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* program to compute gears, with table
@ 2017-09-08  5:33 Emanuel Berg
  2017-09-08  8:46 ` Graham
                   ` (3 more replies)
  0 siblings, 4 replies; 29+ messages in thread
From: Emanuel Berg @ 2017-09-08  5:33 UTC (permalink / raw)
  To: help-gnu-emacs

Hey guys, does this look right to you?

;; (print-gears '(34 50) '(12 13 15 17 19 21 23 25) 622)
;;
;;                          =>
;;
;; 622 wheel
;;
;; chainring   sprocket   gear
;;
;;    34          25      2657.5360544880004
;;    34          23      2888.626146182609
;;    34          21      3163.7333982000005
;;    34          19      3496.7579664315795
;;    50          25      3908.1412566000004
;;    34          17      3908.1412566000004
;;    50          23      4247.97962673913
;;    34          15      4429.226757480001
;;    50          21      4652.549115000001
;;    34          13      5110.64625863077
;;    50          19      5142.291127105264
;;    34          12      5536.5334468500005
;;    50          17      5747.266553823531
;;    50          15      6513.568761
;;    50          13      7515.656262692309
;;    50          12      8141.960951250001

(require 'cl-lib)

(defun compute-gear (chainring sprocket wheel)
  (let*((pi     3.14159265)
        (radius (/ wheel 2.0))
        (circum (* 2 radius pi))
        (gear   (* (/ chainring sprocket 1.0) circum)))
    (list chainring sprocket gear)))

(defun gear (chainrings sprockets wheel)
  (let*((gears
         (cl-loop for c in chainrings
                  append (cl-loop for s in sprockets
                                  collect (compute-gear c s wheel) )
                  )))
        (cl-sort gears #'<= :key #'cl-caddr)))

(defun print-gears (chainrings sprockets wheel)
  (let ((out-buffer (get-buffer-create "*Gears*")))
    (with-current-buffer out-buffer
      (erase-buffer)
      (insert (format "%s wheel\n\n" wheel))
      (insert "chainring   sprocket   gear\n\n")
      (let ((gears (gear chainrings sprockets wheel)))
        (cl-loop for g in gears
                 do (let ((c (   car   g))
                          (s (   cadr  g))
                          (d (cl-caddr g)))
                      (insert (format "   %s          %s      %s\n" c s d)) ))))
    (pop-to-buffer out-buffer) ))

-- 
underground experts united
http://user.it.uu.se/~embe8573


^ permalink raw reply	[flat|nested] 29+ messages in thread

end of thread, other threads:[~2017-09-24  1:05 UTC | newest]

Thread overview: 29+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-09-08  5:33 program to compute gears, with table Emanuel Berg
2017-09-08  8:46 ` Graham
2017-09-08 15:50   ` Frank Krygowski
2017-09-08 21:56     ` Emanuel Berg
2017-09-08 17:44   ` Emanuel Berg
2017-09-08 11:09 ` Skip Montanaro
2017-09-08 11:27   ` tomas
2017-09-08 12:12     ` Skip Montanaro
2017-09-08 17:09 ` David Scheidt
2017-09-08 23:45   ` Emanuel Berg
     [not found] ` <mailman.158.1504868984.14750.help-gnu-emacs@gnu.org>
2017-09-08 17:52   ` Emanuel Berg
2017-09-08 19:56     ` Joerg
2017-09-08 19:59       ` David Scheidt
2017-09-08 23:55         ` Emanuel Berg
2017-09-09 19:17         ` Joerg
2017-09-09 19:46           ` Emanuel Berg
2017-09-10  2:06           ` David Scheidt
2017-09-10 14:59             ` Joerg
2017-09-23  5:42             ` DougC
2017-09-23  6:41               ` Emanuel Berg
2017-09-24  1:05               ` Joy Beeson
2017-09-11  5:02         ` Tosspot
2017-09-11  5:19           ` Emanuel Berg
2017-09-08 23:51       ` Emanuel Berg
2017-09-09 21:08       ` Tomas Nordin
2017-09-14 12:24       ` Stefan Monnier
2017-09-14 19:33         ` Tomas Nordin
2017-09-14 20:51           ` Emanuel Berg
2017-09-14 23:49           ` Nick Helm

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