From f4b44743d9546dbe42c109b2a25f25a1a51d8bbb Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Thu, 23 Jun 2011 16:53:52 +0200
Subject: [PATCH] maxima: Improved version of norm_2(), also rename to
 mat_norm2().

---
 maxima/maxima-init.mac | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/maxima/maxima-init.mac b/maxima/maxima-init.mac
index 045a258..f270c10 100644
--- a/maxima/maxima-init.mac
+++ b/maxima/maxima-init.mac
@@ -5,20 +5,15 @@
  */
 
 
-/* PACKAGES */
-
-/* Provides maxi() and mini() (and more). */
-load (descriptive);
-
-
 /* CUSTOM FUNCTIONS */
 
 /* Didn't find any euclid norm in Maxima, so here it is. */
 norm(x) := sqrt(transpose(x) . x);
 
-/* Maxima's norm() can't calculate the 2-norm. Only works for non-complex
- * matrices. */
-norm_2(x) := sqrt(maxi(eigenvalues(transpose(x) . x)[1]));
+/* Maxima's mat_norm() can't calculate the 2-norm. Thanks to Wolfgang Lindner
+ * (http://www.ma.utexas.edu/pipermail/maxima/2007/006300.html) for an
+ * improved version. */
+mat_norm2(x) := sqrt(lmax(eigenvalues(transpose(conjugate(x)).x)[1]));
 
 /* Shortcut to perform lu factorization. */
 lu(x) := block(x : lu_factor(x), get_lu_factors(x));
-- 
2.44.1