Hierarchical algorithms, approaches and data structures

This wiki page is intended to capture discussions around the "hierarchical" part of HiHAT. Initially, there's a focus on understanding usage requirements and surveying possible support.

• Hierarchical algorithms
  • Categories of Hierarchical Algorithms
• Requirements and Concerns
  • Overdecomposition can lead to excess overhead
  • The degree of decomposition needed may vary by target architecture, heterogeneity of the node's computing resources, NUMA-ness of the node, and topology of the network
  • Support representations of multi-D arrays, and make the movement of slices very efficient
• Approaches
  • Choose the degree of decomposition based on the target system and the input data set
  • Enable trade-offs between moving (halo) data and recomputing data
  • Decomposition could be done at successive levels of the hierarchy, where schedulers make choices at each level on whether and how to further decompose work and data
• Data structures
  • X10
  • OCR