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Matthew Butterick 6 years ago
parent 400b484943
commit 558c905393
2 changed files with 90 additions and 95 deletions
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1
csp/csp/hacs-map.rkt
Unescape Escape View File

@ -2,7 +2,6 @@
(require "hacs.rkt" sugar/debug) (require "hacs.rkt" sugar/debug)
(module+ test (require rackunit)) (module+ test (require rackunit))
(define (map-coloring-csp colors neighbors) (define (map-coloring-csp colors neighbors)
(define names (remove-duplicates (flatten neighbors) eq?)) (define names (remove-duplicates (flatten neighbors) eq?))
(define vds (for/list ([name (in-list names)]) (define vds (for/list ([name (in-list names)])

184
csp/csp/hacs.rkt
Unescape Escape View File

@ -15,8 +15,8 @@
(let loop ([argss argss][acc empty]) (let loop ([argss argss][acc empty])
(if (null? argss) (if (null? argss)
(yield (reverse acc)) (yield (reverse acc))
(for ([arg (in-list (car argss))]) (for ([arg (car argss)])
(loop (cdr argss) (cons arg acc)))))))) (loop (cdr argss) (cons arg acc))))))))
(struct csp (vars constraints [assignments #:auto] [checks #:auto]) (struct csp (vars constraints [assignments #:auto] [checks #:auto])
#:mutable #:transparent #:auto-value 0) #:mutable #:transparent #:auto-value 0)
@ -33,7 +33,7 @@
(raise-argument-error 'constraint-proc "csp" prob)) (raise-argument-error 'constraint-proc "csp" prob))
;; apply proc in many-to-many style ;; apply proc in many-to-many style
(for/and ([args (in-cartesian (map (λ (name) (find-domain prob name)) (constraint-names const)))]) (for/and ([args (in-cartesian (map (λ (name) (find-domain prob name)) (constraint-names const)))])
(apply (constraint-proc const) args)))) (apply (constraint-proc const) args))))
(define name? symbol?) (define name? symbol?)
@ -74,15 +74,15 @@
((csp? (or/c (listof name?) procedure?)) ((or/c (listof any/c) procedure?)) . ->* . void?) ((csp? (or/c (listof name?) procedure?)) ((or/c (listof any/c) procedure?)) . ->* . void?)
(for/fold ([vrs (vars prob)] (for/fold ([vrs (vars prob)]
#:result (set-csp-vars! prob vrs)) #:result (set-csp-vars! prob vrs))
([name (in-list (if (procedure? names-or-procedure) ([name (in-list (match names-or-procedure
(names-or-procedure) [(? procedure? proc) (proc)]
names-or-procedure))]) [names names]))])
(when (memq name (map var-name vrs)) (when (memq name (map var-name vrs))
(raise-argument-error 'add-vars! "var that doesn't already exist" name)) (raise-argument-error 'add-vars! "var that doesn't already exist" name))
(append vrs (list (var name (append vrs (list (var name
(if (procedure? vals-or-procedure) (if (procedure? vals-or-procedure)
(vals-or-procedure) (vals-or-procedure)
vals-or-procedure)))))) vals-or-procedure))))))
(define/contract (add-var! prob name [vals-or-procedure empty]) (define/contract (add-var! prob name [vals-or-procedure empty])
((csp? name?) ((or/c (listof any/c) procedure?)) . ->* . void?) ((csp? name?) ((or/c (listof any/c) procedure?)) . ->* . void?)
@ -92,11 +92,11 @@
((csp? procedure? (listof (listof name?))) ((or/c #false name?)) . ->* . void?) ((csp? procedure? (listof (listof name?))) ((or/c #false name?)) . ->* . void?)
(set-csp-constraints! prob (append (constraints prob) (set-csp-constraints! prob (append (constraints prob)
(for/list ([names (in-list namess)]) (for/list ([names (in-list namess)])
(for ([name (in-list names)]) (for ([name (in-list names)])
(check-name-in-csp! 'add-constraints! prob name)) (check-name-in-csp! 'add-constraints! prob name))
(make-constraint names (if proc-name (make-constraint names (if proc-name
(procedure-rename proc proc-name) (procedure-rename proc proc-name)
proc)))))) proc))))))
(define/contract (add-pairwise-constraint! prob proc var-names [proc-name #false]) (define/contract (add-pairwise-constraint! prob proc var-names [proc-name #false])
((csp? procedure? (listof name?)) (name?) . ->* . void?) ((csp? procedure? (listof name?)) (name?) . ->* . void?)
@ -132,7 +132,7 @@
(check-name-in-csp! 'find-var prob name) (check-name-in-csp! 'find-var prob name)
(for/first ([vr (in-vars prob)] (for/first ([vr (in-vars prob)]
#:when (eq? name (var-name vr))) #:when (eq? name (var-name vr)))
vr)) vr))
(define/contract (find-domain prob name) (define/contract (find-domain prob name)
(csp? name? . -> . (listof any/c)) (csp? name? . -> . (listof any/c))
@ -145,7 +145,7 @@
(csp? name? . -> . any/c) (csp? name? . -> . any/c)
(for/or ([vr (in-vars prob)] (for/or ([vr (in-vars prob)]
#:when (assigned-var? vr)) #:when (assigned-var? vr))
(eq? name (var-name vr)))) (eq? name (var-name vr))))
(define/contract (reduce-function-arity proc pattern) (define/contract (reduce-function-arity proc pattern)
(procedure? (listof any/c) . -> . procedure?) (procedure? (listof any/c) . -> . procedure?)
@ -177,20 +177,20 @@
(ormap assigned? (constraint-names constraint))) (ormap assigned? (constraint-names constraint)))
(make-csp (vars prob) (make-csp (vars prob)
(for/list ([const (in-constraints prob)]) (for/list ([const (in-constraints prob)])
(cond (cond
;; no point reducing 2-arity functions because they will be consumed by forward checking ;; no point reducing 2-arity functions because they will be consumed by forward checking
[(and (or (not minimum-arity) (<= minimum-arity (constraint-arity const))) [(and (or (not minimum-arity) (<= minimum-arity (constraint-arity const)))
(partially-assigned? const)) (partially-assigned? const))
(match-define (constraint cnames proc) const) (match-define (constraint cnames proc) const)
;; pattern is mix of values and boxed symbols (indicating variables to persist) ;; pattern is mix of values and boxed symbols (indicating variables to persist)
;; use boxes here as cheap way to distinguish id symbols from value symbols ;; use boxes here as cheap way to distinguish id symbols from value symbols
(define reduce-arity-pattern (for/list ([cname (in-list cnames)]) (define reduce-arity-pattern (for/list ([cname (in-list cnames)])
(if (assigned? cname) (if (assigned? cname)
(first (find-domain prob cname)) (first (find-domain prob cname))
(box cname)))) (box cname))))
(constraint (filter-not assigned? cnames) (constraint (filter-not assigned? cnames)
(reduce-function-arity proc reduce-arity-pattern))] (reduce-function-arity proc reduce-arity-pattern))]
[else const])))) [else const]))))
(define nassns 0) (define nassns 0)
@ -200,14 +200,18 @@
(define (reset-nfcs!) (set! nfchecks 0)) (define (reset-nfcs!) (set! nfchecks 0))
(define nchecks 0)
(define (reset-nchecks!) (set! nchecks 0))
(define/contract (assign-val prob name val) (define/contract (assign-val prob name val)
(csp? name? any/c . -> . csp?) (csp? name? any/c . -> . csp?)
(when-debug (set! nassns (add1 nassns))) (when-debug (set! nassns (add1 nassns)))
(make-csp (make-csp
(for/list ([vr (vars prob)]) (for/list ([vr (in-vars prob)])
(if (eq? name (var-name vr)) (if (eq? name (var-name vr))
(assigned-var name (list val)) (assigned-var name (list val))
vr)) vr))
(constraints prob))) (constraints prob)))
(define/contract (unassigned-vars prob) (define/contract (unassigned-vars prob)
@ -232,7 +236,7 @@
(csp? var? . -> . natural?) (csp? var? . -> . natural?)
(for/sum ([const (in-constraints prob)] (for/sum ([const (in-constraints prob)]
#:when (memq (var-name var) (constraint-names const))) #:when (memq (var-name var) (constraint-names const)))
1)) 1))
(define/contract (domain-length var) (define/contract (domain-length var)
(var? . -> . natural?) (var? . -> . natural?)
@ -255,7 +259,7 @@
(random-pick (for/list ([uv (in-list mrv-uvars)] (random-pick (for/list ([uv (in-list mrv-uvars)]
[degree (in-list degrees)] [degree (in-list degrees)]
#:when (= max-degree degree)) #:when (= max-degree degree))
uv))])])) uv))])]))
(define first-domain-value values) (define first-domain-value values)
@ -267,8 +271,8 @@
[cnames (in-value (constraint-names const))] [cnames (in-value (constraint-names const))]
#:when (and (= (length names) (length cnames)) #:when (and (= (length names) (length cnames))
(for/and ([name (in-list names)]) (for/and ([name (in-list names)])
(memq name cnames)))) (memq name cnames))))
const)) const))
(define (two-arity? const) (= 2 (constraint-arity const))) (define (two-arity? const) (= 2 (constraint-arity const)))
@ -278,33 +282,33 @@
(define/contract (forward-check prob ref-name) (define/contract (forward-check prob ref-name)
(csp? name? . -> . csp?) (csp? name? . -> . csp?)
(define aval (first (find-domain prob ref-name))) (define aval (first (find-domain prob ref-name)))
(define (check-var v) (define (check-var vr)
(match v (match vr
;; don't check against assigned vars, or the reference var ;; don't check against assigned vars, or the reference var
;; (which is probably assigned but maybe not) ;; (which is probably assigned but maybe not)
[(? (λ (x) (or (assigned-var? x) (eq? (var-name x) ref-name)))) v] [(? (λ (x) (or (assigned-var? x) (eq? (var-name x) ref-name)))) vr]
[(var name vals) [(var name vals)
(match ((constraints prob) . relating-only . (list ref-name name)) (match ((constraints prob) . relating-only . (list ref-name name))
[(? empty?) v] [(? empty?) vr]
[constraints [constraints
(define new-vals (define new-vals
(for/list ([val (in-list vals)] (for/list ([val (in-list vals)]
#:when (for/and ([const (in-list constraints)]) #:when (for/and ([const (in-list constraints)])
(let ([proc (constraint-proc const)]) (let ([proc (constraint-proc const)])
(if (eq? name (first (constraint-names const))) (if (eq? name (first (constraint-names const)))
(proc val aval) (proc val aval)
(proc aval val))))) (proc aval val)))))
val)) val))
(checked-variable name new-vals (cons ref-name (match v (checked-variable name new-vals (cons ref-name (match vr
[(checked-variable _ _ history) history] [(checked-variable _ _ history) history]
[else null])))])])) [else null])))])]))
(define checked-vars (map check-var (vars prob))) (define checked-vars (map check-var (vars prob)))
(when-debug (set! nfchecks (+ (length checked-vars) nchecks))) (when-debug (set! nfchecks (+ (length checked-vars) nchecks)))
;; conflict-set will be empty if there are no empty domains (as we would hope) ;; conflict-set will be empty if there are no empty domains (as we would hope)
(define conflict-set (for*/list ([cv (in-list checked-vars)] (define conflict-set (for*/list ([cvr (in-list checked-vars)]
#:when (empty? (domain cv)) #:when (empty? (domain cvr))
[name (in-list (history cv))]) [name (in-list (history cvr))])
name)) name))
;; for conflict-directed backjumping it's essential to forward-check ALL vars ;; for conflict-directed backjumping it's essential to forward-check ALL vars
;; (even after an empty domain is generated) and combine their conflicts ;; (even after an empty domain is generated) and combine their conflicts
;; so we can discover the *most recent past var* that could be the culprit. ;; so we can discover the *most recent past var* that could be the culprit.
@ -320,7 +324,7 @@
(constraint-relates? const ref-name) (constraint-relates? const ref-name)
(let ([other-name (first (remq ref-name (constraint-names const)))]) (let ([other-name (first (remq ref-name (constraint-names const)))])
(singleton-var? (find-var prob other-name))))) (singleton-var? (find-var prob other-name)))))
const)) const))
(make-csp checked-vars nonsingleton-constraints)) (make-csp checked-vars nonsingleton-constraints))
(define/contract (constraint-checkable? const names) (define/contract (constraint-checkable? const names)
@ -328,7 +332,7 @@
;; constraint is checkable if all constraint names ;; constraint is checkable if all constraint names
;; are in target list of names. ;; are in target list of names.
(for/and ([cname (in-list (constraint-names const))]) (for/and ([cname (in-list (constraint-names const))])
(memq cname names))) (memq cname names)))
(define/contract (constraint-arity const) (define/contract (constraint-arity const)
(constraint? . -> . natural?) (constraint? . -> . natural?)
@ -337,8 +341,6 @@
(define (singleton-var? var) (define (singleton-var? var)
(= 1 (domain-length var))) (= 1 (domain-length var)))
(define nchecks 0)
(define (reset-nchecks!) (set! nchecks 0))
(define/contract (check-constraints prob [mandatory-names #f] #:conflicts [conflict-count? #f]) (define/contract (check-constraints prob [mandatory-names #f] #:conflicts [conflict-count? #f])
((csp?) ((listof name?) #:conflicts boolean?) . ->* . (or/c csp? natural?)) ((csp?) ((listof name?) #:conflicts boolean?) . ->* . (or/c csp? natural?))
;; this time, we're not limited to assigned variables ;; this time, we're not limited to assigned variables
@ -346,26 +348,26 @@
;; we also want to use "singleton" vars (that is, vars that have been reduced to a single domain value by forward checking) ;; we also want to use "singleton" vars (that is, vars that have been reduced to a single domain value by forward checking)
(define singleton-varnames (for/list ([vr (in-vars prob)] (define singleton-varnames (for/list ([vr (in-vars prob)]
#:when (singleton-var? vr)) #:when (singleton-var? vr))
(var-name vr))) (var-name vr)))
(define-values (checkable-consts other-consts) (define-values (checkable-consts other-consts)
(partition (λ (const) (and (constraint-checkable? const singleton-varnames) (partition (λ (const) (and (constraint-checkable? const singleton-varnames)
(or (not mandatory-names) (or (not mandatory-names)
(for/and ([name (in-list mandatory-names)]) (for/and ([name (in-list mandatory-names)])
(constraint-relates? const name))))) (constraint-relates? const name)))))
(constraints prob))) (constraints prob)))
(cond (cond
[conflict-count? [conflict-count?
(define conflict-count (define conflict-count
(for/sum ([constraint (in-list checkable-consts)] (for/sum ([constraint (in-list checkable-consts)]
#:unless (constraint prob)) #:unless (constraint prob))
1)) 1))
(when-debug (set! nchecks (+ conflict-count nchecks))) (when-debug (set! nchecks (+ conflict-count nchecks)))
conflict-count] conflict-count]
[else [else
(for ([(constraint idx) (in-indexed checkable-consts)] (for ([(constraint idx) (in-indexed checkable-consts)]
#:unless (constraint prob)) #:unless (constraint prob))
(when-debug (set! nchecks (+ (add1 idx) nchecks))) (when-debug (set! nchecks (+ (add1 idx) nchecks)))
(backtrack!)) (backtrack!))
;; discard checked constraints, since they have no further reason to live ;; discard checked constraints, since they have no further reason to live
(make-csp (vars prob) other-consts)])) (make-csp (vars prob) other-consts)]))
@ -374,15 +376,15 @@
;; todo: why does this function slow down searches? ;; todo: why does this function slow down searches?
(make-csp (make-csp
(for/list ([vr (in-vars prob)]) (for/list ([vr (in-vars prob)])
(match-define (var name vals) vr) (match-define (var name vals) vr)
(define procs (for*/list ([const (in-constraints prob)] (define procs (for*/list ([const (in-constraints prob)]
[cnames (in-value (constraint-names const))] [cnames (in-value (constraint-names const))]
#:when (and (= 1 (length cnames)) (eq? name (car cnames)))) #:when (and (= 1 (length cnames)) (eq? name (car cnames))))
(constraint-proc const))) (constraint-proc const)))
(var name (var name
(for*/fold ([vals vals]) (for*/fold ([vals vals])
([proc (in-list procs)]) ([proc (in-list procs)])
(filter proc vals)))) (filter proc vals))))
(constraints prob))) (constraints prob)))
(define/contract (backtracking-solver (define/contract (backtracking-solver
@ -441,9 +443,9 @@
((csp?) (integer?) . ->* . generator?) ((csp?) (integer?) . ->* . generator?)
(generator () (generator ()
(for ([thread-count (or (current-thread-count) 1)]) ; todo: what is ideal thread count? (for ([thread-count (or (current-thread-count) 1)]) ; todo: what is ideal thread count?
(make-min-conflcts-thread prob thread-count max-steps)) (make-min-conflcts-thread prob thread-count max-steps))
(for ([i (in-naturals)]) (for ([i (in-naturals)])
(yield (thread-receive))))) (yield (thread-receive)))))
(define/contract (optimal-stop-min proc xs) (define/contract (optimal-stop-min proc xs)
(procedure? (listof any/c) . -> . any/c) (procedure? (listof any/c) . -> . any/c)
@ -451,7 +453,7 @@
(define threshold (argmin proc sample)) (define threshold (argmin proc sample))
(or (for/first ([candidate (in-list candidates)] (or (for/first ([candidate (in-list candidates)]
#:when (<= (proc candidate) threshold)) #:when (<= (proc candidate) threshold))
candidate) candidate)
(last candidates))) (last candidates)))
(define/contract (conflicted-variable-names prob) (define/contract (conflicted-variable-names prob)
@ -459,7 +461,7 @@
;; Return a list of variables in current assignment that are conflicted ;; Return a list of variables in current assignment that are conflicted
(for/list ([name (in-variable-names prob)] (for/list ([name (in-variable-names prob)]
#:when (positive? (nconflicts prob name))) #:when (positive? (nconflicts prob name)))
name)) name))
(define/contract (min-conflicts-value prob name vals) (define/contract (min-conflicts-value prob name vals)
(csp? name? (listof any/c) . -> . any/c) (csp? name? (listof any/c) . -> . any/c)
@ -468,7 +470,7 @@
#:cache-keys? #true)) #:cache-keys? #true))
(for/first ([val (in-list vals-by-conflict)] (for/first ([val (in-list vals-by-conflict)]
#:unless (equal? val (first (find-domain prob name)))) ;; but change the value #:unless (equal? val (first (find-domain prob name)))) ;; but change the value
val)) val))
(define no-value-sig (gensym)) (define no-value-sig (gensym))
@ -482,8 +484,8 @@
(define/contract (csp->assocs prob) (define/contract (csp->assocs prob)
(csp? . -> . (listof (cons/c name? any/c))) (csp? . -> . (listof (cons/c name? any/c)))
(for/list ([vr (in-vars prob)]) (for/list ([vr (in-vars prob)])
(match vr (match vr
[(var name (list val)) (cons name val)]))) [(var name (list val)) (cons name val)])))
(define/contract (combine-csps probs) (define/contract (combine-csps probs)
((listof csp?) . -> . csp?) ((listof csp?) . -> . csp?)
@ -491,28 +493,17 @@
(apply append (map vars probs)) (apply append (map vars probs))
(apply append (map csp-constraints probs)))) (apply append (map csp-constraints probs))))
(define/contract (make-cartesian-generator solgens)
((listof generator?) . -> . generator?)
(generator ()
(define solstreams (for/list ([solgen (in-list solgens)])
(for/stream ([sol (in-producer solgen (void))])
sol)))
(let loop ([solstreams solstreams][sols empty])
(if (null? solstreams)
(yield (combine-csps (reverse sols)))
(for ([sol (in-stream (car solstreams))])
(loop (cdr solstreams) (cons sol sols)))))))
(define/contract (extract-subcsp prob names) (define/contract (extract-subcsp prob names)
(csp? (listof name?) . -> . csp?) (csp? (listof name?) . -> . csp?)
(make-csp (make-csp
(for/list ([vr (in-vars prob)] (for/list ([vr (in-vars prob)]
#:when (memq (var-name vr) names)) #:when (memq (var-name vr) names))
vr) vr)
(for/list ([const (in-constraints prob)] (for/list ([const (in-constraints prob)]
#:when (for/and ([cname (in-list (constraint-names const))]) #:when (for/and ([cname (in-list (constraint-names const))])
(memq cname names))) (memq cname names)))
const))) const)))
(define/contract (solve* prob (define/contract (solve* prob
#:finish-proc [finish-proc csp->assocs] #:finish-proc [finish-proc csp->assocs]
@ -525,12 +516,17 @@
(define subcsps ; decompose into independent csps. `cc` determines "connected components" (define subcsps ; decompose into independent csps. `cc` determines "connected components"
(if (current-decompose) (if (current-decompose)
(for/list ([nodeset (in-list (cc (csp->graph prob)))]) (for/list ([nodeset (in-list (cc (csp->graph prob)))])
(extract-subcsp prob nodeset)) (extract-subcsp prob nodeset))
(list prob))) (list prob)))
(define solgens (map solver subcsps))
(define solstreams (for/list ([solgen (in-list solgens)])
(for/stream ([sol (in-producer solgen (void))])
sol)))
(for/list ([solution (in-producer (make-cartesian-generator (map solver subcsps)) (void))] (for/list ([solution-pieces (in-cartesian solstreams)]
[idx (in-range max-solutions)]) [idx (in-range max-solutions)])
(finish-proc solution))) (finish-proc (combine-csps solution-pieces))))
(define/contract (solve prob (define/contract (solve prob
#:finish-proc [finish-proc csp->assocs] #:finish-proc [finish-proc csp->assocs]

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