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data-miningoutlierselki

Top n outliers in ResultWriter

I am dealing with high dimensional and large dataset, so i need to get just Top N outliers from output of ResultWriter. There is some option in elki to get just the top N outliers from this output?

Solution

  • The ResultWriter is some of the oldest code in ELKI, and needs to be rewritten. It's rather generic - it tries to figure out how to best serialize output as text.

    If you want some specific format, or a specific subset, the proper way is to write your own ResultHandler. There is a tutorial for writing a ResultHandler.

    If you want to find the input coordinates in the result,

    Database db = ResultUtil.findDatabase(baseResult);
Relation<NumberVector> rel = db.getRelation(TypeUtil.NUMBER_VECTOR_VARIABLE_LENGTH);

    will return the first relation containing numeric vectors.

    To iterate over the objects sorted by their outlier score, use:

    OrderingResult order = outlierResult.getOrdering();
DBIDs ids = order.order(order.getDBIDs());
for (DBIDIter it = ids.iter(); it.valid(); it.advance()) {
  // Output as desired.
}