Parallel Program Design

This program calculates the effect of pollution on tree growth and mortality for a geographic area.

• SPMD
  • Each process will run the same program.
• Domain
  • Irregular geometry, dynamic

    The domain is irregular because it is broken up by the lake and the city (no trees). It is dynamic because the computation shifts with time. Initially, only trees near the pollution source may be affected, so may require more computation. By the end of the simulation, these trees may have died (now requiring no computation) and trees far from the source may be showing long-term effects.

  • Non-homogeneous members

    Different tree species may be affected in different ways, and thus require different amounts of computation.

  • No interaction between members (trees)
• Technique: 1-D block-cyclic decomposition
  • The diagram shows cyclic decomposition, where each process is dealt slices of data in round-robin fashion. The areas of no work (lake and city) are now divided between multiple processes. As computation requirements shift with time, the load should remain balanced. This model works well for this program because there is no communication pattern based on location of members.