lognum

Note: This is taken from the Chicken Wiki, where a more recent version could be available.

Introduction

A logarithmic number system (LNS) is an arithmetic system for representing real numbers. In LNS, a number X, is represented by the logarithm L of its absolute value:

   X -> { s, L = \log_b(|X|) }

where s denotes the sign of X (s = 1 if X > 0 and s = -1 if X < 0).

Requires

syntax-case

matchable

datatype

Library procedures

<procedure>lognum?:: X -> BOOL</procedure> <procedure>lognum-sign:: X -> INTEGER</procedure> <procedure>lognum-value:: X -> NUMBER</procedure> <procedure>number->lognum:: NUMBER -> LOGNUM</procedure> <procedure>lognum->number:: LOGNUM -> NUMBER</procedure> <procedure>lognum+:: A * B -> X</procedure> <procedure>lognum-:: A * B -> X</procedure> <procedure>lognum*:: A * B -> X</procedure> <procedure>lognum/:: A * B -> X</procedure> <procedure>lognum-neg:: A -> B</procedure> <procedure>lognum-abs:: A -> B</procedure> <procedure>lognum-signum:: A -> B</procedure> <procedure>lognum-recip:: A -> B</procedure>

Authors

Ivan Raikov

Version

1.0

Initial version

License

Copyright 2009 Ivan Raikov and the Okinawa Institute of Science and Technology.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A full copy of the GPL license can be found at <http://www.gnu.org/licenses/>.