com.expleague.ml.methods.multiclass.spoc.CMLHelper Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jmll

Various ML methods implemented by myself and my students

There is a newer version: 1.4.9

package com.expleague.ml.methods.multiclass.spoc;

import com.expleague.commons.math.vectors.Mx;
import com.expleague.commons.math.vectors.Vec;
import com.expleague.commons.math.vectors.VecTools;
import com.expleague.commons.math.vectors.MxIterator;

/**
 * User: qdeee
 * Date: 14.11.14
 */
public class CMLHelper {
  public static final double MX_IGNORE_THRESHOLD = 0.1;

  public static boolean checkConstraints(final Mx B) {
    for (int l = 0; l < B.columns(); l++) {
      double sumPositive = 0;
      double sumNegative = 0;
      for (int k = 0; k < B.rows(); k++) {
        final double code = B.get(k, l);
        final double absCode = Math.abs(code);
        if (absCode > 1)
          return false;
        sumPositive += absCode + code;
        sumNegative += absCode - code;
      }
      if (sumPositive < 2 || sumNegative < 2)
        return false;
    }
    for (int k = 0; k < B.rows(); k++) {
      final double sum = VecTools.l1(B.row(k));
      if (sum < 1)
        return false;
    }
    return true;
  }

  static void normalizeMx(final Mx codingMatrix, final double mxIgnoreThreshold) {
    for (final MxIterator iter = codingMatrix.nonZeroes(); iter.advance(); ) {
      final double value = iter.value();
      if (Math.abs(value) > mxIgnoreThreshold)
        iter.setValue(Math.signum(value));
      else
        iter.setValue(0.0);
    }
  }

  //check pairwise columns independence
  public static boolean checkColumnsIndependence(final Mx B) {
    for (int j1 = 0; j1 < B.columns(); j1++) {
      final Vec col1 = B.col(j1);
      final double norm1 = VecTools.norm(col1);
      if (norm1 == 0)
        return false;
      for (int j2 = j1 + 1; j2 < B.columns(); j2++) {
        final Vec col2 = B.col(j2);
        final double norm2 = VecTools.norm(col2);
        if (norm2 == 0)
          return false;
        final double cosine = VecTools.multiply(col1, col2) / (norm1 * norm2);
        if (Math.abs(cosine) > 0.999)
          return false;
      }
    }
    return true;
  }
}