Update copyright year to 2015

[gnu-emacs] / lisp / calc / calc-mtx.el

diff --git a/lisp/calc/calc-mtx.el b/lisp/calc/calc-mtx.el
index dd8ad0c8164d13e6f8cf8e4a5f813477e09c34ed..b8c5ff910933750507db46f6ab103bf68b770c41 100644 (file)
--- a/lisp/calc/calc-mtx.el
+++ b/lisp/calc/calc-mtx.el
@@ -1,17 +1,16 @@
 ;;; calc-mtx.el --- matrix functions for Calc
 
-;; Copyright (C) 1990, 1991, 1992, 1993, 2001, 2002, 2003, 2004,
-;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+;; Copyright (C) 1990-1993, 2001-2015 Free Software Foundation, Inc.
 
 ;; Author: David Gillespie <daveg@synaptics.com>
 ;; Maintainer: Jay Belanger <jay.p.belanger@gmail.com>
 
 ;; This file is part of GNU Emacs.
 
-;; GNU Emacs is free software; you can redistribute it and/or modify
+;; 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, or (at your option)
-;; any later version.
+;; 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
@@ -19,9 +18,7 @@
 ;; GNU General Public License for more details.
 
 ;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING.  If not, write to the
-;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-;; Boston, MA 02110-1301, USA.
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
 
 ;;; Commentary:
 
@@ -235,6 +232,20 @@
          (setq math-lud-cache (cons (cons m entry) math-lud-cache)))
        lud))))
 
+
+(defun math-lud-pivot-check (a)
+  "Determine a useful value for checking the size of potential pivots
+in LUD decomposition."
+  (cond ((eq (car-safe a) 'mod)
+         (if (and (math-integerp (nth 1 a))
+                  (math-integerp (nth 2 a))
+                  (eq (math-gcd (nth 1 a) (nth 2 a)) 1))
+             1
+           0))
+        (t
+         (math-abs-approx a))))
+
+
 ;;; Numerical Recipes section 2.3; implicit pivoting omitted.
 (defun math-do-matrix-lud (m)
   (let* ((lu (math-copy-matrix m))
@@ -264,7 +275,7 @@
                                            (nth j (nth k lu))))
                k (1+ k)))
        (setcar (nthcdr j (nth i lu)) sum)
-       (let ((dum (math-abs-approx sum)))
+       (let ((dum (math-lud-pivot-check sum)))
          (if (Math-lessp big dum)
              (setq big dum
                    imax i)))
@@ -367,5 +378,4 @@
 
 (provide 'calc-mtx)
 
-;;; arch-tag: fc0947b1-90e1-4a23-8950-d8ead9c3a306
 ;;; calc-mtx.el ends here