racket/collects/plot/common/sample.rkt

307 lines
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Racket

#lang racket/base
;; Functions that sample from functions, and functions that create memoized samplers.
(require racket/match racket/flonum racket/math racket/contract racket/list racket/vector
unstable/latent-contract/defthing
"math.rkt"
"axis-transform.rkt")
(provide (all-defined-out))
(defproc (build-linear-seq [start real?] [step real?]
[num exact-nonnegative-integer?]
[min-val real? start]
[max-val real? (+ start (* (- num 1) step))]
) (listof real?)
(define n-start (max 0 (inexact->exact (floor (/ (- min-val start) step)))))
(define n-end (min num (+ (inexact->exact (ceiling (/ (- max-val start) step))) 1)))
(for*/list ([n (in-range n-start n-end)]
[x (in-value (+ start (* n step)))]
#:when (<= min-val x max-val))
x))
(defproc (linear-seq [start real?] [end real?] [num exact-nonnegative-integer?]
[#:start? start? boolean? #t]
[#:end? end? boolean? #t]) (listof real?)
(cond
[(zero? num) empty]
; ambiguous request: arbitrarily return start
[(and start? end? (= 1 num)) (list start)]
[(end . < . start) (reverse (linear-seq end start num #:start? end? #:end? start?))]
[(end . = . start) (build-list num (λ _ start))]
[else
(define size (- end start))
(define step (/ size (cond [(and start? end?) (- num 1)]
[(or start? end?) (- num 1/2)]
[else num])))
(define real-start
(cond [start? start]
[else (+ start (* 1/2 step))]))
(build-linear-seq real-start step num)]))
(defproc (linear-seq* [points (listof real?)] [num exact-nonnegative-integer?]
[#:start? start? boolean? #t]
[#:end? end? boolean? #t]) (listof real?)
(let/ec return
(when (empty? points) (raise-type-error 'linear-seq* "nonempty (listof real?)" points))
(define pts (list->vector points))
(define len (vector-length pts))
(define indexes (linear-seq 0 (sub1 len) num #:start? start? #:end? end?))
(define int-parts (map floor indexes))
(define frac-parts (map - indexes int-parts))
(map (λ (i f)
(if (= i (sub1 len))
(vector-ref pts i)
(blend (vector-ref pts (add1 i)) (vector-ref pts i) f)))
int-parts frac-parts)))
(defproc (nonlinear-seq [start real?] [end real?] [num exact-nonnegative-integer?]
[transform axis-transform/c]
[#:start? start? boolean? #t]
[#:end? end? boolean? #t]) (listof real?)
(match-define (invertible-function _ finv) (apply-axis-transform transform start end))
(map finv (linear-seq start end num #:start? start? #:end? end?)))
;; ===================================================================================================
(define (ensure-endpoints xs i-min i-max)
(cond [(empty? xs) (cond [(i-min . = . i-max) (list i-min)]
[else (list i-min i-max)])]
[else
(define xs-min (first xs))
(define xs-max (last xs))
(let* ([xs (if (xs-min . <= . i-min) xs (cons i-min xs))]
[xs (if (xs-max . >= . i-max) xs (append xs (list i-max)))])
xs)]))
(defproc (sample-points [outer-ivl rational-ivl?] [inner-ivl ivl?]
[num exact-nonnegative-integer?]
[transform axis-transform/c id-transform]) (listof real?)
(let* ([inner-ivl (ivl-meet inner-ivl outer-ivl)]
[inner-ivl (ivl-inexact->exact inner-ivl)]
[outer-ivl (ivl-inexact->exact outer-ivl)])
(match-define (ivl o-min o-max) outer-ivl)
(match-define (ivl i-min i-max) inner-ivl)
(match-define (invertible-function f finv) (apply-axis-transform transform o-min o-max))
(cond
[(ivl-empty? inner-ivl) empty]
[(= num 0) empty]
[(or (= o-min o-max) (= num 1))
(cond [(<= i-min o-min i-max) (build-list num (λ _ o-min))]
[else empty])]
[else
(define step (/ (- o-max o-min) (- num 1)))
(let* ([xs (map finv (build-linear-seq o-min step num (f i-min) (f i-max)))]
[xs (remove-duplicates (map (λ (x) (clamp-real x inner-ivl)) xs))])
(ensure-endpoints xs i-min i-max))])))
;; ===================================================================================================
(struct mapped-function (f fmap) #:transparent
#:property prop:procedure
(λ (g x) ((mapped-function-f g) x)))
(define (map* f xs)
(match f
#;; gives obviously wrong chaperone error (tries to apply a hash?):
[(mapped-function _ fmap) (fmap xs)]
[(? mapped-function?) ((mapped-function-fmap f) xs)]
[_ (map f xs)]))
;; ===================================================================================================
;; Making memoized samplers
(struct sample (xs ys y-min y-max) #:transparent)
(struct 2d-sample (xs ys zss z-min z-max) #:transparent)
(struct 3d-sample (xs ys zs dsss d-min d-max) #:transparent)
(defcontract sampler/c
(-> rational-ivl? exact-nonnegative-integer? sample?))
(defcontract 2d-sampler/c
(-> (vector/c rational-ivl? rational-ivl?)
(vector/c exact-nonnegative-integer? exact-nonnegative-integer?)
2d-sample?))
(defcontract 3d-sampler/c
(-> (vector/c rational-ivl? rational-ivl? rational-ivl?)
(vector/c exact-nonnegative-integer? exact-nonnegative-integer? exact-nonnegative-integer?)
3d-sample?))
(defproc (make-function->sampler [transform-thnk (-> axis-transform/c)]
) (-> (real? . -> . real?) ivl? sampler/c)
(λ (g inner-ivl)
(define f (λ (x) (with-handlers ([exn:fail? (λ (_) +nan.0)]) (g x))))
(define memo (make-hash))
(λ (outer-ivl num)
(define tx (transform-thnk))
(hash-ref! memo (vector outer-ivl num tx)
(λ ()
(define xs (sample-points outer-ivl inner-ivl num tx))
(define ys (map* f xs))
(define rys (filter rational? ys))
(define-values (y-min y-max)
(cond [(empty? rys) (values #f #f)]
[else (values (apply min* rys) (apply max* rys))]))
(sample xs ys
(maybe-inexact->exact y-min)
(maybe-inexact->exact y-max)))))))
(defproc (make-2d-function->sampler [transform-x-thnk (-> axis-transform/c)]
[transform-y-thnk (-> axis-transform/c)]
) (-> (real? real? . -> . real?)
(vector/c ivl? ivl?)
2d-sampler/c)
(λ (g inner-rect)
(define f (λ (x y) (with-handlers ([exn:fail? (λ (_) +nan.0)]) (g x y))))
(define memo (make-hash))
(λ (outer-rect nums)
(define tx (transform-x-thnk))
(define ty (transform-y-thnk))
(hash-ref! memo (vector outer-rect nums tx ty)
(λ ()
(match-define (vector outer-x-ivl outer-y-ivl) outer-rect)
(match-define (vector inner-x-ivl inner-y-ivl) inner-rect)
(match-define (vector x-num y-num) nums)
(define xs (sample-points outer-x-ivl inner-x-ivl x-num tx))
(define ys (sample-points outer-y-ivl inner-y-ivl y-num ty))
(define z-min #f)
(define z-max #f)
(define zss (for/vector #:length (length ys) ([y (in-list ys)])
(for/vector #:length (length xs) ([x (in-list xs)])
(let ([z (f x y)])
(when (rational? z)
(unless (and z-min (z . >= . z-min)) (set! z-min z))
(unless (and z-max (z . <= . z-max)) (set! z-max z)))
z))))
(2d-sample xs ys zss
(maybe-inexact->exact z-min)
(maybe-inexact->exact z-max)))))))
(defproc (make-3d-function->sampler [transform-x-thnk (-> axis-transform/c)]
[transform-y-thnk (-> axis-transform/c)]
[transform-z-thnk (-> axis-transform/c)]
) (-> (real? real? real? . -> . real?)
(vector/c ivl? ivl? ivl?)
3d-sampler/c)
(λ (g inner-rect)
(define f (λ (x y z) (with-handlers ([exn:fail? (λ (_) +nan.0)]) (g x y z))))
(define memo (make-hash))
(λ (outer-rect nums)
(define tx (transform-x-thnk))
(define ty (transform-y-thnk))
(define tz (transform-z-thnk))
(hash-ref! memo (vector outer-rect nums tx ty tz)
(λ ()
(match-define (vector outer-x-ivl outer-y-ivl outer-z-ivl) outer-rect)
(match-define (vector inner-x-ivl inner-y-ivl inner-z-ivl) inner-rect)
(match-define (vector x-num y-num z-num) nums)
(define xs (sample-points outer-x-ivl inner-x-ivl x-num tx))
(define ys (sample-points outer-y-ivl inner-y-ivl y-num ty))
(define zs (sample-points outer-z-ivl inner-z-ivl z-num tz))
(define d-min #f)
(define d-max #f)
(define dsss (for/vector #:length (length zs) ([z (in-list zs)])
(for/vector #:length (length ys) ([y (in-list ys)])
(for/vector #:length (length xs) ([x (in-list xs)])
(let ([d (f x y z)])
(when (rational? d)
(unless (and d-min (d . >= . d-min)) (set! d-min d))
(unless (and d-max (d . <= . d-max)) (set! d-max d)))
d)))))
(3d-sample xs ys zs dsss
(maybe-inexact->exact d-min)
(maybe-inexact->exact d-max)))))))
(define-syntax-rule (for-2d-sample (xa xb ya yb z1 z2 z3 z4) sample expr ...)
(let ()
(match-define (2d-sample xs ys zss fz-min fz-max) sample)
(define ya (first ys))
(define zs0 (vector-ref zss 0))
(for/fold ([ya ya] [zs0 zs0]) ([yb (in-list (rest ys))]
[zs1 (in-vector zss 1)])
(define xa (first xs))
(define z1 (vector-ref zs0 0))
(define z4 (vector-ref zs1 0))
(for/fold ([xa xa] [z1 z1] [z4 z4]) ([xb (in-list (rest xs))]
[z2 (in-vector zs0 1)]
[z3 (in-vector zs1 1)])
expr ...
(values xb z2 z3))
(values yb zs1))))
(define-syntax-rule (for-3d-sample (xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8) sample expr ...)
(let ()
(match-define (3d-sample xs ys zs dsss fd-min fd-max) sample)
(define za (first zs))
(define dss0 (vector-ref dsss 0))
(for/fold ([za za] [dss0 dss0]) ([zb (in-list (rest zs))]
[dss1 (in-vector dsss 1)])
(define ya (first ys))
(define ds00 (vector-ref dss0 0))
(define ds10 (vector-ref dss1 0))
(for/fold ([ya ya] [ds00 ds00] [ds10 ds10]) ([yb (in-list (rest ys))]
[ds01 (in-vector dss0 1)]
[ds11 (in-vector dss1 1)])
(define xa (first xs))
(define d1 (vector-ref ds00 0))
(define d4 (vector-ref ds01 0))
(define d5 (vector-ref ds10 0))
(define d8 (vector-ref ds11 0))
(for/fold ([xa xa] [d1 d1] [d4 d4] [d5 d5] [d8 d8]) ([xb (in-list (rest xs))]
[d2 (in-vector ds00 1)]
[d3 (in-vector ds01 1)]
[d6 (in-vector ds10 1)]
[d7 (in-vector ds11 1)])
expr ...
(values xb d2 d3 d6 d7))
(values yb ds01 ds11))
(values zb dss1))))
(defproc (sample-exact->inexact [s sample?]) sample?
(match-define (sample xs ys y-min y-max) s)
(sample (map exact->inexact xs) (map exact->inexact ys)
y-min y-max))
(defproc (2d-sample-exact->inexact [s 2d-sample?]) 2d-sample?
(match-define (2d-sample xs ys zss z-min z-max) s)
(2d-sample (map exact->inexact xs) (map exact->inexact ys)
(for/vector #:length (vector-length zss) ([zs (in-vector zss)])
(for/vector #:length (vector-length zs) ([z (in-vector zs)])
(exact->inexact z)))
z-min z-max))
(defproc (3d-sample-exact->inexact [s 3d-sample?]) 3d-sample?
(match-define (3d-sample xs ys zs dsss d-min d-max) s)
(3d-sample (map exact->inexact xs) (map exact->inexact ys) (map exact->inexact zs)
(for/vector #:length (vector-length dsss) ([dss (in-vector dsss)])
(for/vector #:length (vector-length dss) ([ds (in-vector dss)])
(for/vector #:length (vector-length ds) ([d (in-vector ds)])
(exact->inexact d))))
d-min d-max))
(defproc (flonum-ok-for-2d? [x-min rational?] [x-max rational?]
[y-min rational?] [y-max rational?]) boolean?
(and (flonum-ok-for-range? x-min x-max 10000)
(flonum-ok-for-range? y-min y-max 10000)))
(defproc (flonum-ok-for-3d? [x-min rational?] [x-max rational?]
[y-min rational?] [y-max rational?]
[z-min rational?] [z-max rational?]) boolean?
(and (flonum-ok-for-range? x-min x-max 10000)
(flonum-ok-for-range? y-min y-max 10000)
(flonum-ok-for-range? z-min z-max 10000)))
(defproc (flonum-ok-for-4d? [x-min rational?] [x-max rational?]
[y-min rational?] [y-max rational?]
[z-min rational?] [z-max rational?]
[d-min rational?] [d-max rational?]) boolean?
(and (flonum-ok-for-range? x-min x-max 10000)
(flonum-ok-for-range? y-min y-max 10000)
(flonum-ok-for-range? z-min z-max 10000)
(flonum-ok-for-range? d-min d-max 10000)))