# Math.units: Mathematical operations for units objects In units: Measurement Units for R Vectors

## Description

Mathematical operations for units objects

## Usage

 ```1 2``` ```## S3 method for class 'units' Math(x, ...) ```

## Arguments

 `x` object of class units `...` parameters passed on to the Math functions

## Details

Logarithms receive a special treatment by the underlying udunits2 library. If a natural logarithm is applied to some `unit`, the result is `ln(re 1 unit)`, which means natural logarithm referenced to `1 unit`. For base 2 and base 10 logarithms, the output `lb(...)` and `lg(...)` respectively instead of `ln(...)`.

This is particularly important for some units that are typically expressed in a logarithmic scale (i.e., bels, or, more commonly, decibels), such as Watts or Volts. For some of these units, the default udunits2 database contains aliases: e.g., `BW` (bel-Watts) is an alias of `lg(re 1 W)`; `Bm` (bel-milliWatts) is an alias of `lg(re 0.001 W)`; `BV` is an alias of `lg(re 1 V)` (bel-Volts), and so on and so forth (see the output of `valid_udunits()` for further reference).

Additionally, the units package defines `B`, the bel, by default (because it is not defined by udunits2) as an alias of `lg(re 1)`, unless a user-provided XML database already contains a definition of `B`, or the `define_bel` option is set to `FALSE` (see `help(units_options)`).

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22``` ```# roundings, cummulative functions x <- set_units(sqrt(1:10), m/s) signif(x, 2) cumsum(x) # trigonometry sin(x) # not meaningful x <- set_units(sqrt(1:10), rad) sin(x) cos(x) x <- set_units(seq(0, 1, 0.1), 1) asin(x) acos(x) # logarithms x <- set_units(sqrt(1:10), W) log(x) # base exp(1) log(x, base = 3) log2(x) log10(x) set_units(x, dBW) # decibel-watts set_units(x, dBm) # decibel-milliwatts ```

units documentation built on Feb. 5, 2022, 1:09 a.m.