Github user thvasilo commented on a diff in the pull request: https://github.com/apache/flink/pull/792#discussion_r32197679 --- Diff: docs/libs/ml/quickstart.md --- @@ -24,4 +25,214 @@ under the License. * This will be replaced by the TOC {:toc} -Coming soon. +## Introduction + +FlinkML is designed to make learning from your data a straight-forward process, abstracting away +the complexities that usually come with having to deal with big data learning tasks. In this +quick-start guide we will show just how easy it is to solve a simple supervised learning problem +using FlinkML. But first some basics, feel free to skip the next few lines if you're already +familiar with Machine Learning (ML). + +As defined by Murphy [1] ML deals with detecting patterns in data, and using those +learned patterns to make predictions about the future. We can categorize most ML algorithms into +two major categories: Supervised and Unsupervised Learning. + +* **Supervised Learning** deals with learning a function (mapping) from a set of inputs +(features) to a set of outputs. The learning is done using a *training set* of (input, +output) pairs that we use to approximate the mapping function. Supervised learning problems are +further divided into classification and regression problems. In classification problems we try to +predict the *class* that an example belongs to, for example whether a user is going to click on +an ad or not. Regression problems one the other hand, are about predicting (real) numerical +values, often called the dependent variable, for example what the temperature will be tomorrow. + +* **Unsupervised Learning** deals with discovering patterns and regularities in the data. An example +of this would be *clustering*, where we try to discover groupings of the data from the +descriptive features. Unsupervised learning can also be used for feature selection, for example +through [principal components analysis](https://en.wikipedia.org/wiki/Principal_component_analysis). + +## Linking with FlinkML + +In order to use FlinkML in you project, first you have to +[set up a Flink program](http://ci.apache.org/projects/flink/flink-docs-master/apis/programming_guide.html#linking-with-flink). +Next, you have to add the FlinkML dependency to the `pom.xml` of your project: + +{% highlight xml %} +<dependency> + <groupId>org.apache.flink</groupId> + <artifactId>flink-ml</artifactId> + <version>{{site.version }}</version> +</dependency> +{% endhighlight %} + +## Loading data + +To load data to be used with FlinkML we can use the ETL capabilities of Flink, or specialized +functions for formatted data, such as the LibSVM format. For supervised learning problems it is +common to use the `LabeledVector` class to represent the `(features, label)` examples. A `LabeledVector` +object will have a FlinkML `Vector` member representing the features of the example and a `Double` +member which represents the label, which could be the class in a classification problem, or the dependent +variable for a regression problem. + +As an example, we can use Haberman's Survival Data Set , which you can +[download from the UCI ML repository](http://archive.ics.uci.edu/ml/machine-learning-databases/haberman/haberman.data. +This dataset *"contains cases from study conducted on the survival of patients who had undergone +surgery for breast cancer"*. The data comes in a comma-separated file, where the first 3 columns +are the features and last column is the class, and the 4th column indicates whether the patient +survived 5 years or longer (label 1), or died within 5 years (label 2). You can check the [UCI +page](https://archive.ics.uci.edu/ml/datasets/Haberman%27s+Survival) for more information on the data. + +We can load the data as a `DataSet[String]` first: + +{% highlight scala %} + +import org.apache.flink.api.scala.ExecutionEnvironment + +val env = ExecutionEnvironment.createLocalEnvironment(2) --- End diff -- Good idea, I will use that instead.
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