Making Parallel Mandelbrot Future-Safe

step0.rkt

#lang racket
(require racket/future racket/flonum "pict-helpers.rkt" future-visualizer)

(define W 256)
(define H 256)
(define bts (make-bytes (* 4 W H)))
(module+ main
  (time 
   (begin 
     (mand-range 0 (quotient H 2)) 
     (mand-range (quotient H 2) (- H 1))))
  (display-bytes bts W H))


(define (mand-range start end) 
  (for ([y (in-range start end)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x y))
      (bytes-set! bts 
                  (* 4 (+ (* y H) x)) 
                  val))))

;;in-mandelbrot-set? : int int int int -> int
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) W) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [iters ITERS])
    (cond
      [(> i iters) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                iters)])])))

(define ITERS 255)

step1.rkt

#lang racket
(require racket/future racket/flonum "pict-helpers.rkt" future-visualizer)

(define W 256)
(define H 256)
(define bts (make-bytes (* 4 W H)))
(module+ main
  (time
   (let ([fa (future (λ () (mand-range 0 (quotient H 2))))] 
         [fb (future (λ () (mand-range (quotient H 2) (- H 1))))])
     (touch fa)
     (touch fb)))
  (display-bytes bts W H))

(define (mand-range start end) 
  (for ([y (in-range start end)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x y))
      (bytes-set! bts 
                  (* 4 (+ (* y H) x)) 
                  val))))

;;in-mandelbrot-set? : int int int int -> int
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) W) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [iters ITERS])
    (cond
      [(> i iters) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                iters)])])))

(define ITERS 255)

step2.rkt

#lang racket
(require racket/future racket/flonum "pict-helpers.rkt" future-visualizer)

(define W 256)
(define H 256)
(define bts (make-bytes (* 4 W H)))
(module+ main 
  (visualize-futures
   (let ([fa (future (λ () (mand-range 0 (quotient H 2))))] 
         [fb (future (λ () (mand-range (quotient H 2) (- H 1))))])
     (touch fa)
     (touch fb)))
  (display-bytes bts W H))

(define (mand-range start end) 
  (for ([y (in-range start end)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x y))
      (bytes-set! bts 
                  (* 4 (+ (* y H) x)) 
                  val))))

;;in-mandelbrot-set? : int int int int -> int
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) W) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [iters ITERS])
    (cond
      [(> i iters) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                iters)])])))

(define ITERS 255)

step3.rkt

#lang typed/racket
(require racket/future racket/flonum future-visualizer/typed)
(require/typed "pict-helpers.rkt" [display-bytes (Bytes Integer Integer -> Void)])
(define W 256)
(define H 256)
(define bts (make-bytes (* 4 W H)))
(module+ main 
  (visualize-futures-thunk 
   (λ ()
     (let ([fa (future (λ () (mand-range 0 (quotient H 2))))] 
           [fb (future (λ () (mand-range (quotient H 2) (- H 1))))])
       (touch fa)
       (touch fb))))
  (display-bytes bts W H))

(: mand-range (Integer Integer -> Void))
(define (mand-range start end) 
  (for ([y (- end start)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x (+ y start)))
      (bytes-set! bts 
                  (* 4 (+ (* (+ y start) H) x)) 
                  val))))

(: in-mandelbrot-set? (Integer Integer -> Integer))
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) W) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [ITERS ITERS])
    (cond
      [(> i ITERS) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                ITERS)])])))

(: ITERS Byte)
(define ITERS 255)

step4.rkt

#lang typed/racket
(require racket/future racket/flonum future-visualizer/typed)
(require/typed "pict-helpers.rkt" [display-bytes (Bytes Integer Integer -> Void)])
(define W 256)
(define H 256)
(define bts (make-bytes (* 4 W H)))
(module+ main 
  (time
   (let ([fa (future (λ () (mand-range 0 (quotient H 2))))] 
         [fb (future (λ () (mand-range (quotient H 2) (- H 1))))])
     (touch fa)
     (touch fb)))
  (display-bytes bts W H))


(: mand-range (Integer Integer -> Void))
(define (mand-range start end) 
  (for ([y (- end start)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x (+ y start)))
      (bytes-set! bts 
                  (* 4 (+ (* (+ y start) H) x)) 
                  val))))

(: in-mandelbrot-set? (Integer Integer -> Integer))
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) W) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [ITERS ITERS])
    (cond
      [(> i ITERS) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                ITERS)])])))

(: ITERS Byte)
(define ITERS 255)

step5.rkt

#lang typed/racket
(require racket/future racket/flonum future-visualizer/typed)
(require/typed "pict-helpers.rkt" [display-bytes (Bytes Integer Integer -> Void)])
(define W 1024)
(define H 768)
(define bts (make-bytes (* 4 W H)))
(module+ main 
  (time
   (let ([fa (future (λ () (mand-range 0 (quotient H 2))))] 
         [fb (future (λ () (mand-range (quotient H 2) (- H 1))))])
     (touch fa)
     (touch fb)))
  (display-bytes bts W H))


(: mand-range (Integer Integer -> Void))
(define (mand-range start end) 
  (for ([y (- end start)]) 
    (for ([x (in-range W)])
      (define val (in-mandelbrot-set? x (+ y start)))
      (bytes-set! bts 
                  (* 4 (+ (* (+ y start) W) x)) 
                  val))))

(: in-mandelbrot-set? (Integer Integer -> Integer))
(define (in-mandelbrot-set? x y)
  (define c (make-rectangular
             (- (/ (* 2.0 (->fl x)) W) 1.5) 
             (- (/ (* 2.0 (->fl y)) H) 1.0)))
  (let loop ([i 0] [z 0.0+0.0i] [ITERS ITERS])
    (cond
      [(> i ITERS) 255]
      [else
       (define zq (* z z))
       (cond
         [(> (magnitude zq) 2.0) i]
         [else
          (loop (add1 i)
                (+ zq c)
                ITERS)])])))

(: ITERS Byte)
(define ITERS 255)