https://github.com/ythecombinator/gammafn

🔢 Gamma function (Γ) from mathematics in Swift.
https://github.com/ythecombinator/gammafn

approximation factorial gamma lanczos mathematics

Last synced: 15 days ago
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🔢 Gamma function (Γ) from mathematics in Swift.

• Host: GitHub
• URL: https://github.com/ythecombinator/gammafn
• Owner: ythecombinator
• License: mit
• Created: 2017-08-07T06:51:29.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-08-16T03:49:40.000Z (over 7 years ago)
• Last Synced: 2024-11-17T15:34:52.208Z (3 months ago)
• Topics: approximation, factorial, gamma, lanczos, mathematics
• Language: Swift
• Homepage:
• Size: 51.8 KB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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	🔢 gamma function (Γ) from mathematics in Swift 🔢









    





    





    





    





    





    








---

## 📚 Table of Contents

- [Installation](#-installation)

- [Getting Started](#-getting-started)

- [License](#️-license)

## 📦 Installation

You just need to add this package as a dependency in your `Package.swift`:

```swift

let package = Package(

    name: "MyProject",

    dependencies: [

        .Package(url: "https://github.com/ythecombinator/GammaFn.git", majorVersion: 1),

        // ...

    ]

    // ...

)

```

## 🚀 Getting Started

### `gamma(for: Double) -> Double`

It returns the gamma function over `z`.

> *Note*: Complex ( `ℂ` ) numbers aren't supported–only Reals ( `ℝ` ).

```swift

import GammaFn

// Creating a simple `Double` value which we intend to pass to our Γ function–which is a static method from `Double`:

let simpleValue1: Double = 6.0

let resultValue1 = Double.gamma(for value: simpleValue1)

// => 120.0000000000002

// Another valid approach is accessing the property `gammaValue` from any `Double` value:

let simpleValue2: Double = 12.0

let resultValue2 = simpleValue2.gammaValue

// => 39916800.00000004

```

### `logForGamma(of: Double) -> Double`

It returns the natural log of the gamma function for `z`.

> *Note*: This function is used internally by the [spouge approximation](https://en.wikipedia.org/wiki/Spouge's_approximation) to compute large values.

```swift

import GammaFn

// Creating a simple `Double` value which we intend to pass to our Γ function–which is a static method from `Double`:

let simpleValue3: Double = 9.0

let resultValue3 = Double.gamma(for value: simpleValue3)

// => 10.64917311666183

// Accessing the property `logValueForGamma` from any `Double` value is valid as well:

let simpleValue4: Double = 112.0

let resultValue4 = simpleValue4.logValueForGamma

// => 415.0403783916892

```

## ⚖️ License

[GammaFn](https://github.com/ythecombinator/GammaFn) is distributed under

the MIT License, available in this repository.

All contributions are assumed to be also licensed under the same.