log1p computes with accuracy the natural logarithm of its argument added by one

## Syntax

    y=log1p(x)

## Arguments

x

  real scalar, vector or matrix

y

  real scalar, vector or matrix

## Description

`log1p(x)` is the "element-wise" `log(1+x)` function. `y(i,j)=log(1 + x(i,j))`. This function, defined for `x` > -1, must be used if we want to compute `log(1+x)` with accuracy for `|x|` << 1.

## Examples

    format("e",24)
    log(1.001)
    log1p(0.001)
    log(1 + 1.e-7)
    log1p(1.e-7)
    log(1 + 1.e-20)
    log1p(1.e-20)
    format("v") //reset default format

## See also

- log