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| | ;; -*- lexical-binding: t; -*-
;; Copyright (C) 2019 Free Software Foundation, Inc.
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Adapted to elisp from CL version from:
;; https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
;; Compute pi
(require 'cl-lib)
(defvar elb-acc)
(defvar elb-den)
(defvar elb-num)
(defun elb-extract-digit (nth)
(truncate (+ (* elb-num nth) elb-acc) elb-den))
(defun elb-eliminate-digit (d)
(cl-decf elb-acc (* elb-den d))
(setf elb-acc (* elb-acc 10)
elb-num (* elb-num 10)))
(defun elb-next-term (k)
(let ((k2 (1+ (* k 2))))
(cl-incf elb-acc (* elb-num 2))
(setf elb-acc (* elb-acc k2)
elb-den (* elb-den k2)
elb-num (* elb-num k))))
(defun elb-pidigits (x)
(let ((elb-acc 0)
(elb-den 1)
(elb-num 1)
(res ()))
(cl-do ((d 0) (k 0) (i 0) (n 10000))
((>= i n))
(setf n x)
(elb-next-term (cl-incf k))
(unless (> elb-num elb-acc)
(setf d (elb-extract-digit 3))
(unless (/= d (elb-extract-digit 4))
(push d res)
(cl-incf i)
;; (when (= (mod (cl-incf i) 10) 0)
;; (message "%d" i))
(elb-eliminate-digit d))))
(reverse res)))
(defun elb-pidigits-entry ()
(cl-loop repeat 1000
do (elb-pidigits 500)))
(provide 'elb-pidigits)
|