Author: edwardyoon
Date: Tue Apr 2 05:25:51 2013
New Revision: 1463389
URL: http://svn.apache.org/r1463389
Log:
Minor website updates
Modified:
hama/trunk/src/site/xdoc/getting_started_with_hama.xml
hama/trunk/src/site/xdoc/hama_graph_tutorial.xml
Modified: hama/trunk/src/site/xdoc/getting_started_with_hama.xml
URL:
http://svn.apache.org/viewvc/hama/trunk/src/site/xdoc/getting_started_with_hama.xml?rev=1463389&r1=1463388&r2=1463389&view=diff
==============================================================================
--- hama/trunk/src/site/xdoc/getting_started_with_hama.xml (original)
+++ hama/trunk/src/site/xdoc/getting_started_with_hama.xml Tue Apr 2 05:25:51
2013
@@ -27,7 +27,7 @@ xsi:schemaLocation="http://maven.apache.
<subsection name="Requirements"></subsection>
<p>1. Make sure all required software is installed on all nodes in your
cluster:</p>
<ul>
- <li>hadoop-0.20.x (non-secure version)</li>
+ <li>hadoop-1.0.x or higher version (non-secure version)</li>
<li>Sun Java JDK 1.6.x or higher version</li>
<li>SSH access to manage BSP deamons</li>
</ul>
Modified: hama/trunk/src/site/xdoc/hama_graph_tutorial.xml
URL:
http://svn.apache.org/viewvc/hama/trunk/src/site/xdoc/hama_graph_tutorial.xml?rev=1463389&r1=1463388&r2=1463389&view=diff
==============================================================================
--- hama/trunk/src/site/xdoc/hama_graph_tutorial.xml (original)
+++ hama/trunk/src/site/xdoc/hama_graph_tutorial.xml Tue Apr 2 05:25:51 2013
@@ -41,6 +41,29 @@ xsi:schemaLocation="http://maven.apache.
<p>The user overrides the Compute() method, which will be executed at each
active vertex in every superstep. Predefined Vertex methods allow Compute() to
query information about the current vertex and its edges, and to send messages
to other vertices. Compute() can inspect the value associated with its vertex
via GetValue().</p>
+ <subsection name="VertexReader API"></subsection>
+ <p>You can create your own VertexReader for your data format by exending
org.apache.hama.graph.<b>VertexInputReader</b> class.
+
+ For example, an sequence file contains a linked list of Vertex, can be
parse as following:
+ </p>
+ <pre>
+ public static class PagerankSeqReader
+ extends
+ VertexInputReader<Text, TextArrayWritable, Text, NullWritable,
DoubleWritable> {
+ @Override
+ public boolean parseVertex(Text key, TextArrayWritable value,
+ Vertex<Text, NullWritable, DoubleWritable> vertex) throws
Exception {
+ vertex.setVertexID(key);
+
+ for (Writable v : value.get()) {
+ vertex.addEdge(new Edge<Text, NullWritable>((Text) v, null));
+ }
+
+ return true;
+ }
+ }
+</pre>
+
<subsection name="Example: PageRankVertex"></subsection>
<p>To solve the Page Rank problem using Hama Graph, you can extends the
Vertex class to create a PageRankVertex class.
In this example, the algorithm described Google's Pregel paper was used. The
value of a vertex represents the tentative page rank of the vertex. The graph
is intialized with each vertex value equal to 1/numOfVertices. In each of the
first 30 supersteps, each vertex sends its tentative page rank along all of its
outgoing edges.