47 lines
1.1 KiB
Common Lisp
47 lines
1.1 KiB
Common Lisp
(defun 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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(defun 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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(setq prev g)
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(setq g (maplist identity g))
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(rplacd (last prev) prev))
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(rplacd (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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(rplaca a b)
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(setq a (cdr a))
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(setq b (cdr b))))
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l))
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(defun 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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(setq 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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(rplaca a b)
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(setq a (cdr a))
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(setq b (cdr b))))
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l))
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(time (progn (print (torus 100 100)) nil))
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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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