Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / vrml-1.0.13 / proplan.m

diff --git a/octave_packages/vrml-1.0.13/proplan.m b/octave_packages/vrml-1.0.13/proplan.m
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+++ b/octave_packages/vrml-1.0.13/proplan.m
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+## Copyright (C) 2002 Etienne Grossmann <etienne@egdn.net>
+##
+## 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/>.
+
+##       x = proplan(x,d,v=1)
+##
+## orthogonally project x to the affine plane d*x == v
+
+function x = proplan(x,d,v)
+
+if exist("v")!=1, v = 1 ;end
+
+d = d(:) ;
+N = prod(size(d)) ;            # Assume x is NxP
+
+v = v/norm(d);
+d = d/norm(d);
+
+p = (v*d)*ones(1,size(x,2));
+
+x -= d*d'*(x-p) ;
+# x = p + (eye(N)-d*d')*(x-p) ;
+endfunction
+