ilog2.pl -- A Collection of Numerical Snippets :: ilog2

Part of Nan.Numerics.Gist (nan/numerics/gist.pl)

This module provides predicates that implement different algorithms for the computation of the integer binary logarithm in arbitrary precision.

To the purpose of comparing efficiency, predicates in this module return the count of elementary arithmetic operations performed.

Three variants are offered which are further refinements on the naive approach that increases the bit mask by one bit at a time:

• ilog2_n/3 : Naive approach.
• ilog2_i/3 : Faster approach that uses integer arithmetic only.
• ilog2_f/3 : Even faster approach that also uses FPU-based arithmetic. % TODO!

NOTE: This module is not meant to provide production-ready Prolog code.

author

- Julio P. Di Egidio

version

- 1.1.1-beta

copyright

- 2017 Julio P. Di Egidio

license

- GNU GPLv3

ilog2_n(+X:posint, -Y:nonnegint, -C:nonnegint) is det

ilog2_i(+X:posint, -Y:nonnegint, -C:nonnegint) is det

ilog2_test(:G:call, -C:nonnegint) is det

ilog2_print(:G:call, +L:posint, +H:posint, +X0:nonnegint) is det