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Instituto Politécnico NacionalEscuela Superior de Cómputo

M. en C. Eduardo Bustos Farías

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DESCARGA DEL PROGRAMAhttp://www.ubmail.ubalt.edu/~harsham/opre640c/partX.htm#rlpILPQSB

We will use WinQSB package as a computer-assisted learning tool to gain a good"hands-on" experience on concepts andtechniques used in this course. These labsexperimentation will enhance yourunderstanding of the technical conceptscovered in this course. The QSB isdeveloped and maintains by Yih-LongChang. This software package contains themost widely used problem-solvingalgorithms in Operations Research andManagement Science (OR/MS).

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WinQSB InstallationInstructions

1. Create a folder (directory) named WinQSB2. Open the CD-ROM files, and save this file to the folder

created in step 1. 3. Run the WinQSB.exe program first (You must execute

these programs in the proper sequence). Go to the file location (where you saved it step 2) and double click (orclick on file-open) to execute the file. Follow the promptsand extract the files to the WinQSB folder that youcreated in step 1.

4. Run the WinQSB.exe program. Go to the file location(where you saved it in step 2) and double click (or clickon file-open) to execute the file. Follow the prompts andextract the files to the WinQSB folder that you created in step 1.

5. Reboot your system. 6. You will now have a list of files (both executable and

support files) in the WinQSB folder that you created in step 1. To use the Linear Program model, for example, click (or double click) on the file called LP ILP exe

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ComputerImplementations with the

WinQSB Package• Use the LP/ILP module in your WinQSB package for two

purposes: to solve large problems, and to performnumerical experimentation for understanding concepts wehave covered in the LP and ILP sections. Variable Type:Select the variable type from the "Problem Specification" screen (the first screen you see when introducing a newproblem); for linear programming use the default"Continuous" option.

• Input Data Format: Select the input data format fromthe "Problem Specification" screen. Usually, it is preferredto use the Matrix format to input the data. In the Normal format the model appears typed in. This format may be found more convenient when solving a large problem withmany variables. You can go back and forth between theformats, selecting the "Switch to the…" from the Format menu.

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• Variable/Constraint Identification: It is a good idea to renamevariables and constraints to help identify the context theyrepresent. Changing the names of variables and constraints isdone in the Edit menu.

• Best Fit: Using the best fit from the Format menu lets eachcolumn have its own width.

• Solving for the Optimal Solution (if it exists): Select Solvethe problem from the Solve and analyze menu, or use the "solve" icon at the top of the screen. The run returns a "CombinedReport" that gives the solution and additional output results(reduced costs, ranges of optimality, slack/surplus, ranges offeasibility, and shadow prices).

• Solving by the Graphic Method: Select the Graphic methodfrom the Solve and Analyze menu (can only be used for a two-variable problem.) You can also click the graph icon at the top thescreen. You can re-scale the X-Y ranges after the problem has been solved and the graph is shown. Choose the Option menu andselect the new ranges from the drop down list.

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Alternate Optimal Solutions (ifthey exist): After solving theproblem, if you are notified that"Alternate solution exists!!", you can see all the extreme point optimalsolutions by choosing the Resultsmenu and then select Obtainalternate optimal. Also visit MultipleSolutions section on this Web site forsome warnings.

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