[SPARK-10669] [DOCS] Link to each language's API in codetabs in ML docs: spark.mllib

In the Markdown docs for the spark.mllib Programming Guide, we have code examples with codetabs for each language. We should link to each language's API docs within the corresponding codetab, but we are inconsistent about this. For an example of what we want to do, see the "ChiSqSelector" section in https://github.com/apache/spark/blob/64743870f23bffb8d96dcc8a0181c1452782a151/docs/mllib-feature-extraction.md
This JIRA is just for spark.mllib, not spark.ml.

Please let me know if more work is needed, thanks a lot.

Author: Xin Ren <iamshrek@126.com>

Closes #8977 from keypointt/SPARK-10669.

1 files changed, 37 insertions, 10 deletions

diff --git a/docs/mllib-feature-extraction.md b/docs/mllib-feature-extraction.md
index 7e417ed5f3..5bee170c61 100644
--- a/docs/mllib-feature-extraction.md
+++ b/docs/mllib-feature-extraction.md
@@ -56,6 +56,9 @@ and [IDF](api/scala/index.html#org.apache.spark.mllib.feature.IDF).
 `HashingTF` takes an `RDD[Iterable[_]]` as the input.
 Each record could be an iterable of strings or other types.
 
+Refer to the [`HashingTF` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.HashingTF) for details on the API.
+
+
 {% highlight scala %}
 import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext
@@ -103,6 +106,9 @@ and [IDF](api/python/pyspark.mllib.html#pyspark.mllib.feature.IDF).
 `HashingTF` takes an RDD of list as the input.
 Each record could be an iterable of strings or other types.
 
+
+Refer to the [`HashingTF` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.feature.HashingTF) for details on the API.
+
 {% highlight python %}
 from pyspark import SparkContext
 from pyspark.mllib.feature import HashingTF
@@ -183,7 +189,9 @@ the [text8](http://mattmahoney.net/dc/text8.zip) data and extract it to your pre
 Here we assume the extracted file is `text8` and in same directory as you run the spark shell.  
 
 <div class="codetabs">
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`Word2Vec` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.Word2Vec) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark._
 import org.apache.spark.rdd._
@@ -207,7 +215,9 @@ model.save(sc, "myModelPath")
 val sameModel = Word2VecModel.load(sc, "myModelPath")
 {% endhighlight %}
 </div>
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`Word2Vec` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.feature.Word2Vec) for more details on the API.
+
 {% highlight python %}
 from pyspark import SparkContext
 from pyspark.mllib.feature import Word2Vec
@@ -264,7 +274,9 @@ The example below demonstrates how to load a dataset in libsvm format, and stand
 so that the new features have unit standard deviation and/or zero mean.
 
 <div class="codetabs">
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`StandardScaler` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.StandardScaler) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.feature.StandardScaler
@@ -288,7 +300,9 @@ val data2 = data.map(x => (x.label, scaler2.transform(Vectors.dense(x.features.t
 {% endhighlight %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`StandardScaler` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.feature.StandardScaler) for more details on the API.
+
 {% highlight python %}
 from pyspark.mllib.util import MLUtils
 from pyspark.mllib.linalg import Vectors
@@ -338,7 +352,9 @@ The example below demonstrates how to load a dataset in libsvm format, and norma
 with $L^2$ norm, and $L^\infty$ norm.
 
 <div class="codetabs">
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`Normalizer` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.Normalizer) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.feature.Normalizer
@@ -358,7 +374,9 @@ val data2 = data.map(x => (x.label, normalizer2.transform(x.features)))
 {% endhighlight %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`Normalizer` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.feature.Normalizer) for more details on the API.
+
 {% highlight python %}
 from pyspark.mllib.util import MLUtils
 from pyspark.mllib.linalg import Vectors
@@ -532,7 +550,10 @@ v_N
 This example below demonstrates how to transform vectors using a transforming vector value.
 
 <div class="codetabs">
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+
+Refer to the [`ElementwiseProduct` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.ElementwiseProduct) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.feature.ElementwiseProduct
@@ -551,7 +572,9 @@ val transformedData2 = data.map(x => transformer.transform(x))
 {% endhighlight %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
+Refer to the [`ElementwiseProduct` Java docs](api/java/org/apache/spark/mllib/feature/ElementwiseProduct.html) for details on the API.
+
 {% highlight java %}
 import java.util.Arrays;
 import org.apache.spark.api.java.JavaRDD;
@@ -580,7 +603,9 @@ JavaRDD<Vector> transformedData2 = data.map(
 {% endhighlight %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`ElementwiseProduct` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.feature.ElementwiseProduct) for more details on the API.
+
 {% highlight python %}
 from pyspark import SparkContext
 from pyspark.mllib.linalg import Vectors
@@ -617,7 +642,9 @@ and use them to project the vectors into a low-dimensional space while keeping a
 for calculation a [Linear Regression]((mllib-linear-methods.html))
 
 <div class="codetabs">
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`PCA` Scala docs](api/scala/index.html#org.apache.spark.mllib.feature.PCA) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.mllib.regression.LinearRegressionWithSGD
 import org.apache.spark.mllib.regression.LabeledPoint