Default constructor is provided to support serialization
Default constructor is provided to support serialization
Caches the vertices and edges associated with this graph.
An RDD containing the edges and their associated attributes.
An RDD containing the edges and their associated attributes. The entries in the RDD contain just the source id and target id along with the edge data.
an RDD containing the edges in this graph
Merges multiple edges between two vertices into a single edge.
Merges multiple edges between two vertices into a single edge. For correct results, the graph must have been partitioned using partitionBy.
the user-supplied commutative associative function to merge edge attributes for duplicate edges.
The resulting graph with a single edge for each (source, dest) vertex pair.
Transforms each edge attribute using the map function, passing it a whole partition at a time.
Transforms each edge attribute using the map function, passing it a whole partition at a
time. The map function 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 mapTriplets
.
the new edge data type
Transforms each edge attribute in the graph using the map function.
Transforms each edge attribute in the graph using the map function. The map function is not
passed the vertex value for the vertices adjacent to the edge. If vertex values are desired,
use mapTriplets
.
the new edge data type
the function from an edge object to a new edge value.
This function might be used to initialize edge attributes.
This graph is not changed and that the new graph has the same structure. As a consequence the underlying index structures can be reused.
Aggregates values from the neighboring edges and vertices of each vertex.
Aggregates values from the neighboring edges and vertices of each vertex. The user supplied
mapFunc
function is invoked on each edge of the graph, generating 0 or more "messages" to be
"sent" to either vertex in the edge. The reduceFunc
is then used to combine the output of
the map phase destined to each vertex.
the type of "message" to be sent to each vertex
the user defined map function which returns 0 or more messages to neighboring vertices
the user defined reduce function which should be commutative and associative and is used to combine the output of the map phase
optionally, a set of "active" vertices and a direction of edges to consider
when running mapFunc
. If the direction is In
, mapFunc
will only be run on edges with
destination in the active set. If the direction is Out
, mapFunc
will only be run on edges
originating from vertices in the active set. If the direction is Either
, mapFunc
will be
run on edges with *either* vertex in the active set. If the direction is Both
, mapFunc
will
be run on edges with *both* vertices in the active set. The active set must have the same index
as the graph's vertices.
We can use this function to compute the in-degree of each vertex
val rawGraph: Graph[(),()] = Graph.textFile("twittergraph") val inDeg: RDD[(VertexId, Int)] = mapReduceTriplets[Int](et => Iterator((et.dst.id, 1)), _ + _)
By expressing computation at the edge level we achieve maximum parallelism. This is one of the core functions in the Graph API in that enables neighborhood level computation. For example this function can be used to count neighbors satisfying a predicate or implement PageRank.
Transforms each edge attribute a partition at a time using the map function, passing it the adjacent vertex attributes as well.
Transforms each edge attribute a partition at a time using the map function, passing it the
adjacent vertex attributes as well. The map function 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. If adjacent vertex values are not required, consider
using mapEdges
instead.
the new edge data type
Transforms each edge attribute using the map function, passing it the adjacent vertex attributes as well.
Transforms each edge attribute using the map function, passing it the adjacent vertex attributes
as well. If adjacent vertex values are not required, consider using mapEdges
instead.
the new edge data type
the function from an edge object to a new edge value.
This function might be used to initialize edge attributes based on the attributes associated with each vertex.
val rawGraph: Graph[Int, Int] = someLoadFunction() val graph = rawGraph.mapTriplets[Int]( edge => edge.src.data - edge.dst.data)
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.
Transforms each vertex attribute in the graph using the map function.
Transforms each vertex attribute in the graph using the map function.
the new vertex data type
We might use this operation to change the vertex values from one type to another to initialize an algorithm.
val rawGraph: Graph[(), ()] = Graph.textFile("hdfs://file") val root = 42 var bfsGraph = rawGraph.mapVertices[Int]((vid, data) => if (vid == root) 0 else Math.MaxValue)
The new graph has the same structure. As a consequence the underlying index structures can be reused.
Restricts the graph to only the vertices and edges that are also in other
, but keeps the
attributes from this graph.
Restricts the graph to only the vertices and edges that are also in other
, but keeps the
attributes from this graph.
the graph to project this graph onto
a graph with vertices and edges that exist in both the current graph and other
,
with vertex and edge data from the current graph
The associated GraphOps object.
Joins the vertices with entries in the table
RDD and merges the results using mapFunc
.
Joins the vertices with entries in the table
RDD and merges the results using mapFunc
. The
input table should contain at most one entry for each vertex. If no entry in other
is
provided for a particular vertex in the graph, the map function receives None
.
the type of entry in the table of updates
the new vertex value type
the table to join with the vertices in the graph. The table should contain at most one entry for each vertex.
This function is used to update the vertices with new values based on external data. For example we could add the out-degree to each vertex record:
val rawGraph: Graph[_, _] = Graph.textFile("webgraph") val outDeg: RDD[(VertexId, Int)] = rawGraph.outDegrees() val graph = rawGraph.outerJoinVertices(outDeg) { (vid, data, optDeg) => optDeg.getOrElse(0) }
Repartitions the edges in the graph according to partitionStrategy
.
Caches the vertices and edges associated with this graph at the specified storage level.
Reverses all edges in the graph.
Restricts the graph to only the vertices and edges satisfying the predicates.
Restricts the graph to only the vertices and edges satisfying the predicates. The resulting subgraph satisifies
V' = {v : for all v in V where vpred(v)} E' = {(u,v): for all (u,v) in E where epred((u,v)) && vpred(u) && vpred(v)}
the edge predicate, which takes a triplet and evaluates to true if the edge is to remain in the subgraph. Note that only edges where both vertices satisfy the vertex predicate are considered.
the vertex predicate, which takes a vertex object and evaluates to true if the vertex is to be included in the subgraph
the subgraph containing only the vertices and edges that satisfy the predicates
Return a RDD that brings edges together with their source and destination vertices.
Uncaches only the vertices of this graph, leaving the edges alone.
Uncaches 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.
An RDD containing the vertices and their associated attributes.
A graph that supports computation on graphs.
Graphs are represented using two classes of data: vertex-partitioned and edge-partitioned.
vertices
contains vertex attributes, which are vertex-partitioned.edges
contains edge attributes, which are edge-partitioned. For operations on vertex neighborhoods, vertex attributes are replicated to the edge partitions where they appear as sources or destinations.routingTable
stores the routing information for shipping vertex attributes to edge partitions.replicatedVertexView
stores a view of the replicated vertex attributes created using the routing table.