Logarithm


 * This page describes the dyadic arithmetic function. For the monadic natural logarithm function, see Natural Logarithm.

, or Log, is a dyadic scalar function which computes the logarithm of the two arguments. More precisely,  computes how much power of X equals Y, i.e. the value of R that satisfies. Logarithm shares the glyph  with the monadic arithmetic function Natural Logarithm. The glyph, a composition of the glyphs for Circular and Power  to indicate its close mathematical ties with these two functions, is a stylised tree log.

Examples
Logarithm can be used to determine how many digits are needed to write a positive integer Y in base X:

Properties
By definition, logarithm is the inverse of the power with the same base (left argument).

Reciprocal on the left or right argument gives the negated result.

Documentation

 * Dyalog
 * APLX
 * J Dictionary, NuVoc