1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
## Copyright (C) 2024 David Legland
## All rights reserved.
##
## 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 AUTHOR 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 the copyright holders.
function edges = knnGraph(nodes, varargin)
%KNNGRAPH Create the k-nearest neighbors graph of a set of points.
%
% EDGES = knnGraph(NODES)
%
% Example
% nodes = rand(10, 2);
% edges = knnGraph(nodes);
% drawGraph(nodes, edges);
%
% See also
% graphs
% ------
% Author: David Legland
% E-mail: david.legland@inrae.fr
% Created: 2008-07-28, using Matlab 7.4.0.287 (R2007a)
% Copyright 2008-2023 INRA - BIA PV Nantes - MIAJ Jouy-en-Josas
% get number of neighbors for each node
k = 2;
if ~isempty(varargin)
k = varargin{1};
end
% init size of arrays
n = size(nodes, 1);
edges = zeros(k*n, 2);
% iterate on nodes
for i = 1:n
dists = distancePoints(nodes(i,:), nodes);
[dists, inds] = sort(dists); %#ok<ASGLU>
for j = 1:k
edges(k*(i-1)+j, :) = [i inds(j+1)];
end
end
% remove double edges
edges = unique(sort(edges, 2), 'rows');
|
