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Increasing Granularity

• Surface to volume effects

  Communication   surface of subdomain; computation   subdomain volume.

  Example: 2D Grid
  • "surface" scales with problem size,
  • "volume" scales with problem size squared.
  Communication/computation ratio decreases as task size increases.
• Replicating communication

  Trade off replicated computation for reduced communication.

  Example: replicated summation
• Avoiding Communication

  Agglomerate tasks that cannot execute concurrently.

(See Foster, Figures 2.13, 2.14, 2.15)