doubly logarithmic tree

{{Short description|Concept in computer science}}

In computer science, a doubly logarithmic tree is a tree where each internal node of height 1, the tree layer above the leaves, has two children, and each internal node of height h > 1 has 2^{2^{h-2}} children. Each child of the root contains \sqrt{n} leaves.{{citation|first1=Omer|last1=Berkman|first2=Baruch|last2=Schieber|author2-link=Baruch Schieber|first3=Uzi|last3=Vishkin|author3-link=Uzi Vishkin|title=Optimal doubly logarithmic parallel algorithms based on finding all nearest smaller values|journal=Journal of Algorithms|volume=14|pages=344–370|year=1993|issue=3|doi=10.1006/jagm.1993.1018|citeseerx=10.1.1.55.5669}} The number of children at a node from each leaf to root is 0,2,2,4,16, 256, 65536, ... {{OEIS|id=A001146}}

File:Double log tree.png

A similar tree called a k-merger is used in Prokop et al.'s cache oblivious Funnelsort to merge elements.Harald Prokop. [http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.44.5650 Cache-Oblivious Algorithms]. Masters thesis, MIT. 1999.

References

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Further reading

  • M. Frigo, C.E. Leiserson, H. Prokop, and S. Ramachandran. Cache-oblivious algorithms. In Proceedings of the 40th IEEE Symposium on Foundations of Computer Science (FOCS 99), p. 285-297. 1999. [https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=814600 Extended abstract at IEEE], [http://citeseer.ist.psu.edu/307799.html at Citeseer].
  • Demaine, Erik. [http://courses.csail.mit.edu/6.897/spring03/scribe_notes/L17/lecture17.pdf Review of the Cache-Oblivious Sorting]. Notes for MIT Computer Science 6.897: Advanced Data Structures.

Category:Trees (data structures)