function [adjacent] = FindAdjMatrix(X,model)%==========================================================================% FindAdjMatrix: Caculating adjacency matrix%% Input:%  X [dim x num_data] Input data.%  model [struct] obtained from svdd.m %% Output:%  adjacent [num_data x num_data] %     1 for connected, 0 for disconnected (violated), -1 (outliers, BSV)%% Description%	The Adjacency matrix between pairs of points whose images lie in%	or on the sphere in feature space. %	(i.e. points that belongs to one of the clusters in the data space)%%	given a pair of data points that belong to different clusters,%	any path that connects them must exit from the sphere in feature%	space. Such a path contains a line segment of points y, such that:%	kdist2(y,model)>model.r.%	Checking the line segment is implemented by sampling a number of %   points (10 points).%	%	BSVs are unclassfied by this procedure, since their feature space %	images lie outside the enclosing sphere.( adjcent(bsv,others)=-1 )%%==========================================================================% January 13, 2009% Implemented by Daewon Lee% WWW: http://sites.google.com/site/daewonlee/%==========================================================================% samples are column vectorsN=size(X,2);adjacent = zeros(N);R=model.r+10^(-7);  % Squared radius of the minimal enclosing ballfor i = 1:N %rows   for j = 1:N %columns       % if the j is adjacent to i - then all j adjacent's are also adjacent to i.       if j<i         if (adjacent(i,j) == 1)              adjacent(i,:) = (adjacent(i,:) | adjacent(j,:));          end       else            % if adajecancy already found - no point in checking again            if (adjacent(i,j) ~= 1)                % goes over 10 points in the interval between these 2 Sample points                adj_flag = 1; % unless a point on the path exits the shpere - the points are adjacnet                for interval = 0:0.1:1                    z = X(:,i) + interval * (X(:,j) - X(:,i));                    % calculates the sub-point distance from the sphere's center                     d = kdist2(z, model);                    if d > R                       adj_flag = 0;                       break;                    end                end                if adj_flag == 1                   adjacent(i,j) = 1;                   adjacent(j,i) = 1;                end            end        end     endend