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source: branches/f4grobner/utils.lisp@ 82

Last change on this file since 82 was 82, checked in by Marek Rychlik, 9 years ago

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1;;; -*- Mode: Lisp; Package: Maxima; Syntax: Common-Lisp; Base: 10 -*-
2;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
3;;;
4;;; Copyright (C) 1999, 2002, 2009, 2015 Marek Rychlik <rychlik@u.arizona.edu>
5;;;
6;;; This program is free software; you can redistribute it and/or modify
7;;; it under the terms of the GNU General Public License as published by
8;;; the Free Software Foundation; either version 2 of the License, or
9;;; (at your option) any later version.
10;;;
11;;; This program is distributed in the hope that it will be useful,
12;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14;;; GNU General Public License for more details.
15;;;
16;;; You should have received a copy of the GNU General Public License
17;;; along with this program; if not, write to the Free Software
18;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19;;;
20;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
21
22
23;; Macros for making lists with iterators - an exammple of GENSYM
24;; MAKELIST-1 makes a list with one iterator, while MAKELIST accepts an
25;; arbitrary number of iterators
26
27;; Sample usage:
28;; Without a step:
29;; >(makelist-1 (* 2 i) i 0 10)
30;; (0 2 4 6 8 10 12 14 16 18 20)
31;; With a step of 3:
32;; >(makelist-1 (* 2 i) i 0 10 3)
33;; (0 6 12 18)
34
35;; Generate sums of squares of numbers between 1 and 4:
36;; >(makelist (+ (* i i) (* j j)) (i 1 4) (j 1 i))
37;; (2 5 8 10 13 18 17 20 25 32)
38;; >(makelist (list i j '---> (+ (* i i) (* j j))) (i 1 4) (j 1 i))
39;; ((1 1 ---> 2) (2 1 ---> 5) (2 2 ---> 8) (3 1 ---> 10) (3 2 ---> 13)
40;; (3 3 ---> 18) (4 1 ---> 17) (4 2 ---> 20) (4 3 ---> 25) (4 4 ---> 32))
41
42;; Evaluate expression expr with variable set to lo, lo+1,... ,hi
43;; and put the results in a list.
44(defmacro makelist-1 (expr var lo hi &optional (step 1))
45 (let ((l (gensym)))
46 `(do ((,var ,lo (+ ,var ,step))
47 (,l nil (cons ,expr ,l)))
48 ((> ,var ,hi) (reverse ,l))
49 (declare (fixnum ,var)))))
50
51(defmacro makelist (expr (var lo hi &optional (step 1)) &rest more)
52 (if (endp more)
53 `(makelist-1 ,expr ,var ,lo ,hi ,step)
54 (let* ((l (gensym)))
55 `(do ((,var ,lo (+ ,var ,step))
56 (,l nil (nconc ,l `,(makelist ,expr ,@more))))
57 ((> ,var ,hi) ,l)
58 (declare (fixnum ,var))))))
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