ELKI DBSCAN R* tree index

Question

In MiniGUi, I can see db.index. How do I set it to tree.spatial.rstarvariants.rstar.RStartTreeFactory via Java code?

I have implemented:

params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,tree.spatial.rstarvariants.rstar.RStarTreeFactory);

For the second parameter of addParameter() function tree.spatial...RStarTreeFactory class not found

// Setup parameters:
            ListParameterization params = new ListParameterization();
            params.addParameter(
                    FileBasedDatabaseConnection.Parameterizer.INPUT_ID,
                    fileLocation);
            params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,
                RStarTreeFactory.class);

I am getting NullPointerException. Did I use RStarTreeFactory.class correctly?

Answer 1

The ELKI command line (and MiniGui; which is a command line builder) allow to specify shorthand class names, leaving out the package prefix of the implemented interface.

The full command line documentation yields:

-db.index <object_1|class_1,...,object_n|class_n>
    Database indexes to add.
    Implementing de.lmu.ifi.dbs.elki.index.IndexFactory
    Known classes (default package de.lmu.ifi.dbs.elki.index.):
    -> tree.spatial.rstarvariants.rstar.RStarTreeFactory
    -> ...

I.e. for this parameter, the class prefix de.lmu.ifi.dbs.elki.index. may be omitted.

The full class name thus is:

de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.rstar.RStarTreeFactory

or you just type RStarTreeFactory, and let eclipse auto-repair the import:

params.addParameter(AbstractDatabase.Parameterizer.INDEX_ID,
    RStarTreeFactory.class);
// Bulk loading static data yields much better trees and is much faster, too.
params.addParameter(RStarTreeFactory.Parameterizer.BULK_SPLIT_ID, 
    SortTileRecursiveBulkSplit.class);
// Page size should fit your dimensionality.
// For 2-dimensional data, use page sizes less than 1000.
// Rule of thumb: 15...20 * (dim * 8 + 4) is usually reasonable
// (for in-memory bulk-loaded trees)
params.addParameter(AbstractPageFileFactory.Parameterizer.PAGE_SIZE_ID, 300);

See also: Geo Indexing example in the tutorial folder.