simulation languages

[tjark struif bontkes]

I am developing large models that simulate agricultural development at the
regional level, taking into account agro-ecological as well as socio-economic
aspects. I also attempt to include interactions between various farm types.
The simulation that I use since quite a few years is DYNAMO.
Although I regularly read that DYNAMO is a user unfriendly, archaic
simulation language, I still use it for my research but also for my teaching.
The version that I now use can deal with large models and produces better
graphs under Windows.
Recently I compared it with STELLA and two in the Netherlands developed on
Fortran based programming environments.
I realize that I am biased because of the fact that I am so familiar with
DYNAMO, but for my purposes I still prefer the language.
An important advantage to me of DYNAMO is its array capability, a feature
that is lacking in many other simulation packages.
However I am still looking for a simulation package that offers additional
possibilities:
1. I would like to be able to run a model with two or more different time
steps, to simulate e.g. the process of farm income on an annual basis and the
hydrological dynamics on a weekly basis.
2. Tools that facilitate sensitivity analyses.
3. Statistical tools

I would be very grateful to receive suggestions for packages that include on
or more of these features.

Tjark Struif Bontkes
Dept. of Ecological Agriculture
Wageningen Agricultural University
The Netherlands
E-mail: Tjark.Struifbontkes@users.eco.wau.nl

[saeed@ait.ac.th (Prof Khalid Sae]

for Tjark Struif Bontkes

You will probably end up with a stiff model if you try to combine weekly
and yearly dynamics, irrespective of the software or language you program
your problem in. A numerical soultion for this model through simulation
will offer many unsurmountable problems.

You might, alternatively, wish to consider taking yearly averages of weekly
quantities and modeling them as auxiliary relationships.

Best wishes,

Khalid


Khalid Saeed
Infrastructure Planning & Management
School of Civil Engineering
ASIAN INSTITUTE OF TECHNOLOGY
G.P.O. Box 2754, Bangkok, THAILAND
phones: (66-2)524-5681, (66-2)524-5785; fax: (66-2)524-5776
email saeed@ait.ac.th