Quickstart

There are three ways to interact with OpenModelica:

ModelicaSystem: A Julia style scripting API that handles low level API calls.
OMJulia.API: A Julia style scripting API that handles low level sendExpression calls and has some degree of error handling.
Scripting API with sendExpression: Send expressions to the low level OpenModelica scripting API.

The following examples demonstrate how to simulate Modelica model BouncingBall in both ways.

model BouncingBall
  parameter Real e=0.7 "coefficient of restitution";
  parameter Real g=9.81 "gravity acceleration";
  Real h(fixed=true, start=1) "height of ball";
  Real v(fixed=true) "velocity of ball";
  Boolean flying(fixed=true, start=true) "true, if ball is flying";
  Boolean impact;
  Real v_new(fixed=true);
  Integer foo;
equation
  impact = h <= 0.0;
  foo = if impact then 1 else 2;
  der(v) = if flying then -g else 0;
  der(h) = v;

  when {h <= 0.0 and v <= 0.0,impact} then
    v_new = if edge(impact) then -e*pre(v) else 0;
    flying = v_new > 0;
    reinit(v, v_new);
  end when;
end BouncingBall;

Info

The BouncingBall.mo file can be found in your OpenModelica installation directory in <OpenModelcia>/share/doc/omc/testmodels/BouncingBall.mo.

ModelicaSystem

Start a new OMJulia.OMCSession and create a new ModelicaSystem to build and simulate the BouncingBall model. Afterwards the result can be plotted in Julia.

julia> using OMJulia
julia> using CSV, DataFrames, PlotlyJS
julia> mod = OMJulia.OMCSession();[ Info: Path to zmq file="/tmp/openmodelica.runner.port.julia.uuPiwroA8N"
julia> installDir = sendExpression(mod, "getInstallationDirectoryPath()")"/usr/bin/.."
julia> bouncingBallFile = joinpath(installDir, "share", "doc", "omc", "testmodels", "BouncingBall.mo")"/usr/bin/../share/doc/omc/testmodels/BouncingBall.mo"
julia> ModelicaSystem(mod,
                      bouncingBallFile,
                      "BouncingBall")
julia> simulate(mod,
                resultfile = "BouncingBall_ref.csv",
                simflags   = "-override=outputFormat=csv,stopTime=3")
julia> resultfile = joinpath(getWorkDirectory(mod), "BouncingBall_ref.csv")"/tmp/jl_Avk2Af/BouncingBall_ref.csv"
julia> df = DataFrame(CSV.File(resultfile));
julia> plt = plot(df,
                  x=:time, y=:h,
                  mode="lines",
                  Layout(title="Bouncing Ball", height = 700))data: [
  "scatter with fields mode, type, x, xaxis, y, and yaxis"
]

layout: "layout with fields height, legend, margin, template, title, xaxis, and yaxis"
julia> OMJulia.quit(mod)

OMJulia.API

Example

Start a new OMJulia.OMCSession and call scripting API directly using the OMJulia.API module.

julia> using OMJulia
julia> using OMJulia.API: API
julia> using CSV, DataFrames, PlotlyJS
julia> omc = OMJulia.OMCSession();[ Info: Path to zmq file="/tmp/openmodelica.runner.port.julia.nDyBThtsrG"
julia> installDir = API.getInstallationDirectoryPath(omc)"/usr/bin/.."
julia> bouncingBallFile = joinpath(installDir, "share", "doc", "omc", "testmodels", "BouncingBall.mo")"/usr/bin/../share/doc/omc/testmodels/BouncingBall.mo"
julia> API.loadFile(omc, bouncingBallFile)true
julia> res = API.simulate(omc, "BouncingBall"; stopTime=3.0, outputFormat = "csv")Dict{String, Any} with 10 entries:
  "timeCompile"       => 0.943306
  "simulationOptions" => "startTime = 0.0, stopTime = 3.0, numberOfIntervals = …
  "messages"          => "LOG_SUCCESS       | info    | The initialization fini…
  "timeFrontend"      => 0.0022798
  "timeTotal"         => 0.972704
  "timeTemplates"     => 0.00202762
  "timeSimulation"    => 0.0161775
  "resultFile"        => "/home/runner/work/OMJulia.jl/OMJulia.jl/BouncingBall_…
  "timeSimCode"       => 0.00491671
  "timeBackend"       => 0.00389011
julia> resultfile = res["resultFile"]"/home/runner/work/OMJulia.jl/OMJulia.jl/BouncingBall_res.csv"
julia> df = DataFrame(CSV.File(resultfile));
julia> plt = plot(df,
                  x=:time, y=:h,
                  mode="lines",
                  Layout(title="Bouncing Ball", height = 700))data: [
  "scatter with fields mode, type, x, xaxis, y, and yaxis"
]

layout: "layout with fields height, legend, margin, template, title, xaxis, and yaxis"
julia> OMJulia.quit(omc)

Scripting API with sendExpression

Start a new OMJulia.OMCSession and send scripting API expressions to the omc session with sendExpression().

Warn

All special characters inside a string argument for an API function need to be escaped when passing to sendExpression.

E.g. MOS command

loadFile("/some/path/to/BouncingBall.mo");

becomes Julia code

sendExpression(omc, "loadFile(\"/some/path/to/BouncingBall.mo\")")

Info

On Windows path separation symbol \ needs to be escaped \\ or replaced to Unix style path / to prevent warnings.

julia> using OMJulia
julia> omc = OMJulia.OMCSession();[ Info: Path to zmq file="/tmp/openmodelica.runner.port.julia.wq7ftBPaA7"
julia> installDir = sendExpression(omc, "getInstallationDirectoryPath()")"/usr/bin/.."
julia> bouncingBallFile = joinpath(installDir, "share", "doc", "omc", "testmodels", "BouncingBall.mo")"/usr/bin/../share/doc/omc/testmodels/BouncingBall.mo"
julia> if Sys.iswindows()
           bouncingBallFile = replace(bouncingBallFile, "\\" => "/")
       end
julia> sendExpression(omc, "loadFile(\"$(bouncingBallFile)\")")true
julia> sendExpression(omc, "simulate(BouncingBall)")Dict{String, Any} with 10 entries:
  "timeCompile"       => 0.965267
  "simulationOptions" => "startTime = 0.0, stopTime = 1.0, numberOfIntervals = …
  "messages"          => "LOG_SUCCESS       | info    | The initialization fini…
  "timeFrontend"      => 0.00223665
  "timeTotal"         => 0.992586
  "timeTemplates"     => 0.00227051
  "timeSimulation"    => 0.0140609
  "resultFile"        => "/home/runner/work/OMJulia.jl/OMJulia.jl/docs/omc-temp…
  "timeSimCode"       => 0.0010661
  "timeBackend"       => 0.00757906
julia> OMJulia.quit(omc)