Much Faster Simulation Engine

We have made a total redesign of the Standard ML code used for simulation. This means that simulations of complex CPN models is often as as much as 1000 times faster -- in particular for models with many tokens and models with time. Such models can now be run in a few seconds instead of hours.

To obtain the new simulation engine, several changes have been done:

The data structures for multi-sets are changed from lists to a particular kind of self-balancing trees (when Design/CPN was created in 1989 no one thought that people would use it for models having places with thousands of tokens).
Priority queues are used for timed simulations.
The transition scheduler is modified to make a more efficient search for enabled transitions - without losing fairness.
The functions that calculate the set of enabled bindings of a transition are significantly improved.

The new simulation engine is used for automatic simulations, i.e fast simulations with no visual feedback of the token game. Manual simulations and generation of occurrence graphs are still done by means of the old simulation engine which remains part of the Design/CPN tool.

The new simulation engine has been used in a number of internal projects at University of Aarhus. However, this is the first external release. This means that users must be prepared to experience different kinds of problems. Please help us by reporting such problems to us. We will try to fix them as soon as possible.

Information on using the new simulation engine is avaible here.

Last modified: Thu Jan 12 12:47:54 2006 -- Design/CPN Online admin