Star
Description
The Star algorithm is applicable to communication operations (such as Broadcast, Reduce, Gather, and Scatter) with a root rank. The communication operations are completed in one step using the star or full-mesh topology. The following figure shows the implementation of the Star algorithm using the Broadcast operator as an example. The root rank collects data from other ranks using the star topology.
Required Time Calculation
If the size of the communication data between each non-root rank and the root rank is n, the time required for the communication of the entire Star algorithm is 
.
Parent topic: Collective Communication Algorithms