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model

The figure shows the model sheet of the DEMO model workbook <DEMOmod.xls> after the model has been configured for solution. Buttons at the top of the sheet control model operations. The [QUIT] button closes the model and associated workbooks and returns you to the Solution Manager control screen. Yellow cells contain equations. Notice the model equation at the top, which is from the marked yellow cell (the equation for the variable EqpBL which has a base value of 1600). As the model is solved for each time period, new exogenous data is brought in and the solver drives the variables in the red cells to zero by changing the values in the green cells. In the case of the model DEMO, the green cells contain market prices, which drive sales minus production in the red cells to zero (e.g. clears the three product markets BL, NUT, and W). In summary, a full simultaneous equation model is a set of equations on the {Model} sheet of the model workbook. Such a sheet can be very large if the model is large. Model size is only limited by the maximum size of the Excel spreadsheet and the limit of about 100 target variables that can be changed by the Solver (a larger solver is available commercially that can handle more target variables). The following pages explain the sheets appearing in a model workbook.

In VORSIM 15, the model structure would be exactly the same as shown above, but the model name would be DEMOmod.xlsm.