The Linear Programming Solver
- Overview
- Getting Started
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Syntax
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Details
Presolve Pricing Strategies for the Primal and Dual Simplex Solvers The Network Simplex Algorithm The Interior Point Algorithm Macro Variable OROPTMODEL Iteration Log for the Primal and Dual Simplex Solvers Iteration Log for the Network Simplex Solver Iteration Log for the Interior Point Solver Problem Statistics Data Magnitude and Variable Bounds Variable and Constraint Status Irreducible Infeasible Set
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Examples
Diet Problem Reoptimizing the Diet Problem Using BASIS=WARMSTART Two-Person Zero-Sum Game Finding an Irreducible Infeasible Set Using the Network Simplex Solver Migration to OPTMODEL: Generalized Networks Migration to OPTMODEL: Maximum Flow Migration to OPTMODEL: Production, Inventory, Distribution Migration to OPTMODEL: Shortest Path
- References
| Variable and Constraint Status |
Upon termination of the LP solver, the .status suffix of each decision variable and constraint stores information about the status of that variable or constraint. For more information about suffixes in the OPTMODEL procedure, see the section Suffixes.
Variable Status
The .status suffix of a decision variable specifies the status of that decision variable. The suffix can take one of the following values:
- B
basic variable
- L
nonbasic variable at its lower bound
- U
nonbasic variable at its upper bound
- F
free variable
- I
LP model infeasible (all decision variables have .status equal to I)
For the interior point solver with IIS= OFF, .status is blank.
The following values can appear only if IIS= ON. See the section Irreducible Infeasible Set for details.
- I_L
the lower bound of the variable is violated
- I_U
the upper bound of the variable is violated
- I_F
the fixed bound of the variable is violated
Constraint Status
The .status suffix of a constraint specifies the status of the slack variable for that constraint. The suffix can take one of the following values:
- B
basic variable
- L
nonbasic variable at its lower bound
- U
nonbasic variable at its upper bound
- F
free variable
- I
LP model infeasible (all decision variables have .status equal to I)
The following values can appear only if option IIS= ON. See the section Irreducible Infeasible Set for details.
- I_L
the "GE" (
) condition of the constraint is violated - I_U
the "LE" (
) condition of the constraint is violated - I_F
the "EQ" (
) condition of the constraint is violated