< Initalization algorithm.
< Centers
< Verbosity level.
< Data type.
< Clustring algorithm.
< Centers inter-distances.
< Current solution energy.
< Maximum number of comparisons when using ANN-kmeans.
< Number of trees in forest when using ANN-kmeans.
< Distance.
< Maximum number of refinement iterations.
< Data dimensionality.
< Minimum energy variation.
< Number of centers.
< Number of clustering repetitions.