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https://github.com/eriksencosta/math-common
Math conventions to reduce boilerplate code
https://github.com/eriksencosta/math-common
kotlin math rounding
Last synced: 2 months ago
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Math conventions to reduce boilerplate code
- Host: GitHub
- URL: https://github.com/eriksencosta/math-common
- Owner: eriksencosta
- License: apache-2.0
- Created: 2024-03-27T02:25:00.000Z (10 months ago)
- Default Branch: trunk
- Last Pushed: 2024-04-16T00:23:04.000Z (9 months ago)
- Last Synced: 2024-08-02T09:28:57.755Z (6 months ago)
- Topics: kotlin, math, rounding
- Language: Kotlin
- Homepage: https://blog.eriksen.com.br/opensource/math-common/
- Size: 81.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
- Security: SECURITY.md
Awesome Lists containing this project
- awesome-kotlin - Math Common - Math conventions to reduce boilerplate code on rounding and exponentiation (Libraries)
README
# Math Common
Math conventions to reduce boilerplate code.
## Installation
Add Math Common to your Gradle build script:
```kotlin
repositories {
mavenCentral()
}
dependencies {
implementation("com.eriksencosta.math:common:0.2.0")
}
```
If you're using Maven, add to your POM xml file:
```xml
com.eriksencosta.math
common
0.2.0
```
Math Common is not compatible with the Android SDK at the moment.
## Usage
### Rounding
The library provides the `Rounding` [strategy](https://refactoring.guru/design-patterns/strategy) to make rounding
easier:
```kotlin
1.25.round(1) // 1.3
```
By default, the [RoundingMode.HALF_EVEN](https://docs.oracle.com/javase/8/docs/api/java/math/RoundingMode.html#HALF_EVEN) is
used for rounding (it is the rounding logic commonly taught at school). If you want to use a different mode, create a
`Rounding` and use it:
```kotlin
import java.math.RoundingMode
val rounding = Rounding.to(2, RoundingMode.FLOOR)
rounding.round(1.257) // 1.25
rounding.round(1.253) // 1.25
// Alternatively:
1.257.round(rounding) // 1.25
1.253.round(rounding) // 1.25
```
If you want to round the result of a calculation, use the overloaded `round()` method which accepts a function as
parameter:
```kotlin
Rounding.to(2).round { 3.14159 * 10.0.squared() } // 314.16
```
Alternatively:
```kotlin
{ 3.14159 * 10.0.squared() }.round(2) // 314.16
```
### Exponentiation
The extension functions `squared` and `cubed` are available for `BigDecimal`, `Double`, `Float`, `Long`, and `Int`:
```kotlin
2.squared() // 4
2.0.cubed() // 8.0
```
## Performance
The library caches the `Rounding` objects by default. You can configure the cache by calling `configureCache()`:
```kotlin
configureCache {
maximumItems = 100
expirationTime = 2
expirationTimeUnit = TimeUnit.HOURS
}
Rounding.to(2) === Rounding.to(2) // true
```
The previous example will configure the cache to store up to 100 `Rounding` objects, and a cached object will live for up to two hours. If you want to disable the cache, call `disableCache()`:
```kotlin
disableCache()
Rounding.to(2) === Rounding.to(2) // false
```
## API documentation
Read the [API documentation](https://blog.eriksen.com.br/opensource/math-common/) for further details.
## License
[The Apache Software License, Version 2.0](https://choosealicense.com/licenses/apache/)