Performance Random Number Seed

Units:	-
Default Value:	0
Validation Rule:	Between 0 And 2000000000
Description:	Random number seed for the solver

Performance Random Number Seed (RNS) is passed through to the solver. The choice of solver seed modifies the solution path explored by the solver. This 'path' includes the order in which branch and bound nodes are explored during the solution of a MIP problem. This parameter is therefore unrelated to the Model Random Number Seed which govers PLEXOS variable realizations, outage patterns and similar.

Variations in solver seed can change the solution generated for both linear and mixed integer problems. In general, runtime and memory consumption will also change through variation of this parameter.

The sensitivity of a problem to the seeded search ordering is also known as Performance Variability.

• 'Good' problems with low performance variability should return very similar results, runtimes, and memory consumption etc. through variation of this parameter.
• 'Bad' problems with high performance variability may experience significant differences in runtime, memory and the solution itself through variation of this parameter.
• Inconsistency in runtime, memory consumption, and/or solutions generated between machines and/or runs may indicate high performance variability.

Alternative perspective: if build decisions change considerable through variation of this parameter, there may be no clear winner in terms of an expansion solution. There may exist a family solutions with very similar objective function values.