Compare relatively equality between 2 float numbers

isClose.rb

module Math
  RELATIVE_TOLERANCE = 1E-9
  ABSOLUTE_TOLERANCE = 0.0

  ##
  # returns True if a is close in value to b. False otherwise
  #
  # source:
  # https://github.com/PythonCHB/close_pep/blob/master/isclose.py
  # https://www.python.org/dev/peps/pep-0485/#proposed-implementation
  #
  # Params:
  #  a: one of the values to be tested
  #  b: the other value to be tested
  #  rel_tol=1e-9: The relative tolerance -- the amount of error allowed,
  #                 relative to the absolute value of the larger input values.
  #  abs_tol=0.0: The minimum absolute tolerance level
  #              -- useful for comparisons to zero/ numbers near 0/ numbers with very small differences away fom zero.
  # NOTES:
  #  -inf, inf and NaN behave similarly to the IEEE 754 Standard. That
  #  is, NaN is not close to anything, even itself. inf and -inf are
  #  only close to themselves.
  #  The function can be used with any type that supports comparison,
  #  substratcion and multiplication, including Decimal, Fraction, and
  #  Complex
  #  Complex values are compared based on their absolute value.
  def self.close?(a, b, rel_tol: RELATIVE_TOLERANCE, abs_tol: ABSOLUTE_TOLERANCE)
    raise ArgumentError.new('Arguments must be numeric') unless (a.is_a?(Numeric) && b.is_a?(Numeric))
    raise ArgumentError.new('Error tolerance must positive') if (rel_tol < 0.0 || abs_tol < 0.0)

    # short-cut exact equality
    return true if a == b

    # check if any attribute is Infinite
    return false if a.infinite? || b.infinite?

    # weak comparition - the tolerance is scaled by the larger of 2 values
    abs_diff = (a - b).abs
    ((abs_diff <= (rel_tol * b).abs) ||
      (abs_diff <= (rel_tol * a).abs) ||
      (abs_diff < abs_tol))
  end
end