1. Program purpose.
2. Installation.
3. References.

1 Program purpose

The ECF (Economic Circular Flows) program allows users to build their own economic models in an interactive manner. Nodes and flows are added by mouse clicks and connected to one another by dragging connector symbols. The magnitude of some flows have to be prescribed, while the other flows are calculated.

This issue of the program is version 2.9.7.4. Some pictures in this manual may not show the latest program version but the functions are the same. The latest features of the current version are not documented at all (sorry).

The version 2.8.5.1 can:

1. Draw diagrams of sectors, junctions, sources/sinks and flow paths.
2. Define a time axis.
3. Use a standard set of units.
4. Prescribe flow rate as function of time for flows.
5. Calculate flow balances for nodes.
6. Show static scenarios for different times (years) along a time axis.
7. Save and open models.
8. Print diagrams to a printer.
9. Export flow data and equation system to a text, Excel, Matlab or Maple file.
10. Import data via copy and paste.
11. Use flow splitters with time dependent coefficients.
12. Define price relations between money and commodity flows.  
13. Make submodels inside sectors.  
14. Make processes.
15. Define flows for sources/sinks. New!
16. Has improved features, errors have been corrected.

Future versions will have more features until the whole theory of static and dynamic models is covered. See contents parts 1 and 2. Some mayor improvements will be:

1. Enhanced plots of system diagrams and flow time histories. 
2. Dialogs for adding descriptions to model, nodes and flows.
3. Analysis variables, shows sums etc of  flows, e.g. GDP.
4. Text reports describing the whole model and its components.
5. Adding integrators such as production resources and stocks. See Part 2, Chapter 4, A simple production system. Dynamic simulation will be possible. Financial accounts for savings and loans will give even more possibilities, see Part 1, Chapter 11, Financial sector, interests.
6. The real interesting thing comes with the introduction of non-linear components. I think that the most common non-linearities are limits on state variables such as stocks>=0, production capacity<=max, bank accounts>=0 and so on. Non-linearities will possibly give double cycles, triple cycles or chaotic behavior.

Anyone who is interested is invited to contribute to the development.

2 Installation

Java Plug-in and ECF program

The easiest way of running the ECF program is to first install a Java Plug-in. Java Plug-in allows you to run any executable jar-file by a double mouse click. (If you already have a Java plug-in on your system, then you do not have to do this once more.) The start page http://java.com/en/index.jsp will lead you to automatic download if you press the Free Download button. 

Then download the ECF executable jar-file by clicking this link ECF.jar . Save the file on your computer. Newer Windows versions (Windows 2000) change the name to ECF.zip. Change it back to ECF.jar.  Then just double click on the file and it starts directly. You can also download sample models  ECFModels.zip  and unzip to a model directory.

Developers can find the Java Runtime Environment and ECF source code here.

3 References

The theory of Economic Circular Flows (ECF) is described on www.ecf-theory.se.

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