log1+ ( x -- y ) (original) (raw)
log1+ ( x -- y )
Factor handbook » The language » Numbers » Mathematical functions » Powers and logarithms
| Prev: | log ( x -- y ) |
|---|---|
| Next: | log10 ( x -- y ) |
Inputs
| x | a number |
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Outputs
| y | a number |
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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
Methods
USING: kernel math math.functions math.libm ;
M: float log1+
dup -1.0 >= [ flog1+ ] [ 1.0 + 0.0 rect> log ] if ; inline