From 0b713e0455d01999d5a027ddc2ea8527eb085b34 Mon Sep 17 00:00:00 2001
From: Yuhao Yang <hhbyyh@gmail.com>
Date: Fri, 11 Mar 2016 09:31:35 +0200
Subject: [PATCH] [SPARK-13512][ML] add example and doc for MaxAbsScaler
## What changes were proposed in this pull request?
jira: https://issues.apache.org/jira/browse/SPARK-13512
Add example and doc for ml.feature.MaxAbsScaler.
## How was this patch tested?
unit tests
Author: Yuhao Yang <hhbyyh@gmail.com>
Closes #11392 from hhbyyh/maxabsdoc.
---
docs/ml-features.md | 32 ++++++++++++
.../examples/ml/JavaMaxAbsScalerExample.java | 52 +++++++++++++++++++
.../examples/ml/MaxAbsScalerExample.scala | 49 +++++++++++++++++
3 files changed, 133 insertions(+)
create mode 100644 examples/src/main/java/org/apache/spark/examples/ml/JavaMaxAbsScalerExample.java
create mode 100644 examples/src/main/scala/org/apache/spark/examples/ml/MaxAbsScalerExample.scala
diff --git a/docs/ml-features.md b/docs/ml-features.md
index 68d3ea2971..4fe8eefc26 100644
--- a/docs/ml-features.md
+++ b/docs/ml-features.md
@@ -773,6 +773,38 @@ for more details on the API.
</div>
</div>
+
+## MaxAbsScaler
+
+`MaxAbsScaler` transforms a dataset of `Vector` rows, rescaling each feature to range [-1, 1]
+by dividing through the maximum absolute value in each feature. It does not shift/center the
+data, and thus does not destroy any sparsity.
+
+`MaxAbsScaler` computes summary statistics on a data set and produces a `MaxAbsScalerModel`. The
+model can then transform each feature individually to range [-1, 1].
+
+The following example demonstrates how to load a dataset in libsvm format and then rescale each feature to [-1, 1].
+
+<div class="codetabs">
+<div data-lang="scala" markdown="1">
+
+Refer to the [MaxAbsScaler Scala docs](api/scala/index.html#org.apache.spark.ml.feature.MaxAbsScaler)
+and the [MaxAbsScalerModel Scala docs](api/scala/index.html#org.apache.spark.ml.feature.MaxAbsScalerModel)
+for more details on the API.
+
+{% include_example scala/org/apache/spark/examples/ml/MaxAbsScalerExample.scala %}
+</div>
+
+<div data-lang="java" markdown="1">
+
+Refer to the [MaxAbsScaler Java docs](api/java/org/apache/spark/ml/feature/MaxAbsScaler.html)
+and the [MaxAbsScalerModel Java docs](api/java/org/apache/spark/ml/feature/MaxAbsScalerModel.html)
+for more details on the API.
+
+{% include_example java/org/apache/spark/examples/ml/JavaMaxAbsScalerExample.java %}
+</div>
+</div>
+
## Bucketizer
`Bucketizer` transforms a column of continuous features to a column of feature buckets, where the buckets are specified by users. It takes a parameter:
diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaMaxAbsScalerExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaMaxAbsScalerExample.java
new file mode 100644
index 0000000000..b1e3b9137f
--- /dev/null
+++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaMaxAbsScalerExample.java
@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.examples.ml;
+
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaSparkContext;
+// $example on$
+import org.apache.spark.ml.feature.MaxAbsScaler;
+import org.apache.spark.ml.feature.MaxAbsScalerModel;
+import org.apache.spark.sql.DataFrame;
+// $example off$
+import org.apache.spark.sql.SQLContext;
+
+public class JavaMaxAbsScalerExample {
+
+ public static void main(String[] args) {
+ SparkConf conf = new SparkConf().setAppName("JavaMaxAbsScalerExample");
+ JavaSparkContext jsc = new JavaSparkContext(conf);
+ SQLContext jsql = new SQLContext(jsc);
+
+ // $example on$
+ DataFrame dataFrame = jsql.read().format("libsvm").load("data/mllib/sample_libsvm_data.txt");
+ MaxAbsScaler scaler = new MaxAbsScaler()
+ .setInputCol("features")
+ .setOutputCol("scaledFeatures");
+
+ // Compute summary statistics and generate MaxAbsScalerModel
+ MaxAbsScalerModel scalerModel = scaler.fit(dataFrame);
+
+ // rescale each feature to range [-1, 1].
+ DataFrame scaledData = scalerModel.transform(dataFrame);
+ scaledData.show();
+ // $example off$
+ jsc.stop();
+ }
+
+}
diff --git a/examples/src/main/scala/org/apache/spark/examples/ml/MaxAbsScalerExample.scala b/examples/src/main/scala/org/apache/spark/examples/ml/MaxAbsScalerExample.scala
new file mode 100644
index 0000000000..aafb5efd69
--- /dev/null
+++ b/examples/src/main/scala/org/apache/spark/examples/ml/MaxAbsScalerExample.scala
@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// scalastyle:off println
+package org.apache.spark.examples.ml
+
+import org.apache.spark.{SparkConf, SparkContext}
+// $example on$
+import org.apache.spark.ml.feature.MaxAbsScaler
+// $example off$
+import org.apache.spark.sql.SQLContext
+
+object MaxAbsScalerExample {
+ def main(args: Array[String]): Unit = {
+ val conf = new SparkConf().setAppName("MaxAbsScalerExample")
+ val sc = new SparkContext(conf)
+ val sqlContext = new SQLContext(sc)
+
+ // $example on$
+ val dataFrame = sqlContext.read.format("libsvm").load("data/mllib/sample_libsvm_data.txt")
+ val scaler = new MaxAbsScaler()
+ .setInputCol("features")
+ .setOutputCol("scaledFeatures")
+
+ // Compute summary statistics and generate MaxAbsScalerModel
+ val scalerModel = scaler.fit(dataFrame)
+
+ // rescale each feature to range [-1, 1]
+ val scaledData = scalerModel.transform(dataFrame)
+ scaledData.show()
+ // $example off$
+ sc.stop()
+ }
+}
+// scalastyle:on println
--
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