Interaction.java

package hex;

import water.DKV;
import water.Iced;
import water.Job;
import water.Key;
import water.fvec.CreateInteractions;
import water.fvec.Frame;
import water.util.Log;
import water.util.PrettyPrint;

import java.util.Arrays;

/**
 * Create new factors that represent interactions of the given factors
 */
public class Interaction extends Iced {
  public Job<Frame> _job;
  public Key<Frame> _source_frame;
  public String[] _factor_columns;
  public boolean _pairwise = false;
  public int _max_factors = 100;
  public int _min_occurrence = 1;
  public boolean _interactOnNA = true;

  transient public int[] _factors = new int[0];

  public Job<Frame> execImpl(Key<Frame> dest ) {
    _job = new Job(dest == null ? Key.make() : dest, Frame.class.getName(), "CreateFrame");
    Frame source_frame = DKV.getGet(_source_frame);
    assert(source_frame != null);
    if (_factor_columns == null || _factor_columns.length == 0) throw new IllegalArgumentException("factor_columns must be specified.");
    if (_pairwise && _factor_columns.length < 3) Log.info("Ignoring the pairwise option, requires 3 or more factors.");
    _factors = new int[_factor_columns.length];
    int count=0;
    for (String v: _factor_columns) {
      int idx = source_frame.find(v);
      if (idx >= 0) {
        if (!source_frame.vecs()[idx].isCategorical()) {
          throw new IllegalArgumentException("Column " + v + " is not categorical.");
        }
        _factors[count++] = idx;
      } else {
        throw new IllegalArgumentException("Column " + v + " not found.");
      }
    }
    CreateInteractions in = new CreateInteractions(this);
    return _job.start(in, in.work());
  }

  @Override public String toString() {
    Frame res = _job.get();
    if (res == null) return "Output frame not found";

    if (!_pairwise)
      return "Created interaction feature " + res.names()[0]
              + " (order: " + _factors.length + ") with " + res.lastVec().domain().length + " factor levels"
        + " in" + PrettyPrint.msecs(_job.msec(), true);
    else
      return "Created " + res.numCols() + " pair-wise interaction features " + Arrays.deepToString(res.names())
        + " (order: 2) in" + PrettyPrint.msecs(_job.msec(), true);
  }
}