MooseUnits

MooseUnits is a physical units parsing and conversion helper class. A unit object can be constructed form a string (e.g. N*m, eV/at, kg*(m/s)^2, 1/s, m^-3). The unit parser supports the *,/, and ^ operators as well as parenthesis (, ). The argument of the ^ operator is expected to be a positive or negative integer.

Upon parsing all units are resolved to a combination of the seven base SI units (m, g, s, A, K, mol, cd) with their respective exponents and a prefactor. A canonical form is generated that permits unit comparisons to determine conformity (i.e. whether two units can be converted between).

MooseUnits supports prefixing all units with a metric prefix ranging from Y (yotta) to y (yocto).

Supported derived units

The following units are currently supported

Symbol	Base units	Name	Description
`Ohm`	$var element = document.getElementById("moose-equation-04bf29fe-dbcf-4b73-a110-c375472e33b2");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-3}\\cdot \\text{A}^{-2}", element, {displayMode:false,throwOnError:false});$	Ohm	resistance, impedance, reactance
`atm`	$var element = document.getElementById("moose-equation-b311f8bd-5140-4154-80f5-55dbf00b656d");katex.render("101325\\, \\text{kg}\\cdot \\text{m}^{-1}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Standard atmosphere	pressure
`eV`	$var element = document.getElementById("moose-equation-fa5a5ddc-1106-4e13-83cb-2759c3a6e299");katex.render("1.60218\\cdot10^{-19}\\, \\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	electron Volt	energy
`erg`	$var element = document.getElementById("moose-equation-31ea2b65-6a13-4cb9-9b58-932974f0a82f");katex.render("10^{-7}\\, \\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Erg	energy
`degC`	$var element = document.getElementById("moose-equation-a0e5a077-930b-4b28-a729-b0904958df45");katex.render("\\text{K}", element, {displayMode:false,throwOnError:false});$	Celsius	temperature - As long as this unit stands alone the additive shift in the scale is taken into account. In all other cases this unit behaves like Kelvin
`degF`	$var element = document.getElementById("moose-equation-b571f3f7-0599-4562-85d0-fa6495a0b725");katex.render("\\frac59\\,\\text{K}", element, {displayMode:false,throwOnError:false});$	Fahrenheit	temperature - As long as this unit stands alone the additive shift in the scale is taken into account. In all other cases this unit behaves like Rankine
`degR`	$var element = document.getElementById("moose-equation-3f808d88-9a98-4740-8e69-f6cde0cdb4a4");katex.render("\\frac59\\,\\text{K}", element, {displayMode:false,throwOnError:false});$	Rankine	temperature
`Ang`	$var element = document.getElementById("moose-equation-6e4affa9-266a-42d2-9882-65a8457251b4");katex.render("10^{-10}\\, \\text{m}", element, {displayMode:false,throwOnError:false});$	Angstrom	length
`m`	$var element = document.getElementById("moose-equation-9497c659-286d-41f9-bad1-402ad9bc1b57");katex.render("\\text{m}", element, {displayMode:false,throwOnError:false});$	meter	length
`g`	$var element = document.getElementById("moose-equation-e3fc2592-00c6-4a34-b3d8-825cef9c7886");katex.render("0.001\\, \\text{kg}", element, {displayMode:false,throwOnError:false});$	gram	mass
`s`	$var element = document.getElementById("moose-equation-f15e5ce1-d745-45fa-bfef-d50b45094fb1");katex.render("\\text{s}", element, {displayMode:false,throwOnError:false});$	second	time
`A`	$var element = document.getElementById("moose-equation-fbc36014-d0b8-4cf2-8bb8-3cdfb3ea3840");katex.render("\\text{A}", element, {displayMode:false,throwOnError:false});$	Ampere	electric current
`K`	$var element = document.getElementById("moose-equation-7174832e-4e39-4968-886c-721a3d68a071");katex.render("\\text{K}", element, {displayMode:false,throwOnError:false});$	Kelvin	temperature
`mol`	$var element = document.getElementById("moose-equation-6b550bc7-2101-4104-afee-b6d57876f86a");katex.render("6.02214076e23\\cdot10^{23}\\, \\text{at}", element, {displayMode:false,throwOnError:false});$	mole	amount of substance
`cd`	$var element = document.getElementById("moose-equation-6c106384-f3f1-49ec-b48d-05ddf64e150a");katex.render("\\text{cd}", element, {displayMode:false,throwOnError:false});$	candela	luminous intensity
`N`	$var element = document.getElementById("moose-equation-76ea9d72-8fe7-49ea-b0f4-2c059853a7b6");katex.render("\\text{kg}\\cdot \\text{m}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Newton	force, weight
`Pa`	$var element = document.getElementById("moose-equation-c51a181e-6f04-4d95-b187-598c5e53540a");katex.render("\\text{kg}\\cdot \\text{m}^{-1}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Pascal	pressure, stress
`J`	$var element = document.getElementById("moose-equation-50a69267-e221-494f-a15f-501038a5644d");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Joule	energy, work, heat
`cal`	$var element = document.getElementById("moose-equation-a090ed24-28c0-47ae-9744-9583fcd880f7");katex.render("4.184\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Calorie	energy, work, heat
`W`	$var element = document.getElementById("moose-equation-88ba35c2-554e-4e37-962a-54cbcf6e0f09");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-3}", element, {displayMode:false,throwOnError:false});$	Watt	power, radiant flux
`C`	$var element = document.getElementById("moose-equation-6b45e0a0-c3ec-4253-bc2d-8b5b3db44086");katex.render("\\text{A}\\cdot \\text{s}", element, {displayMode:false,throwOnError:false});$	Coulomb	electric charge
`V`	$var element = document.getElementById("moose-equation-dcfeb8ac-23dd-4a99-9844-48dca0b6bfa0");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-3}\\cdot \\text{A}^{-1}", element, {displayMode:false,throwOnError:false});$	Volt	voltage (electrical potential), emf
`F`	$var element = document.getElementById("moose-equation-76cf8859-6376-45d0-9a06-aa825892b44e");katex.render("\\text{kg}^{-1}\\cdot \\text{m}^{-2}\\cdot \\text{s}^{4}\\cdot \\text{A}^{2}", element, {displayMode:false,throwOnError:false});$	Farad	capacitance
`S`	$var element = document.getElementById("moose-equation-fbe55c7a-9828-49aa-a77c-c6bb2b4b4aab");katex.render("\\text{kg}^{-1}\\cdot \\text{m}^{-2}\\cdot \\text{s}^{3}\\cdot \\text{A}^{2}", element, {displayMode:false,throwOnError:false});$	Siemens	electrical conductance
`Wb`	$var element = document.getElementById("moose-equation-491a913c-1f2d-4496-9038-e8dff1d84d22");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}\\cdot \\text{A}^{-1}", element, {displayMode:false,throwOnError:false});$	Weber	magnetic flux
`T`	$var element = document.getElementById("moose-equation-571571a8-69b9-461e-999b-09403679adfb");katex.render("\\text{kg}\\cdot \\text{s}^{-2}\\cdot \\text{A}^{-1}", element, {displayMode:false,throwOnError:false});$	Tesla	magnetic flux density
`H`	$var element = document.getElementById("moose-equation-e88bceaa-971b-4c3a-b669-fd976efadf82");katex.render("\\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}\\cdot \\text{A}^{-2}", element, {displayMode:false,throwOnError:false});$	Henry	inductance
`Ba`	$var element = document.getElementById("moose-equation-939287d7-e94d-4287-9522-27dfe7351ed2");katex.render("0.1\\, \\text{kg}\\cdot \\text{m}^{-1}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	barye	Pressure
`dyn`	$var element = document.getElementById("moose-equation-10d274d4-163b-48c0-9cca-0cba736335d0");katex.render("10^{-5}\\, \\text{kg}\\cdot \\text{m}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	dyne	force, weight
`ft`	$var element = document.getElementById("moose-equation-8873d4c9-fdbf-40a5-b1a5-5bd6172fae23");katex.render("0.3048\\, \\text{m}", element, {displayMode:false,throwOnError:false});$	Foot	length
`in`	$var element = document.getElementById("moose-equation-e636dc36-5bdb-4461-8db1-05b9665783b8");katex.render("0.0254\\, \\text{m}", element, {displayMode:false,throwOnError:false});$	Inch	length
`lb`	$var element = document.getElementById("moose-equation-3b25c2f5-88c9-4bfa-9d94-ca60a11ca367");katex.render("0.45359237\\, \\text{kg}", element, {displayMode:false,throwOnError:false});$	pound	mass
`lbf`	$var element = document.getElementById("moose-equation-fc5a20b2-c052-40f1-8bb4-a503c9af50f3");katex.render("4.4482216152605\\, \\text{kg}\\cdot \\text{m}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	pound-force	force
`psi`	$var element = document.getElementById("moose-equation-e0e65357-f87c-4263-a691-143f3d1b22ec");katex.render("6894.757\\, \\text{kg}\\cdot \\text{m}^{-1}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	pound-force per square inch	pressure, stress
`BTU`	$var element = document.getElementById("moose-equation-c88aebe8-19cc-4150-9da9-d63a87336013");katex.render("1055.06\\, \\text{kg}\\cdot \\text{m}^{2}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	ISO 31-4 British thermal unit	heat
`bar`	$var element = document.getElementById("moose-equation-7cc09844-aadc-47c5-9a44-2f071898d5c1");katex.render("10^5\\, \\text{kg}\\cdot \\text{m}^{-1}\\cdot \\text{s}^{-2}", element, {displayMode:false,throwOnError:false});$	Bar	pressure, stress
`h`	$var element = document.getElementById("moose-equation-1fdabbf3-32fc-4c2c-87cb-dc033648e277");katex.render("3600\\, \\text{s}", element, {displayMode:false,throwOnError:false});$	hour	time
`day`	$var element = document.getElementById("moose-equation-417e423a-aad8-438f-ac46-9d16bbd38597");katex.render("86400\\, \\text{s}", element, {displayMode:false,throwOnError:false});$	day	time (`d` would create an ambiguity between centi-day and candela)
`year`	$var element = document.getElementById("moose-equation-1a478149-5041-469a-bafd-780a5832ac32");katex.render("365.25\\cdot86400\\, \\text{s}", element, {displayMode:false,throwOnError:false});$	annum	time (Julian calendar year, `a` would create an ambiguity between Peta-annum and Pascal)
`l`	$var element = document.getElementById("moose-equation-cbbcf5da-a4c7-467b-a7dc-44509797f118");katex.render("0.001\\, \\text{m}^{3}", element, {displayMode:false,throwOnError:false});$	liter	volume
`u`	$var element = document.getElementById("moose-equation-77d97070-4895-4ff6-9cfb-d175e2644bf6");katex.render("1.6605390666\\cdot10^{-27}\\, \\text{kg}^{3}", element, {displayMode:false,throwOnError:false});$	unified atomic mass unit	mass
`at`	$var element = document.getElementById("moose-equation-8fd4eeb4-c8a2-4507-8abe-8e3cc32b8659");katex.render("\\text{at}", element, {displayMode:false,throwOnError:false});$	atom	single count of substance

Operators

Unit objects support the * and / operators to multiply and divide units respectively. An overload of std::pow is provided to exponentiate units.

The == equal operator is implemented for comparison of two units and a unit and a real number. It returns true if the two units are exactly identical including the prefactor. A comparison that omits the prefactor is provided by the conformsTo method.

A unit is considered equal to a real number if all its base unit exponents are zero and the prefactor matches the real number.

Dimension check

In addition to the conformsTo check a few bool member functions are provided to check if the unit represents a given physical dimension.

isLength()
isTime()
isMass()
isCurrent()
isTemperature()

Output

MooseUnits objects can be output to streams using the << operator. The output consists of the prefactor and the SI base units with their respective exponents. Two stream manipulators are provided to toggle between plain text and LaTeX formatted output of the units.

MooseUnits

Supported derived units

Operators

Dimension check

Output

See also