package de.lmu.ifi.dbs.elki.evaluation.scores.adapter;
/*
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2015
 Ludwig-Maximilians-Universität München
 Lehr- und Forschungseinheit für Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import de.lmu.ifi.dbs.elki.data.NumberVector;
import de.lmu.ifi.dbs.elki.evaluation.scores.ScoreEvaluation.Predicate;

/**
 * Class that uses a NumberVector as reference, and considers all zero values as
 * positive entries.
 * 
 * @apiviz.composedOf NumberVector
 * 
 * @author Erich Schubert
 * @since 0.7.0
 */
public class VectorZero implements Predicate<IncreasingVectorIter> {
  /**
   * Vector to use as reference
   */
  NumberVector vec;

  /**
   * Number of positive values.
   */
  int numpos;

  /**
   * Constructor.
   * 
   * @param vec Reference vector.
   */
  public VectorZero(NumberVector vec) {
    this.vec = vec;
    this.numpos = 0;
    for(int i = 0, l = vec.getDimensionality(); i < l; i++) {
      if(Math.abs(vec.doubleValue(i)) < Double.MIN_NORMAL) {
        ++numpos;
      }
    }
  }

  @Override
  public boolean test(IncreasingVectorIter o) {
    return Math.abs(vec.doubleValue(o.dim())) < Double.MIN_NORMAL;
  }

  @Override
  public int numPositive() {
    return numpos;
  }
}