Book Image

Scala Machine Learning Projects

Book Image

Scala Machine Learning Projects

Overview of this book

Machine learning has had a huge impact on academia and industry by turning data into actionable information. Scala has seen a steady rise in adoption over the past few years, especially in the fields of data science and analytics. This book is for data scientists, data engineers, and deep learning enthusiasts who have a background in complex numerical computing and want to know more hands-on machine learning application development. If you're well versed in machine learning concepts and want to expand your knowledge by delving into the practical implementation of these concepts using the power of Scala, then this book is what you need! Through 11 end-to-end projects, you will be acquainted with popular machine learning libraries such as Spark ML, H2O, DeepLearning4j, and MXNet. At the end, you will be able to use numerical computing and functional programming to carry out complex numerical tasks to develop, build, and deploy research or commercial projects in a production-ready environment.
Table of Contents (17 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Predicting prices and evaluating the model


ShortTermPredictionServiceImpl is the class that actually performs the prediction with the given model and data. At first, it transforms PriceData into a Spark DataFrame with the scheme corresponding to the one used for training by calling transformPriceData(priceData: PriceData). Then, the model.transform(dataframe) method is called; we extract the variables we need, write into the debugger log and return to the caller:

override def predictPriceDeltaLabel(priceData: PriceData, mlModel: org.apache.spark.ml.Transformer): (String, Row) = {
        val df = transformPriceData(priceData)
        val prediction = mlModel.transform(df)
        val predictionData = prediction.select("probability", "prediction", "rawPrediction").head()
        (predictionData.get(1).asInstanceOf[Double].toInt.toString, predictionData)
        }

While running, the application collects data about the prediction output: predicted label and actual price delta. This information...