ELKI is an open source (AGPLv3) data mining software written in Java. The focus
of ELKI is research in algorithms, with an emphasis on unsupervised methods in
cluster analysis and outlier detection. In order to achieve high performance and
scalability, ELKI offers data index structures such as the R*-tree that can
provide major performance gains. ELKI is designed to be easy to extend for
researchers and students in this domain, and welcomes contributions of
additional methods. ELKI aims at providing a large collection of highly
parameterizable algorithms, in order to allow easy and fair evaluation and
benchmarking of algorithms.