The algorithms described in section 4 of the PhD have been implemented as a prototype in smalltalk and is available here for study or experimentation. This document describes how the files and how to use then.

The prototype has been developed and tested under IBM VisualAge 4.02 on windows NT. The interface to the package uses the Transcript of the development environment. To run the prototype you need a Smalltalk development environment. There are two different ways for downloading.

With Visualage Professional the two applications ZwkExtensions and ZwkPetri may be loaded from a ENVY-library as follows:

• Download the ENVY-library managerPetri.dat (470 KB) or unpack it with Winzip from managerPetri.ZIP (160 KB).
• In the Application Manager select Applications ® Import ® Applications...
• A file prompter appears. Select the downloaded library managerPetri.dat
• A prompter to select applications appear select both ZwkExtensions and ZwkPetri and push ok
• Look at the instructions in your System Transcript

If you do not use the ENVY-library or simply want to read the source then

• Download the source of the application ZwkPetri from fileoutZwkPetri.st (140 KB). If necessary download also the application ZwkExtensions from fileoutZwkExtensions.st(67 KB) which contains used extensions of Smalltalk base classes.

• Use an editor to read these files or read them into your smalltalk system by the filein function (first ZwkExtensions).

Finally, there are example nets in TPN format taken from CodeSign [Ess97]. Use either the winzip-archive tpnNets.ZIP(28 KB) or select some examples from the directory tpnNets.

The interface to the package uses the Transcript of the development environment. There is an interface classed called Petri. If the application ZwkPetri or if you execute (the class method) Petri help short instructions together with some code examples are printed to the Transcript. Simply mark a line of these instruction and execute it (ctrl e) to run the test. A simple scenario:

The class Petri implements a singleton pattern. The class holds an instance Petri singleton. Every message that the class does not understand is forwarded to the singleton instance, hence Petri printDetails and Petri singleton printDetails are equivalent. An instance of Petri contains a collection (members) of members that contain a net and different stages of analysis. The method reset initialises the instance, especially it empties members. With cutToFirst all but the first members are removed and more generally cutTo: n removes all but the n first members.

printStats prints one statistic line and printDetails the full information for each current member on the Transcript. The current member is by default the last one, however, the message all changes the current members to the set of all members and last changes it back to the last member.

To start a Petri net is needed. They may be produced by the methods starting with add... E.g. addNetEdwm creates the example spare part ordering net and with addNetEdwm: different sizes of this net may be created. addNetFromPtn asks for a file name that must contain a net description in PTN-format (examples in the directory tpnNets as described above).

To do apply an analysis the by the methods starting with to... are used. The are searching for the last member that contains a net or the analysis of a net in the necessary state, if none is found they do some default analysis to obtain such a net. Then the analysis is performed and added as last member, possibly after adding intermediate results.

The following tables lists sections of the PhD and which instance method of Petri fires an example of the algorithm described there. The middle column tries to identify a method that represents the core of the algorithm.