RosettaCodeData/Task/Map-range/EchoLisp/map-range.l

31 lines
752 B
Common Lisp

(lib 'plot) ;; interpolation functions
(lib 'compile)
;; rational version
(define (q-map-range x xmin xmax ymin ymax) (+ ymin (/ ( * (- x xmin) (- ymax ymin)) (- xmax xmin))))
;; float version
(define (map-range x xmin xmax ymin ymax) (+ ymin (// ( * (- x xmin) (- ymax ymin)) (- xmax xmin))))
; accelerate it
(compile 'map-range "-vf")
(q-map-range 4 0 10 -1 0)
-3/5
(map-range 4 0 10 -1 0)
-0.6
(linear 4 0 10 -1 0) ;; native
-0.6
(for [(x (in-range 0 10))] (writeln x (q-map-range x 0 10 -1 0) (map-range x 0 10 -1 0)))
0 -1 -1
1 -9/10 -0.9
2 -4/5 -0.8
3 -7/10 -0.7
4 -3/5 -0.6
5 -1/2 -0.5
6 -2/5 -0.4
7 -3/10 -0.3
8 -1/5 -0.2
9 -1/10 -0.1