log1+ ( x -- y )
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Vocabulary
math.functions

Inputs

x

a number

Outputs

y

a number

Word description
Takes the natural logarithm of 1 + x. Outputs negative infinity if 1 + x is zero. This word may be more accurate than 1 + log for very small values of x.

Definition

IN: math.functions

GENERIC: log1+ ( x -- y )

Methods

USING: kernel math math.functions math.libm ;

M: float log1+
    dup -1.0 >= [ flog1+ ] [ 1.0 + 0.0 rect> log ] if ; inline


USING: kernel math math.functions ;

M: object log1+ 1 + log ; inline