PrimeRoute uses either a heuristic algorithm or a global algorithm to determine the best jobs to dispatch to the best TTs. PR-TT uses the global algorithm by default. However, PR-TT uses the heuristic algorithm if any of the following are true:
The pool is a dedicated vessel or rail pool.
There are non-uniform truck capabilities in an equipment pool.
Examples of non-uniform truck capabilities are when some trucks in the final TT list are not capable of handling some paired jobs or when the Allowed Chassis Type for one or more trucks in a pool are set to a value other than ANY, such as CASSETTESONLY, CHASSISONLY, or BOMBCARTSANDCHASSIS.
Global optimization is taking too long and is therefore aborted (with current computing power, the possibility of this happening is very low).
If the pool is dedicated to only one vessel or rail POW, then the heuristic and global algorithms generate the same results. Therefore, PR-TT uses the heuristic algorithm, since it is faster and saves time.
PR-TT also uses the heuristic algorithm when the trucks in the pool are not uniform. Non-uniform trucks that cannot handle all paired jobs result in complicated pairing decisions that cannot be solved within a reasonable amount of time using the global algorithm. In this case, PR-TT also uses the heuristic algorithm to save time.
The heuristic algorithm looks for the lowest cost CHE for the first job, then the lowest cost CHE for the second job, and so on. However, the global algorithm considers the lowest total cost of all jobs for all CHEs in the pool.
The above illustration is an example of two trucks being considered for two jobs. For this example, PrimeRoute dispatches the jobs for each type of algorithm as follows:
Heuristic: PrimeRoute looks for the lowest cost truck for job 1 and then the lowest cost truck for job 2. In this case, the lowest cost truck for job 1 is T1, with a cost of 10. Therefore, PrimeRoute dispatches job 1 to T1. Now, the only job left is job 2, so PrimeRoute dispatches job 2 to T2.
Global: PrimeRoute looks at the total lowest cost for all jobs for all trucks. In this case, if T1 does job 1 and T2 does job 2, the total cost is 45. However, if T1 does job 2 and T2 does job 1, the total cost is 40. Therefore, PrimeRoute dispatches job 1 to T2 and job 2 to T1 for the lowest total cost of 40, which is the overall optimal solution.