4 research outputs found
Theory and applications of hashing: report from Dagstuhl Seminar 17181
This report documents the program and the topics discussed of the 4-day Dagstuhl Seminar 17181 âTheory and Applications of Hashingâ, which took place May 1â5, 2017. Four long and eighteen short talks covered a wide and diverse range of topics within the theme of the workshop. The program left sufficient space for informal discussions among the 40 participants
Load thresholds for cuckoo hashing with overlapping blocks
Dietzfelbinger and Weidling [DW07] proposed a natural variation of cuckoo
hashing where each of objects is assigned intervals of size
in a linear (or cyclic) hash table of size and both start points are chosen
independently and uniformly at random. Each object must be placed into a table
cell within its intervals, but each cell can only hold one object. Experiments
suggested that this scheme outperforms the variant with blocks in which
intervals are aligned at multiples of . In particular, the load threshold
is higher, i.e. the load that can be achieved with high probability. For
instance, Lehman and Panigrahy [LP09] empirically observed the threshold for
to be around as compared to roughly using blocks.
They managed to pin down the asymptotics of the thresholds for large ,
but the precise values resisted rigorous analysis.
We establish a method to determine these load thresholds for all , and, in fact, for general . For instance, for we
get . The key tool we employ is an insightful and general
theorem due to Leconte, Lelarge, and Massouli\'e [LLM13], which adapts methods
from statistical physics to the world of hypergraph orientability. In effect,
the orientability thresholds for our graph families are determined by belief
propagation equations for certain graph limits. As a side note we provide
experimental evidence suggesting that placements can be constructed in linear
time with loads close to the threshold using an adapted version of an algorithm
by Khosla [Kho13]
Theory and Applications of Hashing (Dagstuhl Seminar 17181)
This report documents the program and the topics discussed of the 4-day
Dagstuhl Seminar 17181 "Theory and Applications of Hashing",
which took place May 1-5, 2017. Four long and eighteen short talks
covered a wide and diverse range of topics within the theme of the workshop.
The program left sufficient space for informal discussions among the 40 participants