ph-math/src/main/java/com/helger/numbercruncher/mathutils/FixedPointRootFinder.java
@Override
  protected void computeNextPosition ()
  {
    m_fPrevXn = m_fXn;
    m_fXn = m_fGn;
    m_fGn = m_aFunction.at (m_fXn);
  }
@Override
  protected void computeNextPosition ()
  {
    m_fPrevXn = m_fXn;
    m_fXn = m_fGn;
    m_fGn = m_aFunction.at (m_fXn);
  }
Compute the next position of xn.