Changes to the log
In CPLEX V12.10.0, additional information has been added to the CPLEX log.
Display algorithms in concurrent optimizer
When solving an LP with the concurrent optimizer (for a MIP with the option MIP node log display information,
CPXPARAM_MIP_Display, greater or equal to 4), the different algorithms launched
will be displayed together with the number of threads they use. For example, when calling the
concurrent optimizer with 13 threads, the log should display at the beginning of the optimization as
follows:
Parallel mode: deterministic, using up to 13 threads for concurrent optimization:
* Starting dual Simplex on 1 thread...
* Starting Barrier on 11 threads...
* Starting primal Simplex on 1 thread...Display MIP restarts in dynamic search
As part of dynamic search, the MIP optimizer might perform a restart after having explored a certain number of nodes. In a MIP restart, the root node will be solved again and a new tree search started. The moments when restarts are performed are determined heuristically in an online fashion and depend on the convergence of the algorithm. With CPLEX 12.10.0, those restarts are clearly indicated in the logs with the following lines:
Performing restart 1
Repeating presolve.