Analyze if the Ruby hashing algorithm could be improved using Tabulation Hashing. This is a project for my Advanced Algorithms course by Alexandr Andoni at Columbia University.
The written C code for the project is in the tabulation_project branch of my fork of the Ruby project (MRI) in GitHub.
Ruby issue: https://bugs.ruby-lang.org/issues/16851
benchmark_tabulation.rb benchmarks the insertion of 600000 elements (by hashing their 64 bits ids) in an empty hash 100 times. Below are the times (in seconds) I got executing this code for different versions of the Ruby code:
- master (without Simple Tabulation): 29.68
- master with Linear Probing (without Simple Tabulation): 99.76
- master with Quadratic Probing (without Simple Tabulation): 29.97
- master with Simple Tabulation: 15.76
- master with Linear Probing and Simple Tabulation: 24.23
- master with Quadratic Probing and Simple Tabulation: 13.73
master refers to ruby 2.8.0dev:
(2020-05-07T16:22:38Z master 7ded8fd) [x86_64-linux].
I tried with 8 x Intel i5-8265U.
This prove the potential of Simple Tabulation to improve current Ruby implementation. For more details check the project report: latex/RubyTabulation_Project.pdf.
Code published under GNU GENERAL PUBLIC LICENSE v3 (see LICENSE).