Surge

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

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.

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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

Use Swift Package Manager

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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
• asum
• max
• min
• mean
• meamg
• measq
• add
• sub
• mul
• div
• mod
• remainder
• sqrt
• sum of squared values

Auxilliary

• abs
• ceil
• copysign
• floor
• rec
• round
• trunc

Convolution

• conv
• xcorr

Exponential

• exp
• exp2
• log
• log2
• log10
• logb

FFT

• fft

Hyperbolic

• sinh
• cosh
• tanh
• asinh
• acosh
• atanh

Matrix

• add
• mul
• inv
• transpose
• negate

You can also initialize matrices with generator functions for the elements, thus enabling the user to create matrices from gaussian distributions for example.

Power

• pow

Trigonometric

• sincos
• sin
• cos
• tan
• asin
• acos
• atan
• rad2deg
• deg2rad

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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Performance

Initial benchmarks on iOS devices and the iOS simulator indicate significant performance improvements over a conventional Swift implementation.

import Surge

let numbers: [Double] = ...
var sum: Double = 0.0

// Naïve Swift Implementation
sum = reduce(numbers, 0.0, +)

// Surge Implementation
sum = Surge.sum(numbers)

(Time in milliseconds, Optimization Level -Ofast)

n	Swift	Surge	Δ
100	0.269081	0.004453	~60x
100000	251.037254	0.028687	~9000x
100000000	239474.689326	57.009841	~4000x

Surge's performance characteristics have not yet been thoroughly evaluated, though initial benchmarks show incredible promise. Further investigation is definitely warranted.

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License

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