Perceptron: Difference between revisions
→{{header|Racket}}
Line 487:
#####OOOOOOOOOOOOOOO
####OOOOOOOOOOOOOOOO</pre>
=={{header|Racket}}==
{{trans|Java}}
<lang racket>#lang racket
(require 2htdp/universe
2htdp/image)
(define (activate s) (if (positive? s) 1 -1))
;; ---------------------------------------------------------------------------------------------------
;; PERCEPTRON
(define perceptron%
(class object%
(super-new)
(init-field n)
(field [weights (build-vector n (λ (i) (- (* (random) 2) 1)))])
(define c 0.001)
(define/public (feed-forward inputs)
(unless (= (vector-length inputs) (vector-length weights))
(error 'feed-forward "weights and inputs lengths mismatch"))
(activate (for/sum ((i (in-vector inputs)) (w (in-vector weights))) (* i w))))
(define/public (train! inputs desired)
(let ((error (- desired (feed-forward inputs))))
(set! weights (vector-map (λ (w i) (+ w (* c error i))) weights inputs))))))
;; ---------------------------------------------------------------------------------------------------
;; TRAINING
(struct training-data (inputs answer))
(define (make-training-data x y f)
(training-data (vector x y 1) (activate (- (f x) y))))
;; ---------------------------------------------------------------------------------------------------
;; DEMO
(define (demo)
(struct demonstration (p w h f i))
(define (draw-classification-space p w h scl n)
(for/fold ((scn (place-image (text (~a (get-field weights p)) 12 "red")
(* scl (/ w 2))
(* scl (/ h 2))
(empty-scene (* w scl) (* h scl)))))
((_ (in-range n)))
(let* ((x (* (random) w))
(y (* (random) h))
(guess+? (positive? (send p feed-forward (vector x y 1)))))
(place-image (rectangle 4 4 (if guess+? 'solid 'outline) (if guess+? 'red 'black))
(- (* scl x) 2) (- (* scl (- h y)) 2)
scn))))
(define the-demo
(let ((w 640/100) (h 360/100) (f (λ (x) (+ (* x 0.7) 0.8))))
(demonstration (new perceptron% [n 3]) w h f 0)))
(define (demo-train p w h f)
(let ((td (make-training-data (* (random) w) (* (random) h) f)))
(send p train! (training-data-inputs td) (training-data-answer td))))
(define tick-handler
(match-lambda
[(and d (demonstration p w h f i))
(for ((_ (in-range 100))) (demo-train p w h f))
(struct-copy demonstration d [i (+ 100 i)])]))
(define draw-demo (match-lambda
[(demonstration p w h f i)
(let ((scl 100))
(scene+line (place-image (text (~a i) 24 "magenta")
(* scl (/ w 2))
(* scl (/ h 3))
(draw-classification-space p w h scl 1000))
0 (* scl (- h (f 0))) (* scl w) (* scl (- h (f w))) "red"))]))
(big-bang the-demo (to-draw draw-demo) (on-tick tick-handler)))
(module+ main (demo))</lang>
Run it and see the image for yourself, I can't get it onto RC!
=={{header|XLISP}}==
| |||