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SENSITIVITY ANALYSIS: COMPUTER SOLUTION  97



                                3.3     Sensitivity Analysis: Computer Solution


                                      In Section 2.4 we showed how computer packages can be used to solve the GulfGolf
                                      linear programme. Let us demonstrate the use of The Management Scientist in
                                      performing sensitivity analysis by considering the solution to the GulfGolf linear
                                      programme shown in Figure 3.4.

                                      Interpretation of Computer Output
                                      In Appendix 2.2 we discussed the Management Scientist output in the top portion of
                                      Figure 3.4. So, after rounding, we see that the optimal solution is S ¼ 540 standard
                                      bags and D ¼ 252 deluxe bags; the value of the optimal solution is $7668. The
                                      Reduced Costs indicate how much the objective function coefficient of each decision
                                      variable would have to improve before that variable could assume a positive value in
                                      the optimal solution. For the GulfGolf problem, both variables already have positive
                                      values, and so their corresponding reduced costs are zero. In Section 3.4 we will
                                      interpret the reduced cost for a decision variable that does not have a positive value
                                      in the optimal solution.
                                         Immediately following the optimal S and D values and the reduced cost informa-
                                      tion, the computer output provides information about the constraints. Recall that
                                      the problem had four less-than-or-equal-to constraints corresponding to the hours


                                      Figure 3.4 The Management Scientist Solution for the GulfGolf Problem
                                        Objective Function Value =   7667.99463

                                              Variable                Value              Reduced Costs
                                           --------------       ---------------        -----------------
                                                  S                    539.99841                  0.00000
                                                  D                    252.00113                  0.00000

                                             Constraint          Slack/Surplus            Dual Prices
                                           --------------       ---------------        -----------------
                                                  1                      0.00000                  4.37496
                                                  2                    120.00070                  0.00000
                                                  3                      0.00000                  6.93753
                                                  4                     17.99988                  0.00000
                       EXCEL file
                                        OBJECTIVE COEFFICIENT RANGES
                           GulfGolf
                                          Variable       Lower Limit       Current Value       Upper Limit
                                       ------------  ---------------      --------------- ---------------
                                              S                 6.30000           10.00000           13.49993
                                              D                 6.66670            9.00000           14.28572

                                        RIGHT HAND SIDE RANGES
                                         Constraint      Lower Limit       Current Value       Upper Limit
                                        ------------ ---------------  --------------- ---------------
                                              1                495.59998         630.00000         682.36316
                                              2                479.99930         600.00000    No Upper Limit
                                              3                580.00146         708.00000         900.00000
                                              4                117.00012         135.00000    No Upper Limit







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