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
| Iteration Log for the Network Simplex Solver |
After finding the embedded network and formulating the appropriate relaxation, the network simplex solver uses a primal network simplex algorithm. In the case of a connected network, with one (weakly connected) component, the log will show the progress of the simplex algorithm. The following information is displayed in the iteration log:
- Iteration
indicates the iteration number.
- PrimalObj
indicates the primal objective value of the current solution.
- Primal Infeas
indicates the maximum primal infeasibility of the current solution.
- Time
indicates the time spent on the current component by network simplex.
The frequency of the simplex iteration log is controlled by the PRINTFREQ= option. The default value of the PRINTFREQ= option is 10,000.
If the network relaxation is disconnected, the information in the iteration log shows progress at the component level. The following information is displayed in the iteration log:
- Component
indicates the component number being processed.
- Nodes
indicates the number of nodes in this component.
- Arcs
indicates the number of arcs in this component.
- Iterations
indicates the number of simplex iterations needed to solve this component.
- Time
indicates the time spent so far in network simplex.
The frequency of the component iteration log is controlled by the PRINTFREQ= option. In this case, the default value of the PRINTFREQ= option is determined by the size of the network.
The PRINTLEVEL2= option adjusts the amount of detail shown. By default, PRINTLEVEL2=MODERATE and reports as in the preceding description. If PRINTLEVEL2=NONE, no information is shown. If PRINTLEVEL2=BASIC, the only information shown is a summary of the network relaxation and the time spent solving the relaxation. If PRINTLEVEL2=AGGRESSIVE, in the case of one component, the log displays as in the preceding description; in the case of multiple components, for each component, a separate simplex iteration log is displayed.