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https://github.com/uhoefel/units
A library for handling units in Java.
https://github.com/uhoefel/units
Last synced: 11 days ago
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A library for handling units in Java.
- Host: GitHub
- URL: https://github.com/uhoefel/units
- Owner: uhoefel
- License: mit
- Created: 2020-11-08T14:28:19.000Z (about 4 years ago)
- Default Branch: master
- Last Pushed: 2024-06-20T09:19:28.000Z (7 months ago)
- Last Synced: 2024-06-20T23:20:12.865Z (6 months ago)
- Language: Java
- Size: 270 KB
- Stars: 4
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Units
[](https://github.com/uhoefel/units/issues)
[](https://github.com/uhoefel/units/stargazers)
[](https://doi.org/10.5281/zenodo.4262929)
[](https://search.maven.org/search?q=g:%22eu.hoefel%22%20AND%20a:%22units%22)
[](https://choosealicense.com/licenses/mit/)
Units is a [Java](https://openjdk.java.net/) library designed to handle units and constants.
It is designed to handle string based units as well as sharper defined units.
Some of the supported features include:
- conversions of values, e.g.:
```java
Units.convert(3, "m", "mm");
Units.convert(3, SiBaseUnit.METER, Unit.of("mm"));
```
would both return `3000`.
- simplification of string based units, e.g.:
```java
Units.simplify("kg^3 m^4 s^-6 A^-1");
```
would return `"J^2 T"`.
- finding the names of a unit in a specific context, e.g.:
```java
Units.inContext("lx s", UnitContextMatch.COMPATIBLE, PhysicsContext.PHOTOMETRY)
```
would return a navigable set containing `("luminous exposure")`.
- supports [SI units](https://www.bipm.org/en/publications/si-brochure/), binary units, [imperial units](https://www.legislation.gov.uk/ukpga/1985/72), [US customary units](https://en.wikipedia.org/wiki/United_States_customary_units), [atomic units](https://en.wikipedia.org/wiki/Hartree_atomic_units), [planck units](https://en.wikipedia.org/wiki/Planck_units) and many more. The user can also easily define own units.
- fully supports arbitrary logarithmic units, e.g.
```java
LevelUnit.BEL.inReferenceTo(1, Unit.of("mV")); // automatically determines ref type -> root power
LevelUnit.BEL.inReferenceTo(1, Unit.of("W"), LevelUnitReferenceType.POWER); // specify type explicitly
Unit.of("ln(re 1 nA)") == LevelUnit.NEPER.inReferenceTo(1, Unit.of("nA")); // true
```
- supports SI prefixes, binary prefixes and allows the user to easily implement own prefixes
- Can handle unknown units if not relevant, e.g.:
```java
Units.convert(3, "m^2 this_is_not_a_unit", "mm^2 this_is_not_a_unit");
```
would return `3e6`, as the unknown unit `this_is_not_a_unit` is the same on both sides of the conversion.
- for performance critical parts of the code one can obtain the conversion factor (if the conversion is purely multiplicative), e.g.:
```java
Units.factor("kg", "t");
```
will return `1e-3`.
- Allows to check for convertibility
```java
Units.convertible("s", "min");
```
will return `true`.
- tightly integrated in the [coordinates](https://github.com/uhoefel/coordinates) library
The constants are implemented via a `Constant` interface that supports e.g.:
- definition of own constants, e.g.
```java
// (3 ± 0.2) mole
Constant.of(3, 0.2, "mole");
```
- chaining commands, e.g.
```java
// constant with the distance traveled by light in vacuum in (2 ± 0) seconds as value
PhysicsConstant.SPEED_OF_LIGHT_IN_VACUUM.mul(2, 0, SiBaseUnit.SECOND);
// constant of the elementary charge per (electron) mass
PhysicsConstant.ELEMENTARY_CHARGE.div(PhysicsConstant.ELECTRON_MASS);
Constant c = Constant.of(3, 0.2, "mole");
PhysicsConstant.SHIELDING_DIFFERENCE_OF_T_AND_P_IN_HT.mul(c);
```
- (simple) uncertainty propagation
- the `Constant` interface provides default implementations for the `Texable` interface from the [jatex](https://github.com/uhoefel/jatex) module, such that a constant can easily return proper LaTeX code.
- properly documented implementations for most of the physics constants as defined by NIST, as well as some mathematical constants.
Installation
============
The artifact can be found at maven central:
```xml
eu.hoefel
units
4.1.1
```
Requirements
============
Units is designed to work with Java 17+.