Menu | <<<< | >>>> | Additional options for model configuration

Three other options are available for configuring models. They can be used in addition to Options 1 and 2. The top picture shows the options.

[3. Option: Select (yellow) aggregate target cell (formula = 0 when model solved)] – This option allows you to pick an overall target cell to be driven to 0 in a solution. For example if you have 10 world markets to clear, you might create a variable which is the sum of those market variables, each of which must be 0 at equilibrium. This option may speed up the solution process in some cases and will make sure the solver continues working until all markets are really cleared. In the example above, the variable MCMe is an equation (yellow cell) calculating the sum of MCMqsBL, MCMqsNUT, MCMqsW; each of which must be 0 value at equilibrium. This option is generally not needed for very small models such as DEMO but it very useful for the complete solution of large models.

[Option: Apply LOWER & UPPER bounds on change (green) variables] – This option can be applied after options 1, 2 and 3. Constraints on some or all change variables can be imposed. Follow the menu directions when the button is clicked. For example, change variables normally centered on a value of 1 could be bounded below by 0.6 and above by 1.2. Variables used for the lower and upper bounds and must be available in your model for service in this manner. Bounds can prevent nonsense solutions and they can speed up solution convergence by limiting the exploration range for the Solver. They are especially helpful for the solution of large complex models. This procedure has been removed in VORSIM 15.

[Option: Select instrument (white) and formula (yellow) cells >=0] – This option lets you add a >=0 option for some variables in addition to the =0 option when you use options 1 and 2. This may be useful for some kinds of models where in addition to cleared markets for example, you might want to force some other variables to be >=0. This procedure has been removed in VORSIM 15.

INSTEAD of configuring a model for solution, in VORSIM 15 you can use a configuration that has been created earlier. This is very useful if you are rebuilding the model with different parameters or structure. Then you can simply click the button below and the model will be configured for solution.

[Option: USE A PREVIOUS CONFIGURATION] – If a configuration has been created (and therefore saved), it can be called up again with this button. A menu of available saved configurations comes up and you can choose from the list.