(double-float double-float-epsilon)
(long-float long-float-epsilon))
(- exponent 1.0-exponent))))))
+
+(defun sinc (x)
+ (if (zerop x)
+ 1d0
+ (let ((x (coerce x 'double-float)))
+ (/ (sin x) x))))
+
+
+(defun numbers-within-percentage (a b percent)
+ "Determines if two numbers are equal within a percentage difference."
+ (let ((abs-diff (* 0.01 percent 0.5 (+ (abs a) (abs b)))))
+ (< (abs (- a b)) abs-diff)))