Improve graph isomorphism detection

Julien LepillerWed Apr 08 01:25:01+0200 2020

af8fcd6

Improve graph isomorphism detection

rdf/rdf.scm

339339 
  (match constraints
340340 
    (('equiv b1 b2) (list (list (cons b1 b2))))
341341 
    ('none (list (list)))
342+
    ('bot 'bot)
342343 
    (('or e1 e2)
343-
     (cond
344-
       ((equal? e2 'bot)
345-
        (to-disjunctions e1))
346-
       ((equal? e1 'bot)
347-
        (to-disjunctions e2))
348-
       (else
349-
         (let ((e1 (to-disjunctions e1))
350-
               (e2 (to-disjunctions e2)))
344+
     (let ((e1 (to-disjunctions e1))
345+
           (e2 (to-disjunctions e2)))
346+
       (cond
347+
         ((equal? e2 'bot)
348+
          e1)
349+
         ((equal? e1 'bot)
350+
          e2)
351+
         (else
351352 
           (append e1 e2)))))
352353 
    (('and e1 e2)
353-
     (cond
354-
       ((equal? e1 'bot)
355-
        'bot)
356-
       ((equal? e2 'bot)
357-
        'bot)
358-
       (else
359-
         (let ((e1 (to-disjunctions e1))
360-
               (e2 (to-disjunctions e2)))
354+
     (let ((e1 (to-disjunctions e1))
355+
           (e2 (to-disjunctions e2)))
356+
       (cond
357+
         ((equal? e1 'bot)
358+
          'bot)
359+
         ((equal? e2 'bot)
360+
          'bot)
361+
         (else
361362 
           (merge-joins e1 e2)))))))
362363 
363364 
(define (generate-triple-constraints t1 t2)
…
425426 
  "Compare two graphs and return whether they are isomorph."
426427 
  (let* ((constraints (generate-graph-constraints g1 g2))
427428 
         (disjunctions (to-disjunctions constraints)))
428-
    (let loop ((disjunctions (filter sat? disjunctions)))
429-
      (match disjunctions
430-
        ('() (and (null? g1) (null? g2)))
431-
        ((mapping disjunctions ...)
432-
         (if (and (validate-mapping mapping g1 g2)
433-
                  (validate-mapping (reverse-mapping mapping) g2 g1))
434-
           #t
435-
           (loop disjunctions)))))))
429+
    (if (list? disjunctions)
430+
        (let loop ((disjunctions (filter sat? disjunctions)))
431+
          (match disjunctions
432+
            ('() (and (null? g1) (null? g2)))
433+
            ((mapping disjunctions ...)
434+
             (if (and (validate-mapping mapping g1 g2)
435+
                      (validate-mapping (reverse-mapping mapping) g2 g1))
436+
               #t
437+
               (loop disjunctions)))))
438+
        #f)))
436439 
437440 
(define (generate-dataset-constraints d1 d2)
438441 
  (let ((g1 (rdf-dataset-default-graph d1))
…
480483 
  "Compare two datasets and return whether they are isomorphic."
481484 
  (let* ((constraints (generate-dataset-constraints d1 d2))
482485 
         (disjunctions (to-disjunctions constraints)))
483-
    (let loop ((disjuctions (filter sat? disjunctions)))
484-
      (match disjunctions
485-
        ('() (and (null? (rdf-dataset-default-graph d1))
486-
                  (null? (rdf-dataset-default-graph d2))
487-
                  (null? (rdf-dataset-named-graphs d1))
488-
                  (null? (rdf-dataset-named-graphs d2))))
489-
        ((mapping disjunctions ...)
490-
         (or (and (validate-dataset-mapping mapping d1 d2)
491-
                  (validate-dataset-mapping (reverse-mapping mapping) d2 d1))
492-
             (loop disjunctions)))))))
486+
    (if (list? disjunctions)
487+
        (let loop ((disjunctions (filter sat? disjunctions)))
488+
          (match disjunctions
489+
            ('() (and (null? (rdf-dataset-default-graph d1))
490+
                      (null? (rdf-dataset-default-graph d2))
491+
                      (null? (rdf-dataset-named-graphs d1))
492+
                      (null? (rdf-dataset-named-graphs d2))))
493+
            ((mapping disjunctions ...)
494+
             (or (and (validate-dataset-mapping mapping d1 d2)
495+
                      (validate-dataset-mapping (reverse-mapping mapping) d2 d1))
496+
                 (loop disjunctions)))))
497+
        #f)))
493498 
494499 
;; Recognizing datatypes is a transformation on the graph to add the proper
495500 
;; datatype to literals, and replace IRIs that represent a datatype with the