarError: stepp₊y not defined