The INTPOINT Procedure
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Overview
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Getting Started
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SyntaxFunctional SummaryDictionary of OptionsPROC INTPOINT StatementCAPACITY StatementCOEF StatementCOLUMN StatementCOST StatementDEMAND StatementHEADNODE StatementID StatementLO StatementNAME StatementNODE StatementQUIT StatementRHS StatementROW StatementRUN StatementSUPDEM StatementSUPPLY StatementTAILNODE StatementTYPE StatementVAR Statement
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DetailsInput Data SetsOutput Data SetsConverting Any PROC INTPOINT Format to an MPS-Format SAS Data SetCase SensitivityLoop ArcsMultiple ArcsFlow and Value BoundsTightening Bounds and Side ConstraintsReasons for InfeasibilityMissing S Supply and Missing D Demand ValuesBalancing Total Supply and Total DemandHow to Make the Data Read of PROC INTPOINT More EfficientStopping Criteria
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ExamplesProduction, Inventory, Distribution ProblemAltering Arc DataAdding Side ConstraintsUsing Constraints and More Alteration to Arc DataNonarc Variables in the Side ConstraintsSolving an LP Problem with Data in MPS FormatConverting to an MPS-Format SAS Data SetMigration to OPTMODEL: Production, Inventory, Distribution
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The INTPOINT procedure solves the Network Program with Side Constraints (NPSC) problem (defined in the section Mathematical Description of NPSC) and the more general Linear Programming (LP) problem (defined in the section Mathematical Description of LP). NPSC and LP models can be used to describe a wide variety of real-world applications ranging from production, inventory, and distribution problems to financial applications.
Whether your problem is NPSC or LP, PROC INTPOINT uses the same optimization algorithm, the interior point algorithm. This algorithm is outlined in the section The Interior Point Algorithm.
While many of your problems may best be formulated as LP problems, there may be other instances when your problems are better formulated as NPSC problems. The section Network Models describes typical models that have a network component and suggests reasons why NPSC may be preferable to LP. The section NPSC Problems outlines how you supply data of any NPSC problem to PROC INTPOINT and call the procedure. After it reads the NPSC data, PROC INTPOINT converts the problem into an equivalent LP problem, performs interior point optimization, then converts the solution it finds back into a form you can use as the optimum to the original NPSC model.
If your model is an LP problem, the way you supply the data to PROC INTPOINT and run the procedure is described in the section LP Problems.
You can also solve LP problems by using the OPTLP procedure. The OPTLP procedure requires a linear program to be specified by using a SAS data set that adheres to the MPS format, a widely accepted format in the optimization community. You can use the MPSOUT= option in the INTPOINT procedure to convert typical PROC INTPOINT format data sets into MPS-format SAS data sets.
The remainder of this chapter is organized as follows:
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The section Typical PROC INTPOINT Run describes how to use this procedure.
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The section Syntax: INTPOINT Procedure describes all the statements and options of PROC INTPOINT.
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The section Functional Summary lists the statements and options that can be used to control PROC INTPOINT. The Dictionary of Options is helpful to find information on a particular option.
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The section Details: INTPOINT Procedure contains detailed explanations, descriptions, and advice on the use and behavior of the procedure.
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PROC INTPOINT is demonstrated by solving several examples in the section Examples: INTPOINT Procedure.