The LP Procedure
- Overview
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Getting Started
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Syntax
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DetailsMissing ValuesDense Data Input FormatSparse Data Input FormatConverting Any PROC LP Format to an MPS-Format SAS Data SetConverting Standard MPS Format to Sparse FormatThe Reduced Costs, Dual Activities, and Current TableauMacro Variable _ORLP_PricingScalingPreprocessingInteger ProgrammingSensitivity AnalysisRange AnalysisParametric ProgrammingInteractive FacilitiesMemory ManagementOutput Data SetsInput Data SetsDisplayed OutputODS Table and Variable NamesMemory Limit
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ExamplesAn Oil Blending ProblemA Sparse View of the Oil Blending ProblemSensitivity Analysis: Changes in Objective CoefficientsAdditional Sensitivity AnalysisPrice Parametric Programming for the Oil Blending ProblemSpecial Ordered Sets and the Oil Blending ProblemGoal-Programming a Product Mix ProblemA Simple Integer ProgramAn Infeasible ProblemRestarting an Integer ProgramAlternative Search of the Branch-and-Bound TreeAn Assignment ProblemA Scheduling ProblemA Multicommodity Transshipment Problem with Fixed ChargesConverting to an MPS-Format SAS Data SetMigration to OPTMODEL: AssignmentMigration to OPTMODEL: Multicommodity Transshipment
- References
The system option MEMSIZE sets a limit on the amount of memory used by the SAS System. If you do not specify a value for this option, then the SAS System sets a default memory limit. Your operating environment determines the actual size of the default memory limit, which is sufficient for many applications. However, to solve most realistic optimization problems, the LP procedure might require more memory. Increasing the memory limit can reduce the chance of an out-of-memory condition.
Note: The MEMSIZE system option is not available in some operating environments. See the documentation for your operating environment for more information.
You can specify -MEMSIZE 0 to indicate all available memory should be used, but this setting should be used with caution. In most operating environments, it is better to specify an adequate amount of memory than to specify -MEMSIZE 0. For example, if you are running PROC OPTLP to solve LP problems with only a few hundred thousand variables and constraints, -MEMSIZE 500M might be sufficient to allow the procedure to run without an out-of-memory condition. When problems have millions of variables, -MEMSIZE 1000M or higher might be needed. These are “rules of thumb”—problems with atypical structure, density, or other characteristics can increase the optimizer’s memory requirements.
The MEMSIZE option can be specified at system invocation, on the SAS command line, or in a configuration file. The syntax is described in the SAS Companion book for your operating system.
To report a procedure’s memory consumption, you can use the FULLSTIMER option. The syntax is described in the SAS Companion book for your operating system.