245Efciency and Variance Reduction
An obvious one is the capabilities of the computer used to do the calculations.
Both the speed and number of processors available are important deter-
minants. If the software can utilize multiple cores (e.g., in the computer or
in the cloud) and the model can run in parallel across various processors
(Fujimoto etal. 2010; Taylor etal. 2011), then the execution time can be cut
down substantially.
The next obvious factor is the number of calculations required by the model.
The volume of computations in a replication depends on the numberof enti-
ties simulated, how often their experience is updated, and the number of
events and the complexity of the logic that needs to be processed. The more
transactions the ...