Using parallel optimizers in the Interactive Optimizer

Describes parallel optimization in the Interactive Optimizer.

For the mixed integer programming (MIP) optimizers of discrete models, the barrier optimizer for continuous models, and the concurrent optimizers for continuous models, the following sequence of commands invokes parallel deterministic optimization at default settings.

1. Start the parallel CPLEX Interactive Optimizer with the command cplex at the operating system prompt.
2. Enter your problem object, and populate it with data as usual.
3. Call the parallel optimizer with the optimize command. The optimizer then uses the maximum number of available threads in deterministic mode.

Linear programming models (LPs) are solved by default with the dual simplex algorithm. The dual simplex algorithm does not use multiple threads. In order to benefit from parallel execution for LP, you need to invoke the barrier or concurrent optimizers explicitly.

To abandon determinism by means of the parallel mode parameter

1. Start the parallel CPLEX Interactive Optimizer with the command cplex at the operating system prompt.
2. Enter the command: set parallel -1. The optimizer then uses the maximum number of available threads in opportunistic mode.
3. Enter your problem object and populate it with data as usual.
4. Optimize.