log {base} | R Documentation |

`log`

computes natural logarithms,
`log10`

computes common (i.e., base 10) logarithms, and
`log2`

computes binary (i.e., base 2) logarithms.
The general form `logb(x, base)`

computes logarithms with base
`base`

(`log10`

and `log2`

are only special cases).

`log1p(x)`

computes *log(1+x)* accurately also for
*|x| << 1* (and less accurately when *x is approximately -1*).

`exp`

computes the exponential function.

`expm1(x)`

computes *exp(x) - 1* accurately also for
*|x| << 1*.

log(x, base = exp(1)) logb(x, base = exp(1)) log10(x) log2(x) exp(x) expm1(x) log1p(x)

`x` |
a numeric or complex vector. |

`base` |
positive number. The base with respect to which
logarithms are computed. Defaults to e=`exp(1)` . |

`exp`

and `log`

are generic functions: methods can be defined
for them individually or via the `Math`

group generic.

A vector of the same length as `x`

containing the transformed
values. `log(0)`

gives `-Inf`

(when available).

`log`

and `logb`

are the same thing in **R**, but `logb`

is preferred if `base`

is specified, for S-PLUS compatibility.

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.
(for `log`

, `\log10`

and `exp`

.)

Chambers, J. M. (1998)
*Programming with Data. A Guide to the S Language*.
Springer. (for `logb`

.)

`Trig`

,
`sqrt`

,
`Arithmetic`

.

log(exp(3)) log10(1e7)# = 7 x <- 10^-(1+2*1:9) cbind(x, log(1+x), log1p(x), exp(x)-1, expm1(x))

[Package *base* version 2.2.1 Index]