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README.md

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+PH-Tree add-on for ELKI
+=======================
+
+This is an extension for the
+[ELKI Data Mining Toolkit](http://elki.dbs.ifi.lmu.de/)
+to use the PH-tree index.
+
+* [ELKI on GitHub](https://github.com/elki-project/elki/)
+* [PH-Tree on GitHub](https://github.com/tzaeschke/phtree)
+
+Usage
+-----
+
+Build the package using Maven `mvn package`, then add the resulting
+`target/elki-phtree-1.0.jar` to your ELKI class path.
+
+To use the ph-tree, set the `-db.index` parameter to
+`tree.spatial.ph.MemoryPHTree` and use an algorithm using
+Euclidean distance (other Minkowski norms and squared Euclidean distance are
+also supported), and either radius or k-nearest-neighbor queries.
+
+About the PH-Tree
+-----------------
+
+The PH-tree is a multi-dimensional indexing and storage structure.
+By default it stores k-dimensional keys (points) consisting of k 64bit-integers. However, it can also be used
+to efficiently store floating point values or k-dimensional rectangles.
+It supports kNN queries, range queries, window queries and fast update/moving of individual entries.
+
+The PH-tree was developed at ETH Zurich and first published in:
+"The PH-Tree: A Space-Efficient Storage Structure and Multi-Dimensional Index" ([PDF](http://globis.ethz.ch/?pubdownload=699)), 
+Tilmann Zäschke, Christoph Zimmerli and Moira C. Norrie, 
+Proceedings of Intl. Conf. on Management of Data (SIGMOD), 2014
+
+The current version of the PH-tree is discussed in more detail here: ([PDF](https://github.com/tzaeschke/phtree/blob/master/PhTreeRevisited.pdf)) (2015).
+
+Contact:
+{zaeschke,zimmerli,norrie)@inf.ethz.ch
+