Read model variable

[tamas-p]

First of all, thanks for this great tool! I am new to it and also to qeuing in general.
In my project I added a Condition (Script) element and trying the following java code:

void function(SimulationInterface sim) {
    sim.getSystem().log("Where can I see this?");
    sim.getSystem().set("currentCpu", 333); // How can I read the variable?
    sim.getClients().release(0);
}

I can set a new value to a variable (here it is currentCpu - that I initialized in the Model properties dialog) with sim.getSystem().set, but there seems not to be a get counterpart. How can I read the variable?

Also, it seems I can log through sim.getSystem().log, but where can I see this log?

[A-Herzog]

Hi Tamas Palagyi,

Warteschlangensimulator has three different modes for interacting with a model: by probability distributions, by calculation expressions and via scripts. While using probability distributions is the fastest, it’s also the least flexible way. Calculation expressions are more flexible but slower and of course with scripts you can do everything - but the execution will take more time.

In calculation expressions global variables can be used. The names of these variables need to be known at simulation start time. During the simulation the list of variables cannot be extended. Variables can be made known to the system in two different ways: Implicitly by using them as an assignment target at a "Variable" station or explicitly on the "Initial variable values" pages in the model settings dialog. Actual assignments to variable are usually made via "Variable" stations and the values can be used in any calculation expression. (See the example model "Limited number of clients at a station" for example.)

In scripts you can access the calculation expression system via double value=(double)sim.getSystem().calc("variableName"); and sim.getSystem().set("variableName",value);. Again: "variableName" has to be already known to the calculation expression system. So, if you add "currentCpu" on the "Initial variable values" pages, you can use it in your script as a global, permanent available variable.

But if you want to use the variable only in script code (and not in calculation expressions) there is an even more flexible way: sim.getSystem().getMapGlobal() will return a Map<String,Object> where you can store anything (even objects) you want to. You can access this map from all scripts and it has the same content in all scripts.

The strings you send to sim.getSystem().log(...) are written to the event log (at the bottom of the program window when running an animation in single step mode) and to log files when running Simulation|Record simulation to log file... These event logs are mainly intended for debugging purpose. If you just want to output information from a simulation, you can use "Output" or "Output (Script)" stations.

Greetings
Alexander Herzog

[tamas-p]

Thank you for the quick reply! I did not expect such quick answer and started to look for a workaround: I rewrote my little project to use the sim.getSystem().getMapGlobal() that you also suggested. Now I have to make up my mind which way to go as you described how to read the global variables from the calculation expression global variables. Using those global variables seems to have the benefit of being available for both calculation expressions and scripts while the MapGlobal is for only scripts as you explained.
On the other hand, even after few hours I spent with the simulator I started to like scripting and started to feel that it is better to use scipts instead of a specific element e.g. for increasing the value of a variable.