Using a Starting-Point Heuristic

ILOG CPLEX 11.0 User's Manual > Continuous Optimization > Solving LPs: Barrier Optimizer > Tuning Barrier Optimizer Performance > Using a Starting-Point Heuristic

Using a Starting-Point Heuristic

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ILOG CPLEX supports several different heuristics to compute the starting point for the ILOG CPLEX Barrier Optimizer. The starting-point heuristic is specified by the BarStartAlg parameter, and Table 10.8 summarizes the possible settings and their meanings.

Table 10.8 BarStartAlg Parameter Settings for Starting-Point Heuristics

Setting	Heuristic
`1`	dual is 0 (default)
`2`	estimate dual
`3`	average primal estimate, dual 0
`4`	average primal estimate, estimate dual

For most problems the default works well. However, if you are using the dual preprocessing option (setting the parameter PreDual to 1) then one of the other heuristics for computing a starting point may perform better than the default.

In the Interactive Optimizer, use the command set barrier startalg i, substituting a value for i.
When using the Component Libraries, set the parameter IloCplex::BarStartAlg or CPX_PARAM_BARSTARTALG.

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