Surge

Surge is a Swift library that uses the Accelerate framework to provide high-performance functions for matrix math, digital signal processing, and image manipulation.

Accelerate exposes SIMD instructions available in modern CPUs to significantly improve performance of certain calculations. Because of its relative obscurity and inconvenient APIs, Accelerate is not commonly used by developers, which is a shame, since many applications could benefit from these performance optimizations.

Surge aims to bring Accelerate to the mainstream, making it as easy (and nearly as fast, in most cases) to perform computation over a set of numbers as for a single member.

Though, keep in mind: Accelerate is not a silver bullet. Under certain conditions, such as performing simple calculations over a small data set, Accelerate can be out-performed by conventional algorithms. Always benchmark to determine the performance characteristics of each potential approach.

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Curious about the name Surge? Back in the mid 90's, Apple, IBM, and Motorola teamed up to create AltiVec (a.k.a the Velocity Engine), which provided a SIMD instruction set for the PowerPC architecture. When Apple made the switch to Intel CPUs, AltiVec was ported to the x86 architecture and rechristened Accelerate. The derivative of Accelerate (and second derivative of Velocity) is known as either jerk, jolt, surge, or lurch, hence the name of this library.

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Installation

The infrastructure and best practices for distributing Swift libraries are currently in flux during this beta period of Swift & Xcode. In the meantime, you can add Surge as a git submodule, drag the Surge.xcodeproj file into your Xcode project, and add Surge.framework as a dependency for your target.

Surge uses Swift 5. This means that your code has to be written in Swift 5 due to current binary compatibility limitations.

Swift Package Manager

To use Swift Package Manager add Surge to your Package.swift file:

let package = Package(
    name: "myproject",
    dependencies: [
        .package(url: "https://github.com/mattt/Surge.git", .upToNextMajor(from: "2.0.0")),
    ],
    targets: [
        .target(
            name: "myproject",
            dependencies: ["Surge"]),
    ]
)

Then run swift build.

CocoaPods

To use CocoaPods add Surge to your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!

target '<Your Target Name>' do
    pod 'Surge', '~> 2.0.0'
end

Then run pod install.

Carthage

To use Carthage add Surge to your Cartfile:

github "mattt/Surge" ~> 2.0.0

Then run carthage update and use the framework in Carthage/Build/<platform>.

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Inventory

Surge functions are named according to their corresponding "Math.h" functions, where applicable (omitting f and d affixes, since type information is communicated and enforced by the language's type system).

Arithmetic

• sum: Summation
• asum: Absolute summation
• max: Maximum
• min: Minimum
• mean: Arithmetic mean
• meamg: Mean of magnitudes
• measq: Mean of squares
• add: Addition
• sub: Subtraction
• mul: Multiplication
• div: Division
• mod: Modulo
• remainder: Remainder
• sqrt: Square root

Auxiliary

• abs: Absolute value
• ceil: Ceiling function
• copysign: Signum function
• floor: Floor function
• rec: Multiplicative inverse
• round: Rounding function
• trunc: Integer truncation

Convolution

• conv: Convolution
• xcorr: Cross correlation

Exponential

• exp: Exponential function
• exp2: Base-2 exponential function
• log: Base-e logarithm
• log2: Base-2 logarithm
• log10: Base-10 logarithm
• logb: Base-radix logarithm

FFT

• fft: Fast fourier transform

Hyperbolic

• sinh: Hyperbolic sine
• cosh: Hyperbolic cosine
• tanh: Hyperbolic tangent
• asinh: Inverse hyperbolic cosine
• acosh: Inverse hyperbolic cosine
• atanh: Inverse hyperbolic cosine

Matrix

• sum: Axis-wise summation
• add: Matrix addition
• sub: Matrix subtraction
• mul: Matrix multiplication
• div: Matrix division
• inv: Matrix inversion
• transpose: Matrix transpose
• det: Determinant
• pow: Element-wise power
• exp: Element-wise exponential function
• elmul: Element-wise matrix multiplication

Power

• pow: Power

Trigonometric

• sincos
• sin: Sine function
• cos: Cosine function
• tan: Tangent function
• asin: Arc sine function
• acos: Arc cosine function
• atan: Arc tangent function
• rad2deg: Radians to degrees
• deg2rad: degrees to radians

Usage

Computing Sum of [Double]

import Surge

let n = [1.0, 2.0, 3.0, 4.0, 5.0]
let sum = Surge.sum(n) // 15.0

Computing Product of Two [Double]s

import Surge

let a = [1.0, 3.0, 5.0, 7.0]
let b = [2.0, 4.0, 6.0, 8.0]

let product = Surge.mul(a, b) // [2.0, 12.0, 30.0, 56.0]

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License

Surge is available under the MIT license. See the LICENSE file for more info.