code: public boolean isFractionalTranslation() {
  		if ((Math.abs(matTransform.m03-crystalTranslation.x)>SpaceGroup.DELTA) ||
  			(Math.abs(matTransform.m13-crystalTranslation.y)>SpaceGroup.DELTA) ||
  			(Math.abs(matTransform.m23-crystalTranslation.z)>SpaceGroup.DELTA)) {
  			return true;
  		}
  		return false;
  	}
docs: Tells whether this transformation contains a fractional translational
  component (whatever its rotational component). A fractional translation
  together with a rotation means a screw axis.
  @return