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< [[Math]] [[Physics]] > The units module comes with ConTeXt's default distribution. In MkIV the units module comes built-in, however there is still the option to access the old module and its commands via {{cmd|usemodule}}[units] Additional documentation about units in MkIV is available from the [[http://www.pragma-ade.nl/general/manuals/units-mkiv.pdf Units manual]] ===Using the built-in command=== In MkIV you can use the built-in {{cmd|unit}} command to parse units. Some examples of this are shown below: <texcode>10 \unit{km/h}\unit{10 km/h}\unit{~1 km/h}\unit{KiloMeter/Hour}\unit{10 cubic meter / second}\unit{kilo pascal square meter / second}\unit{kilo pascal square meter / kelvin second }$\unit{10 AC}$\frac{10 \unit{m/s}}{20 \unit{m/s}}${\ss 30 \unit{kilo pascal square meter / second kelvin}}\unit{123.22^-3 km/s}\unit{123.22e-3 km/s}</texcode> ConTeXt will take care of spacing and formatting. The parser is fairly flexible, and the following all work and give the same output. {| ! width="45%"| ! width="10%"| ! width="45%"| |- | <texcode>\unit{10 kg}\unit{10kg}\unit{10 kilo gram}\unit{10 kilogram}\unit{10 Kilo Gram}\unit{10 KiloGram}</texcode>||<context mode=mkiv>\startlines\unit{10 kg}\unit{10kg}\unit{10 kilo gram}\unit{10 kilogram}\unit{10 Kilo Gram}\unit{10 KiloGram}\stoplines</context>|} The command works in text as well as in math mode and spaces are normally ignored. You can define your own command:  <texcode>\defineunits[un][alternative=text,separator=medium]</texcode> Valid separators are <code>cdot</code>, <code>big</code>, <code>medium</code>, and <code>space</code> with the first being the default. You can later tune the rendering with  <texcode>\setupunits[un][separator=cdot]</texcode> In due time there will be a few more options. Numbers are formatted cf the digits mechanism (not discussed here). ===Using the old units module===

* This runtime loadable module implements a way of defining units. The core macro is <{{cmd>|dimension</cmd>}}, a rather clever one that is able to cooperate with some other dimension related macros. As said, this module enables user to enter:

(Note that the space after <{{cmd>|Second</cmd> }} needs to be explicitly specified; otherwise, it will get eaten.)

* Units act upon signals that they insert in the text, in case no quantity is given you need to start the unit sequence using <{{cmd>|Unit</cmd>}}

This definition means that we can ask for the meaning of a unit using <{{cmd>|unitmeaning</cmd> }} and get a list of used units by saying <{{cmd>|placelistofunits</cmd>}}.

We have to use the command <{{cmd>|unitmeaning</cmd> }} instead of <{{cmd>|meaning</cmd>}}, simply because the latter is a TeX primitive we don't want to lose. We use the label text mechanism for translations.

[[httphttps://www.unceasyunitconverter.educom/~rowlettEasy Unit Converter]] * Prefixes: {{cmd|Atto}} a, {{cmd|Femto}} f, {{cmd|Pico}} p, {{cmd|Nano}} n, {{cmd|Micro}} μ, {{cmd|Milli}} m, {{cmd|Centi}} c, {{cmd|Deci}} d, {{cmd|Hecto}} h, {{cmd|Kilo}} k, {{cmd|Mega}} M, {{cmd|Giga}} G, {{cmd|Tera}} T, {{cmd|Peta}} P, {{cmd|Exa}} E (missing: {{cmd|Zetta}} Z, {{cmd|Yotta}} Y, {{cmd|Zepto}} z, {{cmd|Yocto}} y)* Suffixes: {{cmd|Linear}} <sup>1</unitssup>, {{cmd|Square}} <sup>2</index.html How Many? A Dictionary of Units of Measurement]]sup>, {{cmd|Cubic}} ³, {{cmd|Inverse}} or {{cmd|ILinear}} ^-1, {{cmd|ISquare}} ^-2, {{cmd|ICubic}} ^-3* Fraction: {{cmd|Per}}, {{cmd|Percent}}, {{cmd|Permille}}, {{cmd|Promille}}* Time: {{cmd|Second}}, {{cmd|Minute}}, {{cmd|Hour}}, {{cmd|Day}}, {{cmd|Month}}, {{cmd|Year}}* Length, Area, Volume: {{cmd|Meter}}, {{cmd|Angstrom}}, {{cmd|Foot}}, {{cmd|Inch}}, {{cmd|Liter}}* Mass, Force and Pressure: {{cmd|Gram}}, {{cmd|Atom}}, {{cmd|Newton}}, {{cmd|Pascal}}, {{cmd|Mol}}, {{cmd|At}}, {{cmd|Atm}}, {{cmd|Bar}}, {{cmd|Force}}* Energy, Electricity and Magnetism: {{cmd|Joule}}, {{cmd|Watt}}, {{cmd|Cal}}, {{cmd|Farad}}, {{cmd|Henry}}, {{cmd|Ohm}}, {{cmd|Siemens}}, {{cmd|Ampere}}, {{cmd|Coulomb}}, {{cmd|Volt}}, {{cmd|Tesla}}, {{cmd|Gauss}}, {{cmd|VoltAC}}, {{cmd|VoltDC}}, {{cmd|EVolt}}, {{cmd|Weber}}* Temperature: {{cmd|Degrees}}, {{cmd|Kelvin}}, {{cmd|Celsius}}, {{cmd|Fahrenheit}}* Angle: {{cmd|Rad}}, {{cmd|Deg}}, {{cmd|Sterant}}* Frequency, Optics and Acoustics: {{cmd|Hertz}}, {{cmd|RevPerSec}}, {{cmd|RevPerMin}}, {{cmd|Candela}}, {{cmd|Lux}}, {{cmd|Bell}}* Chemistry and Radiation: {{cmd|Atom}}, {{cmd|Mol}}, {{cmd|Molair}}, {{cmd|Equivalent}}, {{cmd|Bequerel}}, {{cmd|Sievert}}, {{cmd|Gray}}* Informatics: {{cmd|Baud}}, {{cmd|Bit}}, {{cmd|Byte}}* some old dutch (not listed)

* Prefixes: <cmd>Atto</cmd> a, <cmd>Femto</cmd> f, <cmd>Pico</cmd> p, <cmd>Nano</cmd> n, <cmd>Micro</cmd> μ, <cmd>Milli</cmd> m, <cmd>Centi</cmd> c, <cmd>Deci</cmd> d, <cmd>Hecto</cmd> h, <cmd>Kilo</cmd> k, <cmd>Mega</cmd> M, <cmd>Giga</cmd> G, <cmd>Tera</cmd> T, <cmd>Peta</cmd> P, <cmd>Exa</cmd> E (missing: <cmd>Zetta</cmd> Z, <cmd>Yotta</cmd> Y, <cmd>Zepto</cmd> z, <cmd>Yocto</cmd> y)* Suffixes: <cmd>Linear</cmd> ¹, <cmd>Square</cmd> ², <cmd>Cubic</cmd> ³, <cmd>Inverse</cmd> or <cmd>ILinear</cmd> ^-1, <cmd>ISquare</cmd> ^-2, <cmd>ICubic</cmd> ^-3* Fraction: <cmd>Per</cmd>, <cmd>Percent</cmd>, <cmd>Permille</cmd>, <cmd>Promille</cmd>* Time: <cmd>Second</cmd>, <cmd>Minute</cmd>, <cmd>Hour</cmd>, <cmd>Day</cmd>, <cmd>Month</cmd>, <cmd>Year</cmd>* Length, Area, Volume: <cmd>Meter</cmd>, <cmd>Angstrom</cmd>, <cmd>Foot</cmd>, <cmd>Inch</cmd>, <cmd>Liter</cmd>* Mass, Force and Pressure: <cmd>Gram</cmd>, <cmd>Atom</cmd>, <cmd>Newton</cmd>, <cmd>Pascal</cmd>, <cmd>Mol</cmd>, <cmd>At</cmd>, <cmd>Atm</cmd>, <cmd>Bar</cmd>, <cmd>Force</cmd>10 \Mynewunit* Energy, Electricity and Magnetism: <cmd>Joule</cmd>, <cmd>Watt</cmd>, <cmd>Cal</cmd>, <cmd>Farad</cmd>, <cmd>Henry</cmd>, <cmd>Ohm</cmd>, <cmd>Siemens</cmd>, <cmd>Ampere</cmd>, <cmd>Coulomb</cmd>, <cmd>Volt</cmd>, <cmd>Tesla</cmd>, <cmd>Gauss</cmd>, <cmd>VoltAC</cmd>, <cmd>VoltDC</cmd>, <cmd>EVolt</cmd>, <cmd>Weber</cmd>* Temperature: <cmd>Degrees</cmd>, <cmd>Kelvin</cmd>, <cmd>Celsius</cmd>, <cmd>Fahrenheit</cmd>* Angle: <cmd>Rad</cmd>, <cmd>Deg</cmd>, <cmd>Sterant</cmd>* Frequency, Optics and Acoustics: <cmd>Hertz</cmd>, <cmd>RevPerSec</cmd>, <cmd>RevPerMin</cmd>, <cmd>Candela</cmd>, <cmd>Lux</cmd>, <cmd>Bell</cmd>* Chemistry and Radiation: <cmd>Atom</cmd>, <cmd>Mol</cmd>, <cmd>Molair</cmd>, <cmd>Equivalent</cmd>, <cmd>Bequerel</cmd>, <cmd>Sievert</cmd>, <cmd>Gray</cmd>* Informatics: <cmd>Baud</cmd>, <cmdcontext>Bit</cmd>, <cmd>Byte</cmd>* some old dutch (not listed)

[[Category:MathSciences]][[Category:Modules]]