From 2ef93b91a1fbd03ed598f47cb0faedf794e0856b Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Thu, 18 Oct 2018 21:53:48 -0700 Subject: [PATCH] pasts --- csp/hacs.rkt | 71 ++++++++++++++++++++++++++++------------------------ 1 file changed, 38 insertions(+), 33 deletions(-) diff --git a/csp/hacs.rkt b/csp/hacs.rkt index 1eb3d4b9..99e8aab3 100644 --- a/csp/hacs.rkt +++ b/csp/hacs.rkt @@ -5,9 +5,14 @@ (struct $csp ([vars #:mutable] [constraints #:mutable]) #:transparent) (struct $constraint (names proc) #:transparent) -(struct $var (name vals) #:transparent) +(struct $var (name vals past conflicts) #:transparent) +(define (+$var name vals [past null] [conflicts null]) + ($var name vals past conflicts)) + (define $var-name? symbol?) (struct $avar $var () #:transparent) +(define (+$avar name vals [past null] [conflicts null]) + ($avar name vals past conflicts)) (struct inconsistency-signal (csp) #:transparent) (define current-select-variable (make-parameter #f)) @@ -40,7 +45,7 @@ ($csp (for/list ([var ($csp-vars csp)]) (if (eq? name ($var-name var)) - ($avar name (list val)) + (+$avar name (list val)) var)) ($csp-constraints csp))) @@ -50,11 +55,11 @@ #:unless ($avar? var)) var)) -(check-equal? (first-unassigned-variable ($csp (list ($var 'a (range 3)) ($var 'b (range 3))) null)) - ($var 'a (range 3))) -(check-equal? (first-unassigned-variable ($csp (list ($avar 'a (range 3)) ($var 'b (range 3))) null)) - ($var 'b (range 3))) -(check-false (first-unassigned-variable ($csp (list ($avar 'a (range 3)) ($avar 'b (range 3))) null))) +(check-equal? (first-unassigned-variable ($csp (list (+$var 'a (range 3)) (+$var 'b (range 3))) null)) + (+$var 'a (range 3))) +(check-equal? (first-unassigned-variable ($csp (list (+$avar 'a (range 3)) (+$var 'b (range 3))) null)) + (+$var 'b (range 3))) +(check-false (first-unassigned-variable ($csp (list (+$avar 'a (range 3)) (+$avar 'b (range 3))) null))) (define first-domain-value values) @@ -72,59 +77,59 @@ ($csp? $var-name? . -> . $csp?) (define aval (first ($csp-vals csp aname))) (define (filter-vals var) - (match-define ($var name vals) var) - (define new-vals - (match (($csp-constraints csp) . relating . (list aname name)) - [(? empty?) vals] - [constraints + (match-define ($var name vals _ _) var) + (match (($csp-constraints csp) . relating . (list aname name)) + [(? empty?) var] + [constraints + (define new-vals (for/list ([val (in-list vals)] #:when (for/and ([constraint (in-list constraints)]) (let ([proc ($constraint-proc constraint)]) (if (eq? name (first ($constraint-names constraint))) (proc val aval) (proc aval val))))) - val)])) - (unless (pair? new-vals) - (raise (inconsistency-signal csp))) - new-vals) + val)) + (unless (pair? new-vals) + (raise (inconsistency-signal csp))) + (+$var name new-vals (cons aname ($var-past var)) ($var-conflicts var))])) ($csp (for/list ([var (in-list ($csp-vars csp))]) (if ($avar? var) var - ($var ($var-name var) (filter-vals var)))) + (filter-vals var))) ($csp-constraints csp))) (check-equal? - ($csp-vars (forward-check ($csp (list ($avar 'a '(1)) ($var 'b (range 2))) null) 'a)) - (list ($avar 'a '(1)) ($var 'b '(0 1)))) + ($csp-vars (forward-check ($csp (list (+$avar 'a '(1)) (+$var 'b (range 2))) null) 'a)) + (list (+$avar 'a '(1)) (+$var 'b '(0 1)))) (check-equal? ;; no inconsistency: b≠c not checked when fc is relative to a - ($csp-vars (forward-check ($csp (list ($avar 'a '(1)) ($var 'b (range 2)) ($var 'c '(0))) + ($csp-vars (forward-check ($csp (list (+$avar 'a '(1)) (+$var 'b (range 2)) (+$var 'c '(0))) (list ($constraint '(a b) (negate =)) ($constraint '(b c) (negate =)))) 'a)) - (list ($avar 'a '(1)) ($var 'b '(0)) ($var 'c '(0)))) + (list (+$avar 'a '(1)) (+$var 'b '(0) '(a)) (+$var 'c '(0)))) (check-equal? ;; no inconsistency: a≠b not checked when fc ignores a, which is already assigned - ($csp-vars (forward-check ($csp (list ($avar 'a '(1)) ($avar 'b '(1)) ($var 'c (range 2))) + ($csp-vars (forward-check ($csp (list (+$avar 'a '(1)) (+$avar 'b '(1)) (+$var 'c (range 2))) (list ($constraint '(a b) (negate =)) ($constraint '(b c) (negate =)))) 'b)) - (list ($avar 'a '(1)) ($avar 'b '(1)) ($var 'c '(0)))) + (list (+$avar 'a '(1)) (+$avar 'b '(1)) (+$var 'c '(0) '(b)))) (check-exn inconsistency-signal? - (λ () ($csp-vars (forward-check ($csp (list ($avar 'a '(1)) - ($var 'b '(1))) + (λ () ($csp-vars (forward-check ($csp (list (+$avar 'a '(1)) + (+$var 'b '(1))) (list ($constraint '(a b) (negate =)))) 'a)))) -(check-equal? ($csp-vars (forward-check ($csp (list ($avar 'a (range 3)) - ($var 'b (range 3))) +(check-equal? ($csp-vars (forward-check ($csp (list (+$avar 'a (range 3)) + (+$var 'b (range 3))) (list ($constraint '(a b) <) ($constraint '(a b) <) ($constraint '(a b) <))) 'a)) - (list ($avar 'a '(0 1 2)) ($var 'b '(1 2)))) + (list (+$avar 'a '(0 1 2)) (+$var 'b '(1 2) '(a)))) (define/contract (backtracking-solver @@ -137,7 +142,7 @@ (let backtrack ([csp csp]) (match (select-unassigned-variable csp) [#false (yield csp)] - [($var name vals) + [($var name vals _ _) (for ([val (in-list (order-domain-values vals))]) (with-handlers ([inconsistency-signal? void]) (let* ([csp (assign-val csp name val)] @@ -165,16 +170,16 @@ (define (neq? a b) (not (eq? a b))) #;(parameterize ([current-inference forward-check]) - (time (solve* ($csp (list ($var 'a (range 3)) - ($var 'b (range 3)) - ($var 'c (range 3))) + (time (solve* ($csp (list (+$var 'a (range 3)) + (+$var 'b (range 3)) + (+$var 'c (range 3))) (list ($constraint '(a b) <>) ($constraint '(a c) <>) ($constraint '(b c) <>)))))) (parameterize ([current-inference forward-check]) (define vds (for/list ([k '(wa nsw t q nt v sa)]) - ($var k '(red green blue)))) + (+$var k '(red green blue)))) (define cs (list ($constraint '(wa nt) neq?) ($constraint '(wa sa) neq?)