Solving the Model

Computing the solution

Procedures for action

Thus far, you have entered all the identifiers, their attributes and their data. You will also need to build at least one procedure in order to be able to instruct AIMMS to take action. In this tutorial, you will enter two statements inside the body of the existing (empty) procedure MainExecution: one to solve the mathematical program, and the other to set the solution to zero when the mathematical program is not optimal.

The attribute form of ``MainExecution``

Fig. 27 The attribute form of MainExecution

Building a procedure

The procedure MainExecution can be completed as follows:

  • press the key to open the Model Explorer,

  • select the MainExecution procedure and open it by double-clicking ,

  • enter the two statements in the body attribute as illustrated in Fig. 27, or copy the below code

    solve LeastCostTransportPlan;

if ( LeastCostTransportPlan.ProgramStatus <> 'Optimal' ) then
        empty Transport, TotalTransportCost;
endif;

  • press the Check, Commit and Close button to register the changes.

Should AIMMS report errors, simply check your input and make the necessary corrections.

See also

More docs on .ProgramStatus, if, The EMPTY statement

Right-mouse for help

To obtain information about specific AIMMS keywords, you can use the right-mouse pop up menu to open the AIMMS documentation on the appropriate page with a single click. For instance, you can obtain help on the ProgramStatus keyword as follows:

  • position the cursor over the ProgramStatus keyword,

  • right-click the mouse and select the ProgramStatus entry in the Help submenu (see Fig. 28).

A right-mouse popup menu

Fig. 28 A right-mouse pop-up menu

See also

.ProgramStatus

Running the procedure

The procedure MainExecution is special in that there is a dedicated key, F6 , to execute this procedure. For all other procedures you can use the right mouse button to select the Run Procedure command.

Watching execution progress

By pressing the CTRL and P keys simultaneously, AIMMS displays a progress window with selected information on the progress it has made (or is making) during an execution phase. Fig. 29 shows the progress window you should expect to see.

The AIMMS progress window

Fig. 29 The AIMMS progress window

Results in data pages

You have already encountered data pages while entering the elements of sets and the numeric values of parameters. Once AIMMS has computed the values of the variable Transport, these values become immediately available on the corresponding data page. Just go to this variable in the model tree, and click on it. Then use the right mouse to select the Data… command to open the data page. This will open a pivot table with Transport data.

Data page displaying the solution for the variable `Transport`

Fig. 30 Data page displaying the solution for the variable Transport

Congrats!

You have computed and solved your first optimization model with AIMMS. Congrats !

You are now able to use the very basics of AIMMS software.

Continue to learn on the AIMMS Academy, and enroll to a more advanced course. This course will dig deeper in modeling using AIMMS, building a Web User Interface and communicating with an excel file or a database.

See you there ! 😁