[SPARK-13770][DOCUMENTATION][ML] Document the ML feature Interaction

I created Scala and Java example and added documentation.

Author: chie8842 <hayashidac@nttdata.co.jp>

Closes #15658 from hayashidac/SPARK-13770.

(cherry picked from commit ee2e741a)
Signed-off-by: Sean Owen <sowen@cloudera.com>

docs/ml-features.md

@@ -729,6 +729,58 @@ for more details on the API.
 </div>
 </div>
 
+## Interaction
+
+`Interaction` is a `Transformer` which takes vector or double-valued columns, and generates a single vector column that contains the product of all combinations of one value from each input column.
+
+For example, if you have 2 vector type columns each of which has 3 dimensions as input columns, then then you'll get a 9-dimensional vector as the output column.
+
+**Examples**
+
+Assume that we have the following DataFrame with the columns "id1", "vec1", and "vec2":
+
+~~~~
+  id1|vec1          |vec2          
+  ---|--------------|--------------
+  1  |[1.0,2.0,3.0] |[8.0,4.0,5.0] 
+  2  |[4.0,3.0,8.0] |[7.0,9.0,8.0] 
+  3  |[6.0,1.0,9.0] |[2.0,3.0,6.0] 
+  4  |[10.0,8.0,6.0]|[9.0,4.0,5.0] 
+  5  |[9.0,2.0,7.0] |[10.0,7.0,3.0]
+  6  |[1.0,1.0,4.0] |[2.0,8.0,4.0]     
+~~~~
+
+Applying `Interaction` with those input columns,
+then `interactedCol` as the output column contains:
+
+~~~~
+  id1|vec1          |vec2          |interactedCol                                         
+  ---|--------------|--------------|------------------------------------------------------
+  1  |[1.0,2.0,3.0] |[8.0,4.0,5.0] |[8.0,4.0,5.0,16.0,8.0,10.0,24.0,12.0,15.0]            
+  2  |[4.0,3.0,8.0] |[7.0,9.0,8.0] |[56.0,72.0,64.0,42.0,54.0,48.0,112.0,144.0,128.0]     
+  3  |[6.0,1.0,9.0] |[2.0,3.0,6.0] |[36.0,54.0,108.0,6.0,9.0,18.0,54.0,81.0,162.0]        
+  4  |[10.0,8.0,6.0]|[9.0,4.0,5.0] |[360.0,160.0,200.0,288.0,128.0,160.0,216.0,96.0,120.0]
+  5  |[9.0,2.0,7.0] |[10.0,7.0,3.0]|[450.0,315.0,135.0,100.0,70.0,30.0,350.0,245.0,105.0] 
+  6  |[1.0,1.0,4.0] |[2.0,8.0,4.0] |[12.0,48.0,24.0,12.0,48.0,24.0,48.0,192.0,96.0]       
+~~~~
+
+<div class="codetabs">
+<div data-lang="scala" markdown="1">
+
+Refer to the [Interaction Scala docs](api/scala/index.html#org.apache.spark.ml.feature.Interaction)
+for more details on the API.
+
+{% include_example scala/org/apache/spark/examples/ml/InteractionExample.scala %}
+</div>
+
+<div data-lang="java" markdown="1">
+
+Refer to the [Interaction Java docs](api/java/org/apache/spark/ml/feature/Interaction.html)
+for more details on the API.
+
+{% include_example java/org/apache/spark/examples/ml/JavaInteractionExample.java %}
+</div>
+</div>
 
 ## Normalizer
 

examples/src/main/java/org/apache/spark/examples/ml/JavaInteractionExample.java

+/*
+ * 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.ml.feature.Interaction;
+import org.apache.spark.ml.feature.VectorAssembler;
+import org.apache.spark.ml.linalg.Vectors;
+import org.apache.spark.sql.*;
+import org.apache.spark.sql.types.DataTypes;
+import org.apache.spark.sql.types.Metadata;
+import org.apache.spark.sql.types.StructField;
+import org.apache.spark.sql.types.StructType;
+
+import java.util.Arrays;
+import java.util.List;
+
+// $example on$
+// $example off$
+
+public class JavaInteractionExample {
+  public static void main(String[] args) {
+    SparkSession spark = SparkSession
+      .builder()
+      .appName("JavaInteractionExample")
+      .getOrCreate();
+
+    // $example on$
+    List<Row> data = Arrays.asList(
+      RowFactory.create(1, 1, 2, 3, 8, 4, 5),
+      RowFactory.create(2, 4, 3, 8, 7, 9, 8),
+      RowFactory.create(3, 6, 1, 9, 2, 3, 6),
+      RowFactory.create(4, 10, 8, 6, 9, 4, 5),
+      RowFactory.create(5, 9, 2, 7, 10, 7, 3),
+      RowFactory.create(6, 1, 1, 4, 2, 8, 4)
+    );
+    
+    StructType schema = new StructType(new StructField[]{
+      new StructField("id1", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id2", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id3", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id4", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id5", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id6", DataTypes.IntegerType, false, Metadata.empty()),
+      new StructField("id7", DataTypes.IntegerType, false, Metadata.empty())
+    });
+
+    Dataset<Row> df = spark.createDataFrame(data, schema);
+
+    VectorAssembler assembler1 = new VectorAssembler()
+            .setInputCols(new String[]{"id2", "id3", "id4"})
+            .setOutputCol("vec1");
+
+    Dataset<Row> assembled1 = assembler1.transform(df);
+
+    VectorAssembler assembler2 = new VectorAssembler()
+            .setInputCols(new String[]{"id5", "id6", "id7"})
+            .setOutputCol("vec2");
+
+    Dataset<Row> assembled2 = assembler2.transform(assembled1).select("id1", "vec1", "vec2");
+
+    Interaction interaction = new Interaction()
+            .setInputCols(new String[]{"id1","vec1","vec2"})
+            .setOutputCol("interactedCol");
+
+    Dataset<Row> interacted = interaction.transform(assembled2);
+
+    interacted.show(false);
+    // $example off$
+
+    spark.stop();
+  }
+}
+

examples/src/main/scala/org/apache/spark/examples/ml/InteractionExample.scala

+/*
+ * 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
+
+// $example on$
+import org.apache.spark.ml.feature.Interaction
+import org.apache.spark.ml.feature.VectorAssembler
+// $example off$
+import org.apache.spark.sql.SparkSession
+
+object InteractionExample {
+  def main(args: Array[String]): Unit = {
+    val spark = SparkSession
+      .builder
+      .appName("InteractionExample")
+      .getOrCreate()
+
+    // $example on$
+    val df = spark.createDataFrame(Seq(
+      (1, 1, 2, 3, 8, 4, 5),
+      (2, 4, 3, 8, 7, 9, 8),
+      (3, 6, 1, 9, 2, 3, 6),
+      (4, 10, 8, 6, 9, 4, 5),
+      (5, 9, 2, 7, 10, 7, 3),
+      (6, 1, 1, 4, 2, 8, 4)
+    )).toDF("id1", "id2", "id3", "id4", "id5", "id6", "id7")
+
+    val assembler1 = new VectorAssembler().
+      setInputCols(Array("id2", "id3", "id4")).
+      setOutputCol("vec1")
+
+    val assembled1 = assembler1.transform(df)
+
+    val assembler2 = new VectorAssembler().
+      setInputCols(Array("id5", "id6", "id7")).
+      setOutputCol("vec2")
+
+    val assembled2 = assembler2.transform(assembled1).select("id1", "vec1", "vec2")
+
+    val interaction = new Interaction()
+      .setInputCols(Array("id1", "vec1", "vec2"))
+      .setOutputCol("interactedCol")
+
+    val interacted = interaction.transform(assembled2)
+
+    interacted.show(truncate = false)
+    // $example off$
+
+    spark.stop()
+  }
+}
+// scalastyle:on println