close Warning: Can't synchronize with repository "(default)" (The repository directory has changed, you should resynchronize the repository with: trac-admin $ENV repository resync '(default)'). Look in the Trac log for more information.

source: branches/f4grobner/criterion.lisp@ 787

Last change on this file since 787 was 484, checked in by Marek Rychlik, 9 years ago

* empty log message *

File size: 3.4 KB
Line 
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;;
24;; Pair selection criteria
25;;
26;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
27
28(defpackage "CRITERION"
29 (:use :cl :monomial :pair-queue :grobner-debug :polynomial)
30 (:export "CRITERION-1"
31 "CRITERION-2"
32 ))
33
34(in-package :criterion)
35
36(defun criterion-1 (pair)
37 "Returns T if the leading monomials of the two polynomials
38in G pointed to by the integers in PAIR have disjoint (relatively prime)
39monomials. This test is known as the first Buchberger criterion."
40 (declare (type pair pair))
41 (let ((f (pair-first pair))
42 (g (pair-second pair)))
43 (when (monom-rel-prime-p (poly-lm f) (poly-lm g))
44 (debug-cgb ":1")
45 (return-from criterion-1 t))))
46
47(defun criterion-2 (pair b-done partial-basis
48 &aux (f (pair-first pair)) (g (pair-second pair))
49 (place :before))
50 "Returns T if the leading monomial of some element P of
51PARTIAL-BASIS divides the LCM of the leading monomials of the two
52polynomials in the polynomial list PARTIAL-BASIS, and P paired with
53each of the polynomials pointed to by the the PAIR has already been
54treated, as indicated by the absence in the hash table B-done."
55 (declare (type pair pair) (type hash-table b-done)
56 (type poly f g))
57 ;; In the code below we assume that pairs are ordered as follows:
58 ;; if PAIR is (I J) then I appears before J in the PARTIAL-BASIS.
59 ;; We traverse the list PARTIAL-BASIS and keep track of where we
60 ;; are, so that we can produce the pairs in the correct order
61 ;; when we check whether they have been processed, i.e they
62 ;; appear in the hash table B-done
63 (dolist (h partial-basis nil)
64 (cond
65 ((eq h f)
66 #+grobner-check(assert (eq place :before))
67 (setf place :in-the-middle))
68 ((eq h g)
69 #+grobner-check(assert (eq place :in-the-middle))
70 (setf place :after))
71 ((and (monom-divides-monom-lcm-p (poly-lm h) (poly-lm f) (poly-lm g))
72 (gethash (case place
73 (:before (list h f))
74 ((:in-the-middle :after) (list f h)))
75 b-done)
76 (gethash (case place
77 ((:before :in-the-middle) (list h g))
78 (:after (list g h)))
79 b-done))
80 (debug-cgb ":2")
81 (return-from criterion-2 t)))))
Note: See TracBrowser for help on using the repository browser.