| Ø | Click on the Setup a Simulation button. |
| Ø | Click on Reference Demand, type in the value 0 (zero) and press Enter. |
| Ø | Click on the Simulate button. |
You should get the error message
| Ø | Click on OK. |
There will be an error window that appears.
This window tells you what variable was being computed at what time when the problem was detected. Because the error occurred at time 0, it is only practical to trace it using the Table tool.
| Ø | Click on target price in the error window to select it into the workbench. |
If you are using Vensim PLE or PLE Plus:
| Ø | Click on the Table tool. |
| Ø | Click on the Causes Tree tool. |
| Ø | Click on expected demand in the Causes tree output. |
| Ø | Click on the Table tool. |
| Ø | Click on target revenue in the Causes tree output. |
| Ø | Click on the Table tool. |
or if you are Using Vensim Standard, Runtime, Professional or DSS
| Ø | Right click on the Table tool. |
| Ø | Under Show Link click on Cause and click on OK. |
| Ø | Click on the Table tool. |
then
You will see output that looks something like:
Next to target price you will see the value "--." This indicates that target price was never successfully computed. Both expected demand and target revenue were computed and their values are shown. Since the equation for target price is:
target price=target revenue/expected demand
It is clear why there is an error - division by 0. To determine why expected demand is 0 we can continue to trace causes. You should be able to demonstrate quite quickly that expected demand is 0 because demand is 0 because reference demand is 0.
We can fix the equation for target price so that it will not cause and error even when expected demand is 0. This is done in "Model Revisions"below.
