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@ -20,7 +20,7 @@
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(if (null? argss)
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(yield (reverse acc))
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(for ([arg (car argss)])
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(loop (cdr argss) (cons arg acc))))))))
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(loop (cdr argss) (cons arg acc))))))))
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(struct csp (vars constraints) #:mutable #:transparent)
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(define constraints csp-constraints)
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@ -36,7 +36,7 @@
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(raise-argument-error 'constraint "csp" prob))
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;; apply proc in many-to-many style
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(for/and ([args (in-cartesian (map (λ (name) (find-domain prob name)) (constraint-names const)))])
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(apply (constraint-proc const) args))))
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(apply (constraint-proc const) args))))
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(define name? symbol?)
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@ -97,11 +97,11 @@
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((csp? procedure? (listof (listof name?))) ((or/c #false name?)) . ->* . void?)
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(set-csp-constraints! prob (append (constraints prob)
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(for/list ([names (in-list namess)])
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(for ([name (in-list names)])
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(check-name-in-csp! 'add-constraints! prob name))
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(make-constraint names (if proc-name
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(procedure-rename proc proc-name)
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proc))))))
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(for ([name (in-list names)])
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(check-name-in-csp! 'add-constraints! prob name))
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(make-constraint names (if proc-name
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(procedure-rename proc proc-name)
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proc))))))
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(define/contract (add-pairwise-constraint! prob proc names [proc-name #false])
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((csp? procedure? (listof name?)) (name?) . ->* . void?)
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@ -140,7 +140,7 @@
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(check-name-in-csp! 'find-var prob name)
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(for/first ([vr (in-vars prob)]
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#:when (eq? name (var-name vr)))
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vr))
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vr))
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(define/contract (find-domain prob name)
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(csp? name? . -> . (listof any/c))
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@ -183,20 +183,20 @@
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(ormap assigned? (constraint-names constraint)))
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(make-csp (vars prob)
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(for/list ([const (in-constraints prob)])
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(cond
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;; no point reducing 2-arity functions because they will be consumed by forward checking
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[(and (or (not minimum-arity) (<= minimum-arity (constraint-arity const)))
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(partially-assigned? const))
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(match-define (constraint cnames proc) const)
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;; pattern is mix of values and boxed symbols (indicating variables to persist)
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;; use boxes here as cheap way to distinguish id symbols from value symbols
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(define arity-reduction-pattern (for/list ([cname (in-list cnames)])
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(if (assigned? cname)
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(first (find-domain prob cname))
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(box cname))))
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(constraint (filter-not assigned? cnames)
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(reduce-function-arity proc arity-reduction-pattern))]
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[else const]))))
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(cond
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|
;; no point reducing 2-arity functions because they will be consumed by forward checking
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[(and (or (not minimum-arity) (<= minimum-arity (constraint-arity const)))
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(partially-assigned? const))
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(match-define (constraint cnames proc) const)
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;; pattern is mix of values and boxed symbols (indicating variables to persist)
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|
;; use boxes here as cheap way to distinguish id symbols from value symbols
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|
(define arity-reduction-pattern (for/list ([cname (in-list cnames)])
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|
(if (assigned? cname)
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|
(first (find-domain prob cname))
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|
(box cname))))
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|
(constraint (filter-not assigned? cnames)
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(reduce-function-arity proc arity-reduction-pattern))]
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|
[else const]))))
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|
(define nassns 0)
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|
(define nfchecks 0)
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|
@ -211,9 +211,9 @@
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|
(begin0
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|
(make-csp
|
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|
(for/list ([vr (in-vars prob)])
|
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|
(if (eq? name (var-name vr))
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|
(assigned-var name (list val))
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vr))
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|
(if (eq? name (var-name vr))
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|
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|
(assigned-var name (list val))
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|
vr))
|
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|
|
(constraints prob))
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|
(when-debug (set! nassns (add1 nassns)))))
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|
@ -243,7 +243,7 @@
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|
(for/list ([x (in-list xs)]
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|
[val (in-list vals)]
|
|
|
|
|
#:when (= val target-val))
|
|
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|
|
x)]))
|
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|
x)]))
|
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|
|
|
(define/contract (argmax* proc xs)
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|
(procedure? (listof any/c) . -> . (listof any/c))
|
|
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|
|
@ -268,7 +268,7 @@
|
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|
(csp? var? . -> . natural?)
|
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|
|
(for/sum ([const (in-constraints prob)]
|
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|
|
|
#:when (memq (var-name var) (constraint-names const)))
|
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|
|
|
1))
|
|
|
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|
1))
|
|
|
|
|
|
|
|
|
|
(define/contract (domain-length var)
|
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|
|
|
(var? . -> . natural?)
|
|
|
|
|
@ -277,7 +277,7 @@
|
|
|
|
|
(define/contract (state-count csp)
|
|
|
|
|
(csp? . -> . natural?)
|
|
|
|
|
(for/product ([vr (in-vars csp)])
|
|
|
|
|
(domain-length vr)))
|
|
|
|
|
(domain-length vr)))
|
|
|
|
|
|
|
|
|
|
(define/contract (mrv-degree-hybrid prob)
|
|
|
|
|
(csp? . -> . (or/c #f var?))
|
|
|
|
|
@ -296,8 +296,8 @@
|
|
|
|
|
[cnames (in-value (constraint-names const))]
|
|
|
|
|
#:when (and (= (length names) (length cnames))
|
|
|
|
|
(for/and ([name (in-list names)])
|
|
|
|
|
(memq name cnames))))
|
|
|
|
|
const))
|
|
|
|
|
(memq name cnames))))
|
|
|
|
|
const))
|
|
|
|
|
|
|
|
|
|
(define (one-arity? const) (= 1 (constraint-arity const)))
|
|
|
|
|
(define (two-arity? const) (= 2 (constraint-arity const)))
|
|
|
|
|
@ -311,7 +311,7 @@
|
|
|
|
|
((listof (and/c constraint? two-arity?)) . -> . (listof arc?))
|
|
|
|
|
(for*/list ([const (in-list constraints)]
|
|
|
|
|
[name (in-list (constraint-names const))])
|
|
|
|
|
(arc name const)))
|
|
|
|
|
(arc name const)))
|
|
|
|
|
|
|
|
|
|
(require sugar/debug)
|
|
|
|
|
(define/contract (reduce-domain prob ark)
|
|
|
|
|
@ -323,16 +323,16 @@
|
|
|
|
|
(λ (val other-val) (constraint-proc other-val val)))) ; otherwise reverse arg order
|
|
|
|
|
(define (satisfies-arc? val)
|
|
|
|
|
(for/or ([other-val (in-list (find-domain prob other-name))])
|
|
|
|
|
(proc val other-val)))
|
|
|
|
|
(proc val other-val)))
|
|
|
|
|
(make-csp
|
|
|
|
|
(for/list ([vr (in-vars prob)])
|
|
|
|
|
(cond
|
|
|
|
|
[(assigned-var? vr) vr]
|
|
|
|
|
[(eq? name (var-name vr))
|
|
|
|
|
(make-var name (match (filter satisfies-arc? (domain vr))
|
|
|
|
|
[(? empty?) (backtrack!)]
|
|
|
|
|
[vals vals]))]
|
|
|
|
|
[else vr]))
|
|
|
|
|
(cond
|
|
|
|
|
[(assigned-var? vr) vr]
|
|
|
|
|
[(eq? name (var-name vr))
|
|
|
|
|
(make-var name (match (filter satisfies-arc? (domain vr))
|
|
|
|
|
[(? empty?) (backtrack!)]
|
|
|
|
|
[vals vals]))]
|
|
|
|
|
[else vr]))
|
|
|
|
|
(constraints prob)))
|
|
|
|
|
|
|
|
|
|
(define/contract (terminating-at? arcs name)
|
|
|
|
|
@ -341,7 +341,7 @@
|
|
|
|
|
#:when (and
|
|
|
|
|
(memq name (constraint-names (arc-const arc)))
|
|
|
|
|
(not (eq? name (arc-name arc)))))
|
|
|
|
|
arc))
|
|
|
|
|
arc))
|
|
|
|
|
|
|
|
|
|
(define/contract (ac-3 prob ref-name)
|
|
|
|
|
(csp? name? . -> . csp?)
|
|
|
|
|
@ -351,8 +351,8 @@
|
|
|
|
|
(define starting-arcs (two-arity-constraints->arcs (for/list ([const (in-constraints prob)]
|
|
|
|
|
#:when (and (two-arity? const)
|
|
|
|
|
(for/and ([cname (in-list (constraint-names const))])
|
|
|
|
|
(memq cname checkable-names))))
|
|
|
|
|
const)))
|
|
|
|
|
(memq cname checkable-names))))
|
|
|
|
|
const)))
|
|
|
|
|
(for/fold ([prob prob]
|
|
|
|
|
[arcs (sort starting-arcs < #:key (λ (a) (length (find-domain prob (arc-name a)))) #:cache-keys? #true)]
|
|
|
|
|
#:result (prune-singleton-constraints prob))
|
|
|
|
|
@ -383,11 +383,11 @@
|
|
|
|
|
(define new-vals
|
|
|
|
|
(for/list ([val (in-list vals)]
|
|
|
|
|
#:when (for/and ([const (in-list constraints)])
|
|
|
|
|
(let ([proc (constraint-proc const)])
|
|
|
|
|
(if (eq? name (first (constraint-names const)))
|
|
|
|
|
(proc val ref-val)
|
|
|
|
|
(proc ref-val val)))))
|
|
|
|
|
val))
|
|
|
|
|
(let ([proc (constraint-proc const)])
|
|
|
|
|
(if (eq? name (first (constraint-names const)))
|
|
|
|
|
(proc val ref-val)
|
|
|
|
|
(proc ref-val val)))))
|
|
|
|
|
val))
|
|
|
|
|
(checked-variable name new-vals (cons (cons ref-name ref-val) (match vr
|
|
|
|
|
[(checked-variable _ _ history) history]
|
|
|
|
|
[else null])))])]))
|
|
|
|
|
@ -396,15 +396,15 @@
|
|
|
|
|
((csp?) ((or/c #false name?)) . ->* . csp?)
|
|
|
|
|
(define singleton-var-names (for/list ([vr (in-vars prob)]
|
|
|
|
|
#:when (singleton-var? vr))
|
|
|
|
|
(var-name vr)))
|
|
|
|
|
(var-name vr)))
|
|
|
|
|
(make-csp
|
|
|
|
|
(vars prob)
|
|
|
|
|
(for/list ([const (in-constraints prob)]
|
|
|
|
|
#:unless (and (two-arity? const)
|
|
|
|
|
(or (not ref-name) (constraint-relates? const ref-name))
|
|
|
|
|
(for/and ([cname (in-list (constraint-names const))])
|
|
|
|
|
(memq cname singleton-var-names))))
|
|
|
|
|
const)))
|
|
|
|
|
(memq cname singleton-var-names))))
|
|
|
|
|
const)))
|
|
|
|
|
|
|
|
|
|
(define/contract (forward-check prob ref-name)
|
|
|
|
|
(csp? name? . -> . csp?)
|
|
|
|
|
@ -413,7 +413,7 @@
|
|
|
|
|
;; conflict-set will be empty if there are no empty domains (as we would hope)
|
|
|
|
|
(define conflict-set (for/list ([cvr (in-list checked-vars)]
|
|
|
|
|
#:when (empty? (domain cvr)))
|
|
|
|
|
(history cvr)))
|
|
|
|
|
(history cvr)))
|
|
|
|
|
;; for conflict-directed backjumping it's essential to forward-check ALL vars
|
|
|
|
|
;; (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.
|
|
|
|
|
@ -430,7 +430,7 @@
|
|
|
|
|
;; constraint is checkable if all constraint names
|
|
|
|
|
;; are in target list of names.
|
|
|
|
|
(for/and ([cname (in-list (constraint-names const))])
|
|
|
|
|
(memq cname names)))
|
|
|
|
|
(memq cname names)))
|
|
|
|
|
|
|
|
|
|
(define/contract (constraint-arity const)
|
|
|
|
|
(constraint? . -> . natural?)
|
|
|
|
|
@ -447,21 +447,21 @@
|
|
|
|
|
(partition (λ (const) (and (constraint-checkable? const assigned-varnames)
|
|
|
|
|
(or (not mandatory-names)
|
|
|
|
|
(for/and ([name (in-list mandatory-names)])
|
|
|
|
|
(constraint-relates? const name)))))
|
|
|
|
|
(constraint-relates? const name)))))
|
|
|
|
|
(constraints prob)))
|
|
|
|
|
(cond
|
|
|
|
|
[conflict-count?
|
|
|
|
|
(define conflict-count
|
|
|
|
|
(for/sum ([constraint (in-list checkable-consts)]
|
|
|
|
|
#:unless (constraint prob))
|
|
|
|
|
1))
|
|
|
|
|
1))
|
|
|
|
|
(when-debug (set! nchecks (+ conflict-count nchecks)))
|
|
|
|
|
conflict-count]
|
|
|
|
|
[else
|
|
|
|
|
(for ([(constraint idx) (in-indexed checkable-consts)]
|
|
|
|
|
#:unless (constraint prob))
|
|
|
|
|
(when-debug (set! nchecks (+ (add1 idx) nchecks)))
|
|
|
|
|
(backtrack!))
|
|
|
|
|
(when-debug (set! nchecks (+ (add1 idx) nchecks)))
|
|
|
|
|
(backtrack!))
|
|
|
|
|
;; discard checked constraints, since they have no further reason to live
|
|
|
|
|
(make-csp (vars prob) other-consts)]))
|
|
|
|
|
|
|
|
|
|
@ -473,19 +473,19 @@
|
|
|
|
|
prob
|
|
|
|
|
(make-csp
|
|
|
|
|
(for/list ([vr (in-vars prob)])
|
|
|
|
|
(match-define (var name vals) vr)
|
|
|
|
|
(define name-constraints (filter (λ (const) (constraint-relates? const name)) unary-constraints))
|
|
|
|
|
(make-var name (for/list ([val (in-list vals)]
|
|
|
|
|
#:when (for/and ([const (in-list name-constraints)])
|
|
|
|
|
((constraint-proc const) val)))
|
|
|
|
|
val)))
|
|
|
|
|
(match-define (var name vals) vr)
|
|
|
|
|
(define name-constraints (filter (λ (const) (constraint-relates? const name)) unary-constraints))
|
|
|
|
|
(make-var name (for/list ([val (in-list vals)]
|
|
|
|
|
#:when (for/and ([const (in-list name-constraints)])
|
|
|
|
|
((constraint-proc const) val)))
|
|
|
|
|
val)))
|
|
|
|
|
other-constraints)))
|
|
|
|
|
|
|
|
|
|
(define ((make-hist-proc assocs) . xs)
|
|
|
|
|
(not
|
|
|
|
|
(for/and ([x (in-list xs)]
|
|
|
|
|
[val (in-list (map cdr assocs))])
|
|
|
|
|
(equal? x val))))
|
|
|
|
|
(equal? x val))))
|
|
|
|
|
|
|
|
|
|
(define/contract (backtracking-solver
|
|
|
|
|
prob
|
|
|
|
|
@ -506,7 +506,7 @@
|
|
|
|
|
(and (backtrack? exn) (or (let ([bths (backtrack-histories exn)])
|
|
|
|
|
(or (empty? bths) (for*/or ([bth bths]
|
|
|
|
|
[rec bth])
|
|
|
|
|
(eq? name (car rec))))))))
|
|
|
|
|
(eq? name (car rec))))))))
|
|
|
|
|
(for/fold ([conflicts null]
|
|
|
|
|
#:result (void))
|
|
|
|
|
([val (in-list (order-domain-values domain))])
|
|
|
|
|
@ -516,15 +516,17 @@
|
|
|
|
|
(append conflicts (remq name (remove-duplicates
|
|
|
|
|
(for*/list ([bth bths]
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[rec bth])
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(car rec)) eq?))))])
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(car rec)) eq?))))])
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(let* ([prob (assign-val prob name val)]
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;; reduce constraints before inference,
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;; to create more forward-checkable (binary) constraints
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[prob (reduce-arity-proc prob)]
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[prob (inference prob name)]
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[prob (check-constraints prob)])
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(loop prob)))
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conflicts)]))))
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(loop prob))
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;; conflicts goes inside the handler expression
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;; so raises can supersede it
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conflicts))]))))
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(define/contract (random-pick xs)
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((non-empty-listof any/c) . -> . any/c)
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@ -556,9 +558,9 @@
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((csp?) (integer?) . ->* . generator?)
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(generator ()
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(for ([thread-count (or (current-thread-count) 1)]) ; todo: what is ideal thread count?
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(make-min-conflcts-thread prob thread-count max-steps))
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(make-min-conflcts-thread prob thread-count max-steps))
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(for ([i (in-naturals)])
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(yield (thread-receive)))))
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(yield (thread-receive)))))
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(define/contract (optimal-stop-min proc xs)
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(procedure? (listof any/c) . -> . any/c)
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@ -566,7 +568,7 @@
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(define threshold (argmin proc sample))
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(or (for/first ([candidate (in-list candidates)]
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#:when (<= (proc candidate) threshold))
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candidate)
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candidate)
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(last candidates)))
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(define/contract (conflicted-variable-names prob)
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@ -574,7 +576,7 @@
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;; Return a list of variables in current assignment that are conflicted
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(for/list ([name (in-var-names prob)]
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#:when (positive? (nconflicts prob name)))
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name))
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name))
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(define/contract (min-conflicts-value prob name vals)
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(csp? name? (listof any/c) . -> . any/c)
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@ -583,7 +585,7 @@
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#:cache-keys? #true))
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(for/first ([val (in-list vals-by-conflict)]
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#:unless (equal? val (first (find-domain prob name)))) ;; but change the value
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val))
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val))
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(define no-value-sig (gensym))
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@ -598,11 +600,11 @@
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((csp?) ((listof name?)) . ->* . (listof (cons/c name? any/c)))
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|
(define assocs
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|
(for/list ([vr (in-vars prob)])
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|
(match vr
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|
[(var name (list val)) (cons name val)])))
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|
(match vr
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|
[(var name (list val)) (cons name val)])))
|
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|
(if keys
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|
(for/list ([key (in-list keys)])
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|
(assq key assocs))
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|
|
(assq key assocs))
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|
|
assocs))
|
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|
|
(define/contract (combine-csps probs)
|
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|
|
|
@ -617,11 +619,11 @@
|
|
|
|
|
(make-csp
|
|
|
|
|
(for/list ([vr (in-vars prob)]
|
|
|
|
|
#:when (memq (var-name vr) names))
|
|
|
|
|
vr)
|
|
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|
|
vr)
|
|
|
|
|
(for/list ([const (in-constraints prob)]
|
|
|
|
|
#:when (for/and ([cname (in-list (constraint-names const))])
|
|
|
|
|
(memq cname names)))
|
|
|
|
|
const)))
|
|
|
|
|
(memq cname names)))
|
|
|
|
|
const)))
|
|
|
|
|
|
|
|
|
|
(define/contract (solve* prob
|
|
|
|
|
#:finish-proc [finish-proc (λ (p) (csp->assocs p (map var-name (vars prob))))]
|
|
|
|
|
@ -634,17 +636,17 @@
|
|
|
|
|
(define subcsps ; decompose into independent csps. `cc` determines "connected components"
|
|
|
|
|
(if (current-decompose)
|
|
|
|
|
(for/list ([nodeset (in-list (cc (csp->graph prob)))])
|
|
|
|
|
(extract-subcsp prob nodeset))
|
|
|
|
|
(extract-subcsp prob nodeset))
|
|
|
|
|
(list prob)))
|
|
|
|
|
|
|
|
|
|
(define solgens (map solver subcsps))
|
|
|
|
|
(define solstreams (for/list ([solgen (in-list solgens)])
|
|
|
|
|
(for/stream ([sol (in-producer solgen (void))])
|
|
|
|
|
sol)))
|
|
|
|
|
(for/stream ([sol (in-producer solgen (void))])
|
|
|
|
|
sol)))
|
|
|
|
|
|
|
|
|
|
(for/list ([solution-pieces (in-cartesian solstreams)]
|
|
|
|
|
[idx (in-range max-solutions)])
|
|
|
|
|
(finish-proc (combine-csps solution-pieces))))
|
|
|
|
|
(finish-proc (combine-csps solution-pieces))))
|
|
|
|
|
|
|
|
|
|
(define/contract (solve prob
|
|
|
|
|
#:finish-proc [finish-proc (λ (p) (csp->assocs p (map var-name (vars prob))))]
|
|
|
|
|
|
