code: public boolean areInSameAxis(int tId1, int tId2) {
  		if (tId1==tId2) return true;
  
  		if (axisAngles== null) calcRotAxesAndAngles();
  
  		if (getAxisFoldType(tId1)==1 && getAxisFoldType(tId2)==1) return true;
  
  		// we can't deal yet with improper rotations: we return false whenever either of them is improper
  		if (getAxisFoldType(tId1)<0 || getAxisFoldType(tId2)<0) return false;
  
  		Vector3d axis1 = new Vector3d(axisAngles[tId1].x, axisAngles[tId1].y, axisAngles[tId1].z);
  		Vector3d axis2 = new Vector3d(axisAngles[tId2].x, axisAngles[tId2].y, axisAngles[tId2].z);
  
  		// TODO revise: we might need to consider that the 2 are in same direction but opposite senses
  		// the method is not used at the moment anyway
  		if (deltaComp(axis1.angle(axis2), 0.0, DELTA)) return true;
  
  		return false;
  	}
docs: Returns true if both given transform ids belong to the same crystallographic axis (a, b or c)
  For two non-rotation transformations (i.e. identity operators) it returns true
  @param tId1
  @param tId2
  @return