multiply Source + Decide in a simulation

[tamas-p]

Alexander, I was able to create a simulation of one Source (a machine) producing Clients (app triggers) that then are according to the transfer rates set in a Decide node are changed to specific Client types (application types). A simplified version of the model:

I need to add more Sources (machines) to my simulation that will have different transfer rate settings in the Decide node:

Adding them manually as in this model above is certainly possible, but this does not scale well: Copy/paste/adjust method itself is cumbersome, hence only a low number of Sources of clients could be managed this way,

Is there a way to somehow multiply the first Source + Decide and parametirezed them from a table?

[A-Herzog]

Hi Tamas,

if I understand your question correctly, you are looking for a way to simplify the source-decide-assign parts of the model? If your source stations do not have too complicated inter-arrival time definitions, you can try multi-source stations.

Multi-source:
At the moment, the clients arrive at the source station due to the inter-arrival time distribution, are then split into three lanes and have new client types there. If you are using the exponential distribution for the inter-arrival times (e.g. the arrivals are independent), then you have a Poisson process. Joining and splitting Poisson processes results in Poisson processes again. This means if you have an average inter-arrival time of E[I]=1/lambda at the source station (e.g. exp(lambda)), then the inter-arrival times at the three assignment stations are exp(lambda/3) each (or E[I_local]=3*E[I_global]).

A multi-source is a station which just combines multiple source records. The edit dialog shows a table where records can be added. Each record corresponds to a source station. So, you can create your App1, App2 and App3 arrivals at a single station.

But if you are using your source stations to map some complex arrival processes (for example number per interval etc.) and you do not want to break this down to direct arrivals for the three client types, then your current approach is the simplest solution.

Parametirezed copy:
If you copy and paste a single station and the station name ends with a number or with a single letter separated by a space, Warteschlangensimulator will rename the copy automatically (“Clients 1” -> “Clients 2”), see menu item Edit->Rename stations on copy. But the intelligence of this function is limited and it will only work on copy&paste of single stations.

Big automated model changes:
Complex and automated changes to the model would require some user-defined program code to be executed on copy to describe what to do. It does not make much sense to try to include a system trying to cover all possible options in the simulator itself. But the model files of Warteschlangensimulator are plain xml files. So if you want to build really big models in an automated (e.g. defined by program code) way, you can process these files with any programming language. If you have defined a template section in the graphical editor, it should be easy to replicate this section multiple times with adjusted settings. All you need to take care of are the id attributes of the stations and edges. All ids have to be unique. The ids are used to bound the edges to the stations.

Templates:
Another may useful option would be to use the template function in the simulator itself (see template menu item in the model menu). From there you can insert a partial model repeated to the model. But this does not allow any parameterized and automated changes to the partial models on insert.

If you have any specific idea how to realize a parameterized complex copy in a general useable way, just tell me and I will try to add it to the feature wish list for the next versions.

Greetings,
Alexander

[tamas-p]

Thanks a lot for the quick reply! I will start along the lines of your suggestion with the multi-source.