Using a starting-point heuristic

Describes impact of starting-point heuristics on performance of the barrier algorithm.

CPLEX supports several different heuristics to compute the starting point for the CPLEX barrier optimizer. The starting-point heuristic is specified by the BarStartAlg parameter, and Table 1 summarizes the possible settings and their meanings.

Table 1. 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 barrier starting point algorithm parameter IloCplex::BarStartAlg or CPX_PARAM_BARSTARTALG.