ref: b09398e98563c23b6988e77b7b5ab84c0e03ceb7
dir: /test/torus.lsp/
; -*- scheme -*- (define (maplist f l) (if (null? l) () (cons (f l) (maplist f (cdr l))))) ; produce a beautiful, toroidal cons structure ; make m copies of a CDR-circular list of length n, and connect corresponding ; conses in CAR-circular loops ; replace maplist 'identity' with 'copy-tree' for rapdily exploding memory use (define (torus m n) (let* ((l (map-int identity n)) (g l) (prev g)) (dotimes (i (- m 1)) (set! prev g) (set! g (maplist identity g)) (set-cdr! (last-pair prev) prev)) (set-cdr! (last-pair g) g) (let ((a l) (b g)) (dotimes (i n) (set-car! a b) (set! a (cdr a)) (set! b (cdr b)))) l)) (define (cyl m n) (let* ((l (map-int identity n)) (g l)) (dotimes (i (- m 1)) (set! g (maplist identity g))) (let ((a l) (b g)) (dotimes (i n) (set-car! a b) (set! a (cdr a)) (set! b (cdr b)))) l)) (time (begin (print (torus 100 100)) ())) ;(time (dotimes (i 1) (load "100x100.lsp"))) ; with ltable ; printing time: 0.415sec ; reading time: 0.165sec ; with ptrhash ; printing time: 0.081sec ; reading time: 0.0264sec