docs: def is_equal(a, b, tol):
      """Ratio test to check if two floating point numbers are equal.
  
      Parameters
      ----------
      a: float
          The first floating point number.
      b: float
          The second floating point number.
      tol: float
          The tolerance used.
  
      Returns
      -------
      bool
          Whether or not the two numbers are deemed equal.
      """
      if a == b or abs(a-b) <= tol * max(abs(a), abs(b)):
          return True
      else:
          return False