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Operations Research Models and Methods / Methods / Network Methods /
Teach Transportation Add-in


Select a Cell to Enter the Basis


Choosing the Entering Cell

When there are some cells with negative reduced cost, any one of these cells may be chosen to enter the basis. The image shows the dialog the add-in produces in the Instruction Mode. Two fields are presented for the row and column of the entering cell.

In the instruction mode a Hint button is also provided. Clicking on the hint button once, causes the cells with negative reduced costs to be colored yellow. Clicking on it twice selects the cell with the most negative reduced cost. Clicking it further will cause the selection to be cycled through all the cells with negative reduced cost. Any of these can be chosen by clicking on the OK button in the dialog.

Hints about the Entering Cell

This image shows the dialog after two clicks of the hint button. The cell with the most negative reduced cost is chosen. Clicking the OK button presents the next step of the algorithm.

The operating options effect what information shown at each iteration. In the demonstration option, the student is not asked to choose the entering cell. A program selects the most negative and displays a dialog with that information. In the Self option, no hints are provided and it is possible to choose any cell to enter. In the Run option, no dialogs are presented, but the program quickly runs through iterations, pausing for the delay entered in the original problem definition dialog.

The option buttons appear in each dialog, so the student can switch between options. Once a cell is chosen to enter the basis, the next step is to find a cell to leave the basis.

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Operations Research Models and Methods
by Paul A. Jensen and Jon Bard, University of Texas, Copyright by the Authors