Method of multiplying small numbers using lookup tables
The Irish logarithm was a system of number manipulation invented by Percy Ludgate for machine multiplication. The system used a combination of mechanical cams as lookup tables and mechanical addition to sum pseudo-logarithmic indices to produce partial products, which were then added to produce results.[1]
The technique is similar to Zech logarithms (also known as Jacobi logarithms), but uses a system of indices original to Ludgate.[2]
^Randall, Brian (October 1982). "From Analytical Engine to Electronic Digital Computer:The Contributions of Ludgate, Torres, and Bush" (PDF). Annals of the History of Computing. 4 (4): 20. Archived (PDF) from the original on 2019-12-28. Retrieved 2019-12-28.
^de Man, Andries. "Irish Logarithms Part 2 – Calculating History". sites.google.com. Archived from the original on 2020-02-23. Retrieved 2019-12-28.
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