The OPTLP Procedure
- Overview
- Getting Started
-
Syntax
-
DetailsData Input and OutputPresolvePricing Strategies for the Primal and Dual Simplex SolversWarm Start for the Primal and Dual Simplex SolversThe Network Simplex AlgorithmThe Interior Point AlgorithmIteration Log for the Primal and Dual Simplex SolversIteration Log for the Network Simplex SolverIteration Log for the Interior Point SolverIteration Log for the Crossover AlgorithmConcurrent LPODS TablesIrreducible Infeasible SetMacro Variable _OROPTLP_
-
Examples
- 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 shows 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 LOGFREQ= option. The default value of the LOGFREQ= 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 LOGFREQ= option. In this case, the default value of the LOGFREQ= option is determined by the size of the network.
The LOGLEVEL= option adjusts the amount of detail shown. By default, LOGLEVEL= is set to MODERATE and reports as described previously. If set to NONE, no information is shown. If set to BASIC, the only information shown is a summary of the network relaxation and the time spent solving the relaxation. If set to AGGRESSIVE, in the case of one component, the log displays as described previously; in the case of multiple components, for each component, a separate simplex iteration log is displayed.