%% Demo of the KDRANGEQUERY function.%%%%   Guy Shechter%%   guy at jhu dot edu%%   June 2004%% Generate a set of 1000 reference datapoints in R^2ReferencePts = rand(1000,2); %%% Build the k-d Tree once from the reference datapoints.[tmp, tmp, TreeRoot] = kdtree( ReferencePts, []);%%% and find all the points in the k-d tree that are within 0.4%%% units (D-dimensional Euclidean, 2-norm, distance) from the origin[ PtsInNeighborhood, Dist ] = kdrangequery( TreeRoot, [0 0], 0.4 );%%% Free the k-D Tree from memory.kdtree([],[],TreeRoot);figure; clf; hold on; axis equal%% Plot all the points in the k-D treeplot(ReferencePts(:,1), ReferencePts(:,2),'k.');%% Draw a red circle around every point found in the neighborhoodplot(PtsInNeighborhood(:,1), PtsInNeighborhood(:,2), 'ro');%% Show the arc with radius=0.4 centered at the origin.t=0:.01:pi/2;plot(0.4*cos(t), 0.4*sin(t),'g-','LineWidth',2);