## Details

## Description

Hi,

my name is Christoph Nagel. I'm student on technical university Berlin and participating on the course of Isabel Drost and Sebastian Schelter.

My work is to implement the pagerank-algorithm, where the pagerank-vector fits in memory.

For the computation I used the naive algorithm shown in the book 'Mining of Massive Datasets' from Rajaraman & Ullman (http://www-scf.usc.edu/~csci572/2012Spring/UllmanMiningMassiveDataSets.pdf).

Matrix- and vector-multiplication are done with mahout methods.

Most work is the transformation the input graph, which has to consists of a nodes- and edges file.

Format of nodes file: <node>\n

Format of edges file: <startNode>\t<endNode>\n

Therefore I created the following classes:

- LineIndexer: assigns each line an index
- EdgesToIndex: indexes the nodes of the edges
- EdgesIndexToTransitionMatrix: creates the transition matrix
- Pagerank: computes PR from transition matrix
- JoinNodesWithPagerank: creates the joined output
- PagerankExampleJob: does the complete job

Each class has a test (not PagerankExampleJob) and I took the example of the book for evaluating.

## Activity

Field | Original Value | New Value |
---|---|---|

Attachment | MAHOUT-742.patch [ 12483458 ] |

Status | Open [ 1 ] | Patch Available [ 10002 ] |

Fix Version/s | 0.6 [ 12316364 ] |

Status | Patch Available [ 10002 ] | Resolved [ 5 ] |

Assignee | Sebastian Schelter [ ssc ] | |

Resolution | Fixed [ 1 ] |

Status | Resolved [ 5 ] | Closed [ 6 ] |

Thank you very much for your great work, Christoph!

Unfortunately we have to clarify whether we are legally allowed to include a pagerank implementation before we can commit your contribution...