diff --git a/graphx/src/main/scala/org/apache/spark/graphx/EdgeRDD.scala b/graphx/src/main/scala/org/apache/spark/graphx/EdgeRDD.scala
index 7fd65806268df8282a287c88c3f4b95f578cc46c..d1d9703159e797f1b12b85d68e98f65160487e5c 100644
--- a/graphx/src/main/scala/org/apache/spark/graphx/EdgeRDD.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/EdgeRDD.scala
@@ -7,7 +7,10 @@ import org.apache.spark.graphx.impl.EdgePartition
import org.apache.spark.rdd.RDD
import org.apache.spark.storage.StorageLevel
-
+/**
+ * `EdgeRDD[ED]` extends `RDD[Edge[ED]]` by storing the edges in columnar format on each partition
+ * for performance. It is constructed using [[org.apache.spark.graphx.impl.EdgePartitionBuilder]].
+ */
class EdgeRDD[@specialized ED: ClassTag](
val partitionsRDD: RDD[(PartitionID, EdgePartition[ED])])
extends RDD[Edge[ED]](partitionsRDD.context, List(new OneToOneDependency(partitionsRDD))) {
diff --git a/graphx/src/main/scala/org/apache/spark/graphx/Graph.scala b/graphx/src/main/scala/org/apache/spark/graphx/Graph.scala
index 6f2d19d0dab8f096973f74fc37d05f0421833ad3..aeeaddb3208bfeaac050155ce8fed1936e5e922b 100644
--- a/graphx/src/main/scala/org/apache/spark/graphx/Graph.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/Graph.scala
@@ -15,12 +15,9 @@ import org.apache.spark.storage.StorageLevel
* RDDs, the graph is a functional data-structure in which mutating
* operations return new graphs.
*
- * @see GraphOps for additional graph member functions.
- *
- * @note The majority of the graph operations are implemented in
- * `GraphOps`. All the convenience operations are defined in the
- * `GraphOps` class which may be shared across multiple graph
- * implementations.
+ * @note [[org.apache.spark.graphx.GraphOps]] contains additional convenience operations.
+ * [[org.apache.spark.graphx.algorithms.Algorithms]] contains graph algorithms; to access these,
+ * import `org.apache.spark.graphx.algorithms._`.
*
* @tparam VD the vertex attribute type
* @tparam ED the edge attribute type
@@ -32,9 +29,6 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
*
* @note vertex ids are unique.
* @return An RDD containing the vertices in this graph
- *
- * @see Vertex for the vertex type.
- *
*/
val vertices: VertexRDD[VD]
@@ -45,8 +39,8 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
*
* @return An RDD containing the edges in this graph
*
- * @see Edge for the edge type.
- * @see edgesWithVertices to get an RDD which contains all the edges
+ * @see [[org.apache.spark.graphx.Edge]] for the edge type.
+ * @see `triplets` to get an RDD which contains all the edges
* along with their vertex data.
*
*/
@@ -64,11 +58,10 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* {{{
* type Color = Int
* val graph: Graph[Color, Int] = Graph.textFile("hdfs://file.tsv")
- * val numInvalid = graph.edgesWithVertices()
- * .map(e => if (e.src.data == e.dst.data) 1 else 0).sum
+ * val numInvalid = graph.triplets.map(e => if (e.src.data == e.dst.data) 1 else 0).sum
* }}}
*
- * @see edges() If only the edge data and adjacent vertex ids are
+ * @see `edges` if only the edge data and adjacent vertex ids are
* required.
*
*/
@@ -88,19 +81,19 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* Return a graph that is cached when first created. This is used to
* pin a graph in memory enabling multiple queries to reuse the same
* construction process.
- *
- * @see RDD.cache() for a more detailed explanation of caching.
*/
def cache(): Graph[VD, ED]
/**
- * Uncache only the vertices of this graph, leaving the edges alone. This is useful because most
- * graph operations modify the vertices but reuse the edges.
+ * Uncache only the vertices of this graph, leaving the edges alone. This is useful in iterative
+ * algorithms that modify the vertex attributes but reuse the edges. This method can be used to
+ * uncache the vertex attributes of previous iterations once they are no longer needed, improving
+ * GC performance.
*/
def unpersistVertices(blocking: Boolean = true): Graph[VD, ED]
/**
- * Repartition the edges in the graph according to partitionStrategy.
+ * Repartition the edges in the graph according to `partitionStrategy`.
*/
def partitionBy(partitionStrategy: PartitionStrategy): Graph[VD, ED]
@@ -113,8 +106,7 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* Construct a new graph where each vertex value has been
* transformed by the map function.
*
- * @note This graph is not changed and that the new graph has the
- * same structure. As a consequence the underlying index structures
+ * @note The new graph has the same structure. As a consequence the underlying index structures
* can be reused.
*
* @param map the function from a vertex object to a new vertex value.
@@ -126,8 +118,7 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* {{{
* val rawGraph: Graph[(), ()] = Graph.textFile("hdfs://file")
* val root = 42
- * var bfsGraph = rawGraph
- * .mapVertices[Int]((vid, data) => if (vid == root) 0 else Math.MaxValue)
+ * var bfsGraph = rawGraph.mapVertices[Int]((vid, data) => if (vid == root) 0 else Math.MaxValue)
* }}}
*
*/
@@ -137,7 +128,7 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* Construct a new graph where the value of each edge is
* transformed by the map operation. This function is not passed
* the vertex value for the vertices adjacent to the edge. If
- * vertex values are desired use the mapTriplets function.
+ * vertex values are desired, use the `mapTriplets` method.
*
* @note This graph is not changed and that the new graph has the
* same structure. As a consequence the underlying index structures
@@ -156,15 +147,13 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
}
/**
- * Construct a new graph transforming the value of each edge using
- * the user defined iterator transform. The iterator transform is
- * given an iterator over edge triplets within a logical partition
- * and should yield a new iterator over the new values of each edge
- * in the order in which they are provided to the iterator transform
- * If adjacent vertex values are not required, consider using the
- * mapEdges function instead.
+ * Construct a new graph transforming the value of each edge using the user defined iterator
+ * transform. The iterator transform is given an iterator over edges within a logical partition
+ * as well as the partition's ID, and it should return a new iterator over the new values of each
+ * edge. The new iterator's elements must correspond one-to-one with the old iterator's
+ * elements. If adjacent vertex values are desired, use the `mapTriplets` method.
*
- * @note This that this does not change the structure of the
+ * @note This does not change the structure of the
* graph or modify the values of this graph. As a consequence
* the underlying index structures can be reused.
*
@@ -183,9 +172,9 @@ abstract class Graph[VD: ClassTag, ED: ClassTag] {
* transformed by the map operation. This function passes vertex
* values for the adjacent vertices to the map function. If
* adjacent vertex values are not required, consider using the
- * mapEdges function instead.
+ * `mapEdges` method instead.
*
- * @note This that this does not change the structure of the
+ * @note This does not change the structure of the
* graph or modify the values of this graph. As a consequence
* the underlying index structures can be reused.
*