Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / optim-1.2.0 / __bracket_min.m

diff --git a/octave_packages/optim-1.2.0/__bracket_min.m b/octave_packages/optim-1.2.0/__bracket_min.m
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+## Copyright (C) 2002 Etienne Grossmann <etienne@egdn.net>
+## Copyright (C) 2009 Levente Torok <TorokLev@gmail.com>
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## [a, b, ga, gb, nev] = semi_bracket (f, dx, a, narg, args)
+##
+## Find an interval containing a local minimum of the function 
+## g : h in reals ---> f (x+h*dx) where x = args{narg}
+##
+## a < b.
+## nev is the number of function evaluations
+
+function [a, b, ga, gb, n] = __bracket_min (f, dx, narg, args)
+
+    [a,b, ga,gb, n] = __semi_bracket (f, dx, 0, narg, args);
+
+    if a != 0, return; end
+
+    [a2,b2, ga2,gb2, n2] = __semi_bracket (f, -dx, 0, narg, args);
+
+    n += n2;
+
+    if a2 == 0,
+        a = -b2; ga = gb2;
+    else
+    a = -b2;
+    b = -a2;
+    ga = gb2;
+    gb = ga2;
+end