Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / geom2d / vectorNorm.m

diff --git a/octave_packages/geometry-1.5.0/geom2d/vectorNorm.m b/octave_packages/geometry-1.5.0/geom2d/vectorNorm.m
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+++ b/octave_packages/geometry-1.5.0/geom2d/vectorNorm.m
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+%% Copyright (c) 2011, INRA
+%% 2007-2011, David Legland <david.legland@grignon.inra.fr>
+%% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+%%
+%% All rights reserved.
+%% (simplified BSD License)
+%%
+%% Redistribution and use in source and binary forms, with or without
+%% modification, are permitted provided that the following conditions are met:
+%%
+%% 1. Redistributions of source code must retain the above copyright notice, this
+%%    list of conditions and the following disclaimer.
+%%     
+%% 2. Redistributions in binary form must reproduce the above copyright notice, 
+%%    this list of conditions and the following disclaimer in the documentation
+%%    and/or other materials provided with the distribution.
+%%
+%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+%% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+%% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+%% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+%% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+%% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+%% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+%% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+%% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+%% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+%% POSSIBILITY OF SUCH DAMAGE.
+%%
+%% The views and conclusions contained in the software and documentation are
+%% those of the authors and should not be interpreted as representing official
+%% policies, either expressed or implied, of copyright holder.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{nm} = } vectorNorm (@var{v})
+%% @deftypefnx {Function File} {@var{nm} = } vectorNorm (@var{v},@var{n})
+%% Compute norm of a vector, or of a set of vectors
+%%
+%% Without extra arguments, returns the euclidean norm of vector V.
+%% Optional argument @var{n} specifies the norm to use. N can be any value
+%% greater than 0. 
+%% @table @samp
+%% @item  N=1 
+%%   City lock norm.
+%% @item  N=2 
+%%   Euclidean norm.
+%% @item N=inf 
+%%   Compute max coord.
+%% @end table
+%%
+%%   When @var{v} is a MxN array, compute norm for each vector of the array.
+%%   Vector are given as rows. Result is then a Mx1 array.
+%%
+%%   Example
+%%
+%% @example
+%%   n1 = vectorNorm([3 4])
+%%   n1 =
+%%       5
+%%
+%%   n2 = vectorNorm([1, 10], inf)
+%%   n2 =
+%%       10
+%% @end example
+%%
+%% @seealso{vectors2d, vectorAngle}
+%% @end deftypefn
+
+function n = vectorNorm(v, varargin)
+
+  % size of vector
+  dim = size(v);
+
+  % extract the type of norm to compute
+  d = 2;
+  if ~isempty(varargin)
+      d = varargin{1};
+  end
+
+  if d==2
+      % euclidean norm: sum of squared coordinates, and take square root
+      if dim(1)==1 || dim(2)==1
+          n = sqrt(sum(v.*v));
+      else
+          n = sqrt(sum(v.*v, 2));
+      end
+  elseif d==1 
+      % absolute norm: sum of absolute coordinates
+      if dim(1)==1 || dim(2)==1
+          n = sum(abs(v));
+      else
+          n = sum(abs(v), 2);
+      end
+  elseif d==inf
+      % infinite norm: uses the maximal corodinate
+      if dim(1)==1 || dim(2)==1
+          n = max(v);
+      else
+          n = max(v, [], 2);
+      end
+  else
+      % Other norms, use explicit but slower expression  
+      if dim(1)==1 || dim(2)==1
+          n = power(sum(power(v, d)), 1/d);
+      else
+          n = power(sum(power(v, d), 2), 1/d);
+      end
+  end
+
+endfunction
+
+%!assert (5, vectorNorm ([3 4]))
+%!assert(10, vectorNorm ([1, 10], inf))
+