Book Image

Machine Learning with Swift

By : Jojo Moolayil, Alexander Sosnovshchenko, Oleksandr Baiev
Book Image

Machine Learning with Swift

By: Jojo Moolayil, Alexander Sosnovshchenko, Oleksandr Baiev

Overview of this book

Machine learning as a field promises to bring increased intelligence to the software by helping us learn and analyse information efficiently and discover certain patterns that humans cannot. This book will be your guide as you embark on an exciting journey in machine learning using the popular Swift language. We’ll start with machine learning basics in the first part of the book to develop a lasting intuition about fundamental machine learning concepts. We explore various supervised and unsupervised statistical learning techniques and how to implement them in Swift, while the third section walks you through deep learning techniques with the help of typical real-world cases. In the last section, we will dive into some hard core topics such as model compression, GPU acceleration and provide some recommendations to avoid common mistakes during machine learning application development. By the end of the book, you'll be able to develop intelligent applications written in Swift that can learn for themselves.
Table of Contents (18 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Implementing multiple linear regression in Swift


The MultipleLinearRegression class contains a vector of weights, and staff for data normalization:

class MultipleLinearRegression { 
public var weights: [Double]! 
public init() {} 
public var normalization = false 
public var xMeanVec = [Double]() 
public var xStdVec = [Double]() 
public var yMean = 0.0 
public var yStd = 0.0 
... 
} 

Hypothesis and prediction:

public func predict(xVec: [Double]) -> Double { 
if normalization { 
    let input = xVec 
    let differenceVec = vecSubtract([1.0]+input, xMeanVec) 
    let normalizedInputVec = vecDivide(differenceVec, xStdVec) 
     
    let h = hypothesis(xVec: normalizedInputVec) 
     
    return h * yStd + yMean 
} else { 
    return hypothesis(xVec: [1.0]+xVec) 
} 
} 
 
private func hypothesis(xVec: [Double]) -> Double { 
var result = 0.0 
vDSP_dotprD(xVec, 1, weights, 1, &result, vDSP_Length(xVec.count)) 
return result 
} 
 
public func predict(xMat: [[Double]]) -> [Double] { 
let...