;;AUTOLOAD: real-equal
;;AUTODOC: real-equal "test equality of real with rounding errors"
;;(real-equal r1 r2 &optional delta)
;;
;;Returns a non-nil value if r1 and r2 are less than (* delta r1) (a real)
;;apart. 
;;Delta defaults to 1e-15

(defun real-equal (r1 r2 &optional (delta 1e-15))
  (< (abs (- r2 r1)) (abs (* r1 delta)))
)
