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author | William Carroll <wpcarro@gmail.com> | 2019-10-09T11·13+0100 |
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committer | William Carroll <wpcarro@gmail.com> | 2019-12-24T15·21+0000 |
commit | 6b456c1b7a4f6899f063a6e65355af51901d9c7a (patch) | |
tree | cfc70d74818ae9fabdbbfb0cf16cce092e4c1a09 /configs/shared/.emacs.d/wpc/series.el | |
parent | a7c72adb2ebec1e497fc040eaf3551d564d61a5b (diff) |
Massive configuration overhaul
Currently paying the price of months of non-diligent git usage. Here's what has changed. - Theming support in Gvcci and wpgtk - Dropping support for i3 - Supporting EXWM - Many Elisp modules - Collapsed redundant directories in ./configs
Diffstat (limited to 'configs/shared/.emacs.d/wpc/series.el')
-rw-r--r-- | configs/shared/.emacs.d/wpc/series.el | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/configs/shared/.emacs.d/wpc/series.el b/configs/shared/.emacs.d/wpc/series.el new file mode 100644 index 000000000000..977ffc50261a --- /dev/null +++ b/configs/shared/.emacs.d/wpc/series.el @@ -0,0 +1,81 @@ +;;; series.el --- Hosting common series of numbers -*- lexical-binding: t -*- +;; Author: William Carroll <wpcarro@gmail.com> + +;;; Commentary: +;; Encoding number series as I learn about them. +;; +;; These are the following series I'm interested in supporting: +;; - Fibonacci +;; - Catalan numbers +;; - Figurate number series +;; - Triangular +;; - Square +;; - Pentagonal +;; - Hexagonal +;; - Lazy-caterer +;; - Magic square +;; - Look-and-say + +;;; Code: + +(require 'number) + +(defun series/range (beg end) + "Create a list of numbers from `BEG' to `END'. +This is an inclusive number range." + (if (< end beg) + (list/reverse + (number-sequence end beg)) + (number-sequence beg end))) + +(defun series/fibonacci-number (i) + "Return the number in the fibonacci series at `I'." + (cond + ((= 0 i) 0) + ((= 1 i) 1) + (t (+ (series/fibonacci-number (- i 1)) + (series/fibonacci-number (- i 2)))))) + +(defun series/fibonacci (n) + "Return the first `N' numbers of the fibonaccci series starting at zero." + (if (= 0 n) + '() + (list/reverse + (list/cons (series/fibonacci-number (number/dec n)) + (list/reverse + (series/fibonacci (number/dec n))))))) + +;; TODO: Consider memoization. +(defun series/triangular-number (i) + "Return the number in the triangular series at `I'." + (if (= 0 i) + 0 + (+ i (series/triangular-number (number/dec i))))) + +;; TODO: Improve performance. +;; TODO: Consider creating a stream protocol with `stream/next' and implement +;; this using that. +(defun series/triangular (n) + "Return the first `N' numbers of a triangular series starting at 0." + (if (= 0 n) + '() + (list/reverse + (list/cons (series/triangular-number (number/dec n)) + (list/reverse + (series/triangular (number/dec n))))))) + +(defun series/catalan-number (i) + "Return the catalan number in the series at `I'." + (if (= 0 i) + 1 + (/ (number/factorial (* 2 i)) + (* (number/factorial (number/inc i)) + (number/factorial i))))) + +(defun series/catalan (n) + "Return the first `N' numbers in a catalan series." + (->> (series/range 0 (number/dec n)) + (list/map #'series/catalan-number))) + +(provide 'series) +;;; series.el ends here |