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