Utilities

Several convenience methods are included for plotting, checking models, and converting results.

Plotting

Basic plotting includes a recipe for Plots.jl for plotting results.

One additional argument is columns for specifying which columns to plot. This can be a vector of integer column positions or names of channels.

plot

Plots.plot — Function.
plot(y::SimResult)

Plot y with options. For detailed options, see the Plots.jl documentation.

using Plots
v = sim(Sims.Examples.Basics.Vanderpol(), 10.0)
plot(v)
z = sim(Sims.Examples.Lib.CauerLowPassAnalog(), 60.0)
plot(z)
plot(z, layout = 1, legend = true)
plot(z, columns = [2,4])
plot(z, columns = 2:4)
plot(z, columns = ["n1", "n2"])
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Miscellaneous

@unknown

Sims.@unknown — Macro.

A macro to ease entry of many unknowns.

@unknown a1 a2 a3 ...

Arguments

  • a : various representations of Unknowns:

    • symbol: equivalent to symbol = Unknown()

    • symbol(val): equivalent to symbol = Unknown(symbol, val)

    • symbol(x, y, z): equivalent to symbol = Unknown(x, y, z)

For `symbol(

Effects

Creates one or more Unknowns

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check

Sims.check — Function.

Prints the number of equations and the number of unknowns.

check(x)

Arguments

  • x : a Model, EquationSet, Sim, or SimState

Returns

  • Nvar : Number of floating point variables

  • Neq : Number of equations

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initialize!

Sims.initialize! — Function.

Experimental function to initialize models. CURRENTLY BROKEN!

initialize!(ss::SimState)

Arguments

  • ss::SimState : the SimState to be initialized

Returns

  • ::JuMP.Model

Details

initialize! updates ss.y0 and ss.yp0 with values that satisfy the initial equations. If it does not converge, a warning is printed, and ss is not changed.

JuMP.jl must be installed along with a nonlinear solver like Ipopt.jl or NLopt.jl. The JuMP model is set up without an objective function. Linear equality constraints are added for each fixed variable. Nonlinear equality constraints are added for each equation in the model (with some additional checking work, some of these could probably be converted to linear constraints).

Also, initialize! only works for scalar models. Models with Unknown vector components don't work. Internally, .* is replaced with *. It's rather kludgy, but right now, JuMP doesn't support .*. A better approach might be to fully flatten the model.

initialize! only runs at the beginning of simulations. It does not run after Events.

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