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The project

The project goes back to 1995 and its evolutionary models were originally programmed in the language of Maple, a standard package designed for symbolic mathematics. The choice of Maple had not only advantages (a powerful language, a huge mathematical library, etc.) but also highly constraining disadvantages (slowness in numerical computation, dependence on the commercial Maple program, etc.). Therefore, the DRUIDIC models are being transferred to Lsd.

The family of evolutionary models implemented in Lsd

In contrast to the standard AK Nelson-Winter model, the AL models leaves out physical capital and concentrates on the basic production factors: knowledge, production labour that produce output by means of knowledge, and research labour (including parts of production activities) that improves the stock of knowledge. This design has sigificant consequences on how economic problems are considered: basically, they become problems of the division and coordination of labour (both productive and innovative). To explore systematically these problems is a huge task, and in this respect present AL models should be considered as a strategically chosen starting point. For instance, the simplest version of an AL model will be extended with an explicit treatment of the decisions of employees and households. Another priority is to incluse the emergence of a multisectoral economy with exchange of intermediate goods between multiactivity AL-like firms.

The Lsd implementation of the AL model family has several purposes:

1. The simulation models are designed to be a teaching and self-learning tool about evolutionary processes, e.g. by allowing a gradual extension of the complexity of the studied problems.
2. The simplicity and extendibility of the basic AL model suggest that it may function as a standard against which several types of research-oriented models can be compared; here the foundation of this basic AL model in the analytical results of pure replicator dynamics is of major importance.
3. The AL models are really a fairly large family of models that, at least in principle, can be easily extended to cover a wide range of topics (which e.g. have been discussed in several of Andersen's papers; see the references).
   • AL Mark 2: The present version includes individual employees and households, and this is just the beginning of a treatment of many issues relating to demand and to the labour market.
   • AL Mark 3a: Here the production and research of each firm covers not only final output but also intermediate goods and markets for intermediate goods can emerge, so we have a multisectoral AL model family with wide perspectives.
   • AL Mark 3b: Later there will be an extension to the production of an increasing range of goods for the household sector, as it has already been implemented in Maple.

Using and developing the DRUIDIC models

Information of these topics is found in several files that are distributed together with the AL simulation application. Most of these files have been integrated in a fairly extensive help and documentation system that can be inspected through a web browser. In the directory of each DRUIDIC model there is e.g. a description file, a file recording the changes (so that is it easy to see the new features of an update), an extensively commented Lsd equation file (fun_AL2.cpp), etc. A commented list of the contents of each directory is found in the readme.txt file.

It is obvious that the use of the DRUIDIC models presupposes an elementary knowledge about the Lsd system, which e.g. can be obtained in a couple of hours by means of the first two Lsd tutorials from the Help menu of the Lsd Model Manager. This might be sufficient to perform the premade exercises that are described in the tutorials file.