Anti-places/limit places
How-to


Introduction

Often one would like to limit the capacity for a place, e.g. to model a network buffer, or simply to make the net finite to facilitate the generation of state-spaces.

Unfortunately CPN Tools doen not support this, but this can easily be modelled using the concept of anti-places.

An anti-place is a place corresponding to the original place, where for each arc to/from the original place, there is an arc from/to the anti-place, moving the same number of uncoloured tokens.

Example

image unordered.jpg

This is a very simple model of a sender and a receiver.

The sender, sends packages onto a network.

The receiver receives packages from the network.

Limit the capacity

We would like to limit the capacity of the network to 2.

We add an anti-place with two tokens. When I do this to the above example, I obtain:

image limited.jpg

Adding an anti-place

NOTE: I do not need to add the type "E", as it is one of the standard declarations.

Changes to arcs (incoming and outgoing)

Examples

The examples from this document can be downloaded