Menu | <<<< | >>>> | Solve a model with controls on the {Model} sheet of the model workbook

All of the controls for generating model solutions are found on the {Model} sheet of every VORSIM-built model. After the solver has been installed, the configuration buttons have been removed as shown above. The [Solve Base] button solves the model for the base time period. This is useful for checking if equations are valid in Excel and if the model has a feasible solution. If this step ends with a message saying there is no feasible solution, you may need to examine your model structure and variables before attempting a full solution (it is possible that your model will solve properly in spite of this message under some circumstances).

The [Solve DEMO model] button (DEMO is the model shown in this example) is clicked when you want to solve the model for all time periods using exogenous data from the <DEMOexog.xls> exogenous data workbook. Alternative solutions can be generated by changing exogenous data with the [Change Exogenous Variable | View Solution Variable] button. With this procedure, you change one exogenous variable at a time.

In VORSIM 15 there is a second option for changing exogenous data in a time series model. The [a. Load time series exogenous data workbook (****exot.xls) for exogenous data entry] button brings up a time series based workbook where all exogenous data for one sheet (here E, WR) are together so that you can manually change many exogenous variables in one sitting. When you are done changing variables in the workbook, switch back to the model sheet and click the [b. Return exogenous data entered manually in the ****exot.xls workbook to the ****exog.xls exogenous data workbook for model] button to prepare the model for solution. Then the model can be solved with the [Solve Base] or [Solve **** model] buttons.

There is one more button [View Eq.]. With the cursor on a yellow cell containing an equation, this button produces a brief description of the equation in terms of variable names.