Subject: [math] Another minor colt mystery


Why do you think they decided that the best hash function for an int
was the int?

 /**
   * Returns a hashcode for the specified value.
   *
   * @return a hash code value for the specified value.
   */
  public static int hash(int value) {
    return value;

    //return value * 0x278DDE6D; // see
org.apache.mahout.math.jet.random.engine.DRand

    /*
    value &= 0x7FFFFFFF; // make it >=0
    int hashCode = 0;
    do hashCode = 31*hashCode + value%10;
    while ((value /= 10) > 0);

    return 28629151*hashCode; // spread even further; h*31^5
    */
  }