where to cut wood

[Emanuel Berg]

Where do you cut wood now that you aren't allowed to do that
in the machine shop anymore (or 'engineering workshop' to you
UK guys)?

The anser is <drumroll> at:

  l*n + (b/2)(2n - 1)

It's called algebra, as we see it works well with STATIC
entities! :))

;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/wood.el

(require 'cl-lib)

;; Where do you cut a piece of wood if the parts should be
;; length l and the blade is width b?
;;
;; For n cuts in n = 1, 2, ... the cuts should be at:
;;
;;   l*n + (b/2)(2n - 1)
;;
;; So for 3 parts of 60 cm each and a 3 mm blade cuts are made
;; at 60.15, 120.45 and 180.75 cm.

(defun cut-2 (len &optional num blade)
  (or blade (setq blade 0.3))
  (or num   (setq num 1))
  (when (> num 0)
    (let ((hb (/ blade 2.0) ))
      (+ (* len num)
         (* hb (1- (* 2 num))) ))))
;; (cut-2 60 1) ;  60.15
;; (cut-2 60 2) ; 120.45
;; (cut-2 60 3) ; 180.75

(defun cut (len &optional blade n)
  (or blade (setq blade 0.3))
  (or n     (setq n 3))
  (cl-loop repeat n
    with cuts
    with pos = 0
    with hb  = (/ blade 2.0)
    do (cl-incf pos (+ len hb))
       (push pos cuts)
       (cl-incf pos hb)
    finally return (nreverse cuts)) )
;; (cut 60) ; (60.15 120.45 180.75)

-- 
underground experts united
https://dataswamp.org/~incal