# Run a program to estimate pi

### Run a program to estimate PI, which is 3.14592…

First Scala code with Apache Spark using Eclipse IDE

Start Eclipse Scala Plug-ins, click New->Scala Project

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Enter Spark, click Finish

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Right click Project name spark you just created, click New->Package

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Enter the name of Package: using reverse domain name, like below, click Finish

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Right mouse click Package name, select New->Scala Object, enter reverse domain name+name of object which is pi in this instance, click Finish

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Copy below code after the package line, in my example, “package com.jentekco.spark”

```
import scala.math.random
import org.apache.spark._
import org.apache.log4j._
import org.apache.spark.sql.SparkSession
object pi {
    def main(args: Array[String]): Unit = {
    Logger.getLogger("org").setLevel(Level.ERROR)
    val spark = SparkSession
      .builder
      .master("local")
      .appName("Spark Pi")
      .getOrCreate()
    val slices = if (args.length > 0) args(0).toInt else 2
    val n = math.min(100000L * slices, Int.MaxValue).toInt // avoid overflow
    val count = spark.sparkContext.parallelize(1 until n, slices).map { i =>
      val x = random * 2 - 1
      val y = random * 2 - 1
      if (x*x + y*y <= 1) 1 else 0
    }.reduce(_ + _)
    println(s"Pi is roughly ${4.0 * count / (n - 1)}")
    spark.stop()
  } }
```

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To fix it, right click project spark, choose Properties,

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Choose Java Build Path->Add External JARS

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Navigate to the SPARK Home folder, jars sub folder, select all jar files, then click Open

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Then the errors go away, Scala code is compiled successfully.

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To run the Scala pi program, click Run->Run Configuration.&#x20;

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Then click Java Application (Scala is Java at the end of day)

In the Name field, enter pi

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in the Project field, enter Spark, in the Main class field, in my example, I enter com.jentekco.spark.pi, then click Run

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See output in the Console: “Pi is roughly 3.144195720978605”

Now that you have done your development and test of the scala project, you need to make a jar file to be deployed to the production. Right mouse click on spark, select Export

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Choose JAR file and click Next

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Under the resource to export, select the right project, in this case, spark

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Choose proper folder to export pi.jar using Browse button, click Finish when done

You can run it on your PC which already has spark home, using spark-submit:

```
%SPARK_HOME%\bin\spark-submit --class com.jentekco.spark.pi pi.jar
```

Pi is roughly 3.14279571397857