From fcafb586f5f4e86c1d263b36a304c4b2d3f06839 Mon Sep 17 00:00:00 2001
From: Adrian Dumascu <adumascu@yahoo.com>
Date: Sun, 25 Aug 2019 06:59:14 -0700
Subject: [PATCH] A few errors discovered while reading the book.

---
 pom.xml                                                       | 2 +-
 src/main/java/com/oreilly/dswj/dataops/MatrixResampler.java   | 4 ----
 src/main/java/com/oreilly/dswj/datasets/Iris.java             | 2 +-
 .../dswj/mapreduce/CustomWordCountMapReduceExample.java       | 3 ++-
 .../java/com/oreilly/dswj/mapreduce/SparseMatrixWritable.java | 2 +-
 5 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/pom.xml b/pom.xml
index f949de3..324c119 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2,7 +2,7 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.oreilly.javabook</groupId>
-    <artifactId>Dava_Science_with_Java</artifactId>
+    <artifactId>Data_Science_with_Java</artifactId>
     <version>1.0-SNAPSHOT</version>
     <packaging>jar</packaging>
     <dependencies>
diff --git a/src/main/java/com/oreilly/dswj/dataops/MatrixResampler.java b/src/main/java/com/oreilly/dswj/dataops/MatrixResampler.java
index 47075a4..26dd0b5 100644
--- a/src/main/java/com/oreilly/dswj/dataops/MatrixResampler.java
+++ b/src/main/java/com/oreilly/dswj/dataops/MatrixResampler.java
@@ -67,10 +67,6 @@ public void calculateTestTrainSplit(double testFraction, long seed) {
         
         Random rnd = new Random(seed);
         
-//        for (int i = 1; i <= features.getRowDimension(); i++) {
-        for (int i = 0; i < features.getRowDimension(); i++) {
-            indeces.add(i);
-        }
         Collections.shuffle(indeces, rnd);
         
         int testSize = new Long(Math.round(testFraction * features.getRowDimension())).intValue();
diff --git a/src/main/java/com/oreilly/dswj/datasets/Iris.java b/src/main/java/com/oreilly/dswj/datasets/Iris.java
index 99da17e..58fbbe3 100644
--- a/src/main/java/com/oreilly/dswj/datasets/Iris.java
+++ b/src/main/java/com/oreilly/dswj/datasets/Iris.java
@@ -64,7 +64,7 @@ public Iris() throws IOException {
                         labels.setEntry(rowCounter, 1, 1);
                         break;
                     case "Iris-virginica":
-                        labels.setEntry(rowCounter, 3, 1);
+                        labels.setEntry(rowCounter, 2, 1);
                         break;
                     default:
                         System.out.println("something wrong with " + plantClass);
diff --git a/src/main/java/com/oreilly/dswj/mapreduce/CustomWordCountMapReduceExample.java b/src/main/java/com/oreilly/dswj/mapreduce/CustomWordCountMapReduceExample.java
index 284612c..3c3c98e 100644
--- a/src/main/java/com/oreilly/dswj/mapreduce/CustomWordCountMapReduceExample.java
+++ b/src/main/java/com/oreilly/dswj/mapreduce/CustomWordCountMapReduceExample.java
@@ -23,6 +23,7 @@
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
 import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
 import org.apache.hadoop.mapreduce.lib.reduce.IntSumReducer;
+import org.apache.hadoop.mapreduce.lib.reduce.LongSumReducer;
 import org.apache.hadoop.util.Tool;
 import org.apache.hadoop.util.ToolRunner;
 
@@ -53,7 +54,7 @@ public int run(String[] args) throws Exception {
         job.setMapperClass(SimpleTokenMapper.class);
         job.setMapOutputKeyClass(Text.class);
         job.setMapOutputValueClass(LongWritable.class);
-        job.setReducerClass(IntSumReducer.class);
+        job.setReducerClass(LongSumReducer.class);
         job.setOutputKeyClass(Text.class);
         job.setOutputValueClass(LongWritable.class);
         job.setNumReduceTasks(1);
diff --git a/src/main/java/com/oreilly/dswj/mapreduce/SparseMatrixWritable.java b/src/main/java/com/oreilly/dswj/mapreduce/SparseMatrixWritable.java
index 0e17b34..4420283 100644
--- a/src/main/java/com/oreilly/dswj/mapreduce/SparseMatrixWritable.java
+++ b/src/main/java/com/oreilly/dswj/mapreduce/SparseMatrixWritable.java
@@ -40,7 +40,7 @@ public SparseMatrixWritable(int rowIndex, int columnIndex, double entry) {
     @Override
     public void write(DataOutput d) throws IOException {
         d.writeInt(rowIndex);
-        d.writeInt(rowIndex);
+        d.writeInt(columnIndex);
         d.writeDouble(entry);
     }